Patent Publication Number: US-9419979-B2

Title: Increased communication security

Description:
RELATED APPLICATIONS 
     The present application is a continuation-in-part of U.S. patent application Ser. No. 14/231,625, filed Mar. 31, 2014, entitled “INCREASED COMMUNICATION SECURITY,” naming Vishnu Sharma as the inventor. That application is incorporated herein by reference in its entirety and for all purposes. 
     The present application is related to U. S. patent application Ser. No. 14/470,906, filed Aug. 27, 2014, entitled “INCREASED COMMUNICATION SECURITY,” naming Vishnu Sharma as the inventor. The present application is also related to U.S. patent application Ser. No. 14/470,914, filed Aug. 27, 2014, entitled “INCREASED COMMUNICATION SECURITY,” naming Vishnu Sharma as the inventor. The present application is also related to U.S. patent application Ser. No. 14/470,917, filed Aug. 27, 2014, entitled “INCREASED COMMUNICATION SECURITY,” naming Vishnu Sharma as the inventor. Those applications are incorporated herein by reference in their entirety and for all purposes. 
    
    
     BACKGROUND 
     The Constrained Application Protocol (CoAP) is a protocol for allowing computer systems or devices to communicate by exchanging messages. The protocol specifies certain parameters related to message format and message exchange rules. Messages sent over CoAP can be relatively small in size, and therefore, CoAP allows communication between computer systems or devices with limited processing resources and/or limited storage resources. These computer systems or devices are sometimes referred to as “constrained nodes” or “constrained devices.” 
     To address security concerns associated with communication via CoAP messages, it has been suggested that messages sent over CoAP use Datagram Transport Layer Security (DTLS). Although DTLS can increase the security of communications, it does not provide for authentication of the sender of the CoAP message. 
     SUMMARY 
     Embodiments disclosed herein are directed to increased security for communication of messages between computer systems or devices. 
     In one embodiment, a method of increasing communication security may include receiving a first message associated with communication between a first computer system and a second computer system, wherein the receiving further includes receiving the first message at a third computer system. The method may also include performing, at the third computer system, processing associated with the first message. The method may also include generating, responsive to the processing, a second message including a first data portion and a second data portion, wherein the first data portion is associated with a security token, wherein the first data portion includes a first instance of a session key, and wherein the second data portion includes a second instance of the session key. The method may further include communicating the second message from the third computer system for delivery to the first computer system. 
     In another embodiment, an apparatus may include a communication interface configured to receive a first message associated with communication between a first computer system and a second computer system. The apparatus may also include a security component configured to perform processing associated with the first message. The apparatus may also include a message generation component configured to generate, responsive to the processing, a second message including a first data portion and a second data portion, wherein the first data portion is associated with a security token, wherein the first data portion includes a first instance of a session key, and wherein the second data portion includes a second instance of the session key. The communication interface may be further configured to communicate the second message. 
     In yet another embodiment, an apparatus may include means for receiving a first message associated with communication between a first computer system and a second computer system, wherein the means for receiving further includes means for receiving the first message at a third computer system. The apparatus may also include means for performing, at the third computer system, processing associated with the first message. The apparatus may also include means for generating, responsive to the processing, a second message including a first data portion and a second data portion, wherein the first data portion is associated with a security token, wherein the first data portion includes a first instance of a session key, and wherein the second data portion includes a second instance of the session key. The apparatus may further include means for communicating the second message from the third computer system for delivery to the first computer system. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to the same or similar elements. 
         FIG. 1  shows a system for increasing communication security in accordance with one embodiment. 
         FIG. 2  shows a CoAP message in accordance with one embodiment. 
         FIG. 3  shows a portion associated with a header of a CoAP message in accordance with one embodiment. 
         FIG. 4  shows a portion associated with at least one option of a CoAP message in accordance with one embodiment. 
         FIG. 5A  shows a CoAP message associated with a request in accordance with one embodiment. 
         FIG. 5B  shows a CoAP message associated with a response in accordance with one embodiment. 
         FIG. 6A  shows a first portion of a flowchart of a process for increasing communication security in accordance with one embodiment. 
         FIG. 6B  shows a second portion of a flowchart of a process for increasing communication security in accordance with one embodiment. 
         FIG. 7  shows data associated with at least one key in accordance with one embodiment. 
         FIG. 8  shows a flowchart of a process for generating a CoAP message in accordance with one embodiment. 
         FIG. 9  shows a flowchart of a process for processing a CoAP message in accordance with one embodiment. 
         FIG. 10  shows a flowchart of a process for performing message validation in accordance with one embodiment. 
         FIG. 11  shows a flowchart of a process for determining whether at least one condition for message invalidity is met in accordance with one embodiment. 
         FIG. 12  shows a computer system upon which one or more embodiments may be implemented. 
         FIG. 13A  shows a first portion of a flowchart of a process for increasing communication security in accordance with one embodiment. 
         FIG. 13B  shows a second portion of a flowchart of a process for increasing communication security in accordance with one embodiment. 
         FIG. 14  shows a system for increasing communication security in accordance with one embodiment. 
         FIG. 15  shows a flowchart of a process for configuring permissions in accordance with one embodiment. 
         FIG. 16  shows permissions configuration data in accordance with one embodiment. 
         FIG. 17A  shows a CoAP message in accordance with one embodiment. 
         FIG. 17B  shows a CoAP message in accordance with one embodiment. 
         FIG. 18  shows a flowchart of a process for generating a message associated with communication between a plurality of computer systems in accordance with one embodiment. 
         FIG. 19  shows a data portion associated with a security token in accordance with one embodiment. 
         FIG. 20A  shows a first portion of a flowchart of a process for performing processing associated with a message in accordance with one embodiment. 
         FIG. 20B  shows a second portion of a flowchart of a process for performing processing associated with a message in accordance with one embodiment. 
         FIG. 21  shows data associated with at least one session key in accordance with one embodiment. 
         FIG. 22  shows a flowchart of a process for performing processing associated with a message in accordance with one embodiment. 
         FIG. 23  shows data associated with at least one session key accessible to a caller system in accordance with one embodiment. 
         FIG. 24A  shows a CoAP message in accordance with one embodiment. 
         FIG. 24B  shows a CoAP message in accordance with one embodiment. 
         FIG. 25  shows a flowchart of a process for generating a message including a data portion associated with a security token in accordance with one embodiment. 
         FIG. 26A  shows a first portion of a flowchart of a process for performing processing associated with a message in accordance with one embodiment. 
         FIG. 26B  shows a second portion of a flowchart of a process for performing processing associated with a message in accordance with one embodiment. 
         FIG. 27  shows data associated with at least one session key accessible to a target system in accordance with one embodiment. 
         FIG. 28  shows a flowchart of a process for performing message validation in accordance with one embodiment. 
         FIG. 29  shows a flowchart of a process for generating a message associated with successful access of a session key in accordance with one embodiment. 
         FIG. 30A  shows a first portion of a flowchart of a process for increasing communication security in accordance with one embodiment. 
         FIG. 30B  shows a second portion of a flowchart of a process for increasing communication security in accordance with one embodiment. 
         FIG. 30C  shows a third portion of a flowchart of a process for increasing communication security in accordance with one embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. While the present invention will be discussed in conjunction with the following embodiments, it will be understood that they are not intended to limit the present invention to these embodiments alone. On the contrary, the present invention is intended to cover alternatives, modifications, and equivalents which may be included with the spirit and scope of the present invention as defined by the appended claims. Furthermore, in the following detailed description of the present invention, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, embodiments of the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects of the present invention. 
     Notation and Nomenclature 
     Some regions of the detailed descriptions which follow are presented in terms of procedures, logic blocks, processing and other symbolic representations of operations on data bits within a computer memory. These descriptions and representations are the means used by those skilled in the art to most effectively convey the substance of their work to others skilled in the art. In the present application, a procedure, logic block, process, or the like, is conceived to be a self-consistent sequence of steps or instructions leading to a desired result. The steps are those requiring physical manipulations of physical quantities. Usually, although not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated in a computer system. 
     It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise as apparent from the following discussions, it is appreciated that throughout the present invention, discussions utilizing the terms such as “aborting,” “accepting,” “accessing,” “activating,” “adding,” “adjusting,” “allocating,” “allowing,” “analyzing,” “applying,” “assembling,” “assigning,” “authenticating,” “authorizing,” “balancing,” “blocking,” “calculating,” “capturing,” “causing,” “changing,” “charging,” “combining,” “comparing,” “collecting,” “communicating,” “comparing,” “configuring,” “controlling,” “converting,” “correlating,” “creating,” “deactivating,” “debugging,” “decreasing,” “decrypting,” “defining,” “delivering,” “depicting,” “detecting,” “determining,” “discharging,” “displaying,” “downloading,” “enabling,” “encrypting,” “establishing,” “executing,” “forwarding,” “flipping,” “generating,” “grouping,” “hiding,” “identifying,” “ignoring,” “increasing,” “initiating,” “instantiating,” “interacting,” “measuring,” “modifying,” “monitoring,” “moving,” “outputting,” “parsing,” “performing,” “placing,” “presenting,” “processing,” “programming,” “providing,” “provisioning,” “querying,” “receiving,” “reformatting,” “regulating,” “removing,” “rendering,” “repeating,” “resuming,” “retaining,” “sampling,” “simulating,” “selecting,” “sending,” “sorting,” “storing,” “subtracting,” “suspending,” “tracking,” “transcoding,” “transforming,” “transmitting,” “unblocking,” “using,” “validating,” “verifying,” or the like, may refer to the action and/or processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system&#39;s registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission and/or display devices. 
     Embodiments 
       FIG. 1  shows system  100  for increasing communication security in accordance with one embodiment. As shown in  FIG. 1 , computer system  110  and computer system  120  may communicate Constrained Application Protocol (CoAP) messages over connection  130 . 
     Authentication data may be generated and included in one or more of the CoAP messages. The authentication data may allow message validation to be performed for verifying the authenticity of the sender of the CoAP message and/or the integrity of the CoAP message. And in one embodiment, where a CoAP message includes a nonce, security can be improved by allowing the recipient of the CoAP message to detect and/or act on a replay attack. 
       FIG. 2  shows CoAP message  200  in accordance with one embodiment. CoAP message  200  may be part of a bit stream or byte stream used for communication between a plurality of systems or devices (e.g., computer system  110 , computer system  120 , etc.). The term “CoAP message” as used herein may refer to data which is formatted and/or communicated in accordance with CoAP. 
     As shown in  FIG. 2 , CoAP message  200  may include portion  210  associated with a header, portion  220  associated with a token, portion  230  associated with at least one option, portion  240  associated with a payload marker, and portion  250  associated with a payload, or some combination thereof. Authentication data  260  may be included in portion  250  in one embodiment. 
     Portion  210  may include one or more sub-portions of data. For example, as shown in  FIG. 3 , portion  210  may include portion  310  associated with a version, portion  320  associated with a message type, portion  330  associated with a token length, portion  340  associated with a code, portion  350  associated with a message identifier, some combination thereof, etc. 
     Portion  310  may be data associated with a CoAP version number. In one embodiment, portion  310  may be two bits in length. And in other embodiments, portion  310  may be larger or smaller than two bits in length. 
     As shown in  FIG. 3 , portion  320  may be data associated with a message type of CoAP message  200 . For example, the message type associated with portion  320  may be confirmable, non-confirmable, acknowledgement, reset, etc. 
     In one embodiment, portion  320  may be two bits in length. And in other embodiments, portion  320  may be larger or smaller than two bits in length. 
     Portion  330  may be data associated with a length of a token (e.g., the length of portion  220  of  FIG. 2 ) of CoAP message  200 . In one embodiment, portion  330  may be four bits in length. And in other embodiments, portion  330  may be larger or smaller than four bits in length. 
     As shown in  FIG. 3 , portion  340  may be data associated with a code. In one embodiment, the code associated with portion  340  may be a method code. For example, the code associated with portion  340  may be “GET,” “POST,” “PUT,” “DELETE,” etc. In one embodiment, the code associated with portion  340  may be a response code. For example, the code associated with portion  340  may be “Created,” “Deleted,” “Valid,” “Changed,” “Content,” “Bad Request,” “Unauthorized,” “Bad Option,” “Forbidden,” “Not Found,” etc. 
     In one embodiment, portion  340  may be eight bits in length. And in other embodiments, portion  340  may be larger or smaller than eight bits in length. 
     Portion  350  may be data associated with a message identifier. The message identifier associated with portion  350  may be used to match or group CoAP messages based on message type (e.g., to match or group a confirmable or non-confirmable CoAP message with an acknowledgement or reset CoAP message) in one embodiment. For example, a confirmable or non-confirmable CoAP message may be matched or grouped with an acknowledgement or reset CoAP message. 
     In one embodiment, the message identifier associated with portion  350  may be used (e.g., in conjunction with a nonce) to distinguish a properly re-sent message (e.g., with a different nonce than a previous message with the same message identifier) from a replay attack (e.g., resulting from the sending of a message with the same nonce and the same message identifier). 
     In one embodiment, portion  350  may be 16 bits in length. And in other embodiments, portion  350  may be larger or smaller than 16 bits in length. 
     Although  FIG. 3  shows portion  210  with a specific number and type of portions, it should be appreciated that portion  210  may include a different number and/or type of portions in other embodiments. For example, portion  210  may include fewer portions or at least one additional portion. As another example, a plurality of portions of portion  210  may be combined into a smaller number of portions. Although  FIG. 3  shows portion  210  with a specific organization of portions, it should be appreciated that portion  210  may include a different organization of portions in other embodiments. 
     Turning back to  FIG. 2 , portion  220  may be associated with a token. The token associated with portion  220  may be used to match or group at least one request (e.g., one or more CoAP messages) to at least one response (e.g., one or more other CoAP messages) in one embodiment. 
     In one embodiment, portion  220  may be at most eight bits in length. The length of portion  220  may be associated with and/or dictated by portion  330  in one embodiment. And in other embodiments, portion  220  may be larger than eight bits in length. 
     As shown in  FIG. 2 , portion  230  may be associated with at least one option. The at least one option associated with portion  230  may include a unique identifier in one embodiment. For example, the at least one option associated with portion  230  may include a unique identifier associated with a sender of a CoAP message (e.g., computer system  110 , computer system  120 , etc.). In one embodiment, the unique identifier may be included in portion  230  as an option associated with a query (e.g., a “Uri-Query” option). 
     In one embodiment, the at least one option associated with portion  230  may include an authentication mechanism identifier. The term “authentication mechanism identifier” as used herein may be any data or metadata that identifies or is otherwise associated with an authentication mechanism. 
     For example, the at least one option associated with portion  230  may include an authentication mechanism identifier associated with an authentication mechanism used to generate authentication data  260 . In one embodiment, the authentication mechanism identifier may be included in portion  230  as an option associated with a query (e.g., a “Uri-Query” option). 
     The at least one option associated with portion  230  may include a nonce in one embodiment. The nonce may be a random number, a pseudorandom number, a sequential or incremental number (e.g., a number with a predetermined offset from the nonce of a previously-transmitted CoAP message), a timestamp, etc. In one embodiment, the nonce may be included in portion  230  as an option associated with a query (e.g., a “Uri-Query” option). 
     In one embodiment, the at least one option associated with portion  230  may include a max-age value. For example, the max-age value may be used to indicate that the message is not to be cached by an intermediary system or device (e.g., situated between the sender of the CoAP message and the ultimate recipient of the CoAP message) such as a proxy server or other type of computer system or device. 
     The at least one option associated with portion  230  may include other data in one embodiment. For example, the at least one option associated with portion  230  may include data associated with a host, data associated with a port, data associated with a path, some combination thereof, etc. As another example, the at least one option associated with portion  230  may include data associated with a query (e.g., including at least one parameter). In one embodiment, each parameter of the query may be encoded in portion  230  as a respective option. 
     In one embodiment, portion  230  may include one or more respective sub-portions of data associated with each option of the at least one option. For example, as shown in  FIG. 4 , for each option of the at least one option (e.g.,  410 ,  420 ,  430 , etc.), portion  230  may include a respective portion associated with an option identifier (e.g.,  412 ,  422 ,  432 , etc.), a respective portion associated with an option length (e.g.,  414 ,  424 ,  434 , etc.), a respective portion associated with an option value (e.g.,  416 ,  426 ,  436 , etc.), etc. 
     A portion associated with an option identifier (e.g.,  412 ,  422 ,  432 , etc.) may include data associated with an option number corresponding to an option associated with the portion (e.g., option  410 , option  420 , option  430 , etc.). For example, where option  410  is associated with a port (e.g., a “Uri-Port” option), portion  412  may include data associated with a numerical value of “7” (e.g., where “7” is the option number corresponding to an option associated with a port) as the option identifier. As another example, where option  420  is associated with a path (e.g., a “Uri-Path” option), portion  422  may include data associated with a numerical value of “11” (e.g., where “11” is the option number corresponding to an option associated with a path) as the option identifier. And as yet another example, where option  430  is associated with a query (e.g., a “Uri-Query” option), portion  432  may include data associated with a numerical value of “15” (e.g., where “15” is the option number corresponding to an option associated with a query) as the option identifier. 
     In one embodiment, a portion associated with an option identifier (e.g.,  412 ,  422 ,  432 , etc.) may include data associated with an option delta corresponding to an option associated with the portion (e.g., option  410 , option  420 , option  430 , etc.). An option delta may be the difference between the current option number and the option number of the preceding option in one embodiment. For the first option, a numerical value of “0” may be used for the option number of the preceding option. A delta of “0” may be used for subsequent instances of the same option. 
     For example, where portion  412  is associated with an option number corresponding to “7” and option  410  is the first option, then portion  412  may include data associated with a numerical value of “7” (e.g., the delta or difference between “0” and “7”) as the option identifier. As another example, where portion  412  is associated with an option number corresponding to “7” and portion  422  is associated with an option number corresponding to “11,” then portion  422  may include data associated with a numerical value of “4” (e.g., the delta or difference between “7” and “11”) as the option identifier. As yet another example, where portion  422  is associated with an option number corresponding to “11” and portion  432  is associated with an option number corresponding to “15,” then portion  432  may include data associated with a numerical value of “4” (e.g., the delta or difference between “11” and “15”) as the option identifier. 
     A portion associated with an option length (e.g.,  414 ,  424 ,  434 , etc.) may include a length of a corresponding portion associated with an option value (e.g.,  416 ,  426 ,  436 , etc.). For example, where portion  416  includes data associated with a port of “5683,” portion  414  may include data associated with a length of two bytes (e.g., where two bytes are used to encode a numerical value of “5683”). As another example, where portion  426  includes data associated with a path of “temperature,” portion  424  may include data associated with a length of 11 bytes (e.g., where 11 bytes are used to encode the path of “temperature”). As yet another example, where portion  436  includes data associated with a unique identifier of “uid=cs110,” portion  434  may include data associated with a length of 9 bytes (e.g., where 9 bytes are used to encode the unique identifier of “uid=cs110”). 
     Although  FIG. 4  shows at least one option  230  with a specific number and type of portions, it should be appreciated that at least one option  230  may include a different number and/or type of portions in other embodiments. For example, at least one option  230  may include fewer portions (e.g., a smaller number of options, a smaller number of respective sub-portions associated with each option, etc.) or at least one additional portion (e.g., a larger number of options, a larger number of respective sub-portions associated with each option, etc.). As another example, a plurality of portions of at least one option  230  may be combined into a smaller number of portions. Although  FIG. 4  shows at least one option  230  with a specific organization of portions, it should be appreciated that at least one option  230  may include a different organization of portions in other embodiments. 
     Turning back to  FIG. 2 , portion  240  may be associated with a payload marker. Portion  240  may be included in CoAP message  200  if portion  250  (e.g., associated with a payload) is included in CoAP message  200 . 
     Portion  250  may be associated with a payload. In one embodiment, portion  250  may include only authentication data  260 . In this case, the payload associated with portion  250  may include only authentication data  260  and no other data, content, etc. Alternatively, portion  250  may include data and/or content in addition to authentication data  260 . In this case, authentication data  260  may be included in the last portion of portion  250  (e.g., with other data and/or content of the payload preceding authentication data  260 ), the first portion of portion  250  (e.g., with other data and/or content of the payload following authentication data  260 ), an intermediary portion of portion  250  (e.g., with other data and/or content of the payload both preceding and following authentication data  260 ), etc. 
     In one embodiment, CoAP message  200  may be associated with a request sent from at least one computer system to at least one other computer system. In this case, CoAP message  200  may include data associated with a request for the at least one recipient to perform at least one operation. 
     Alternatively, CoAP message  200  may be associated with a response sent from at least one computer system to at least one other computer system. In this case, CoAP message  200  may include data and/or content associated with a corresponding request (e.g., of a previously-communicated CoAP message). For example, CoAP message  200  may include data and/or content accessed as a result of performing at least one operation requested via a previously-communicated CoAP message. 
     A first CoAP message (e.g., associated with a request) and a second CoAP message (e.g., associated with a response to the request of the first CoAP message) may share a common message identifier (e.g., associated with data of portion  350  of  FIG. 3 ) in one embodiment. A first CoAP message (e.g., associated with a request) and a second CoAP message (e.g., associated with a response to the request of the first CoAP message) may share a common token (e.g., associated with data of portion  220  of  FIG. 2 ) in one embodiment. 
     In one embodiment, where a first CoAP message is associated with a request and a second CoAP message is associated with a response to the request (e.g., of the first CoAP message), a message type (e.g., associated with data of portion  320  as shown in  FIG. 3 ) associated with the second CoAP message may correspond to and/or be determined by a message type (e.g., associated with data of portion  320  as shown in  FIG. 3 ) associated with the first CoAP message. For example, where the first CoAP message is associated with a message type of “confirmable,” the second CoAP message may be associated with a message type of “confirmable” or “acknowledgement.” 
     In one embodiment, where a first CoAP message is associated with a request and a second CoAP message is associated with a response to the request (e.g., of the first CoAP message), a response code (e.g., associated with data of portion  340  as shown in  FIG. 3 ) associated with the second CoAP message may correspond to and/or be determined by a method code (e.g., associated with data of portion  340  as shown in  FIG. 3 ) associated with the first CoAP message. For example, where the first CoAP message is associated with a method code of “GET,” the second CoAP message may be associated with a response code of “Content” (e.g., including the data and/or content requested using the first CoAP message). 
       FIG. 5A  shows CoAP message  500 A associated with a request in accordance with one embodiment. As shown in  FIG. 5A , CoAP message  500 A may include data associated with a header, where the data associated with the header includes data associated with a version (e.g., “1”), a message type (e.g., “CON” or confirmable), a token length (e.g., “1” associated with a length of 1 byte), a code (e.g., a method code of “GET”), and a message identifier (e.g., “0xbc90”). Data associated with a token (e.g., “0x71”) may also be included in CoAP message  500 A. 
     CoAP message  500 A may include data associated with at least one option. For example, CoAP message  500 A may include data associated with a host (e.g., an option value of “www.example.com”), data associated with a port (e.g., an option value of “5683”), data associated with a path (e.g., an option value of “sensors,” an option value of “temperature,” etc.), some combination thereof, etc. In this case, at least one option associated with CoAP message  500 A may correspond to a URI of “coap://www.example.com:5683/sensors/temperature”, “coap://www.example.com/sensors/temperature”, “coaps://www.example.com:5683/sensors/temperature”, “coaps://www.example.com/sensors/temperature”, some combination thereof, etc. 
     As another example, CoAP message  500 A may include data associated with a max-age value (e.g., an option value of “0”). In this case, a max-age value of “0” may be used to indicate that CoAP message  500 A is not to be cached by an intermediary system or device (e.g., situated between the sender of the CoAP message  500 A and the ultimate recipient of the CoAP message  500 A) such as a proxy server or other type of computer system or device. 
     As a further example, CoAP message  500 A may include data associated with a query (e.g., including one or more parameters). An option value of “uid=cs110” (e.g., associated with a first parameter) may be associated with a unique identifier (e.g., “cs110”) of a sender of CoAP message  500 A (e.g., computer system  110 ). An option value of “hs256=1” (e.g., associated with a second parameter) may be associated with an authentication mechanism (e.g., hash-based message authentication code (HMAC) utilizing a hash function of SHA256) used to generate the authentication data (e.g., “Authentication Data 1”) included in CoAP message  500 A. An option value of “nonce=1” (e.g., associated with a third parameter) may be associated with a nonce (e.g., with a value of “1”) included in CoAP message  500 A. 
     In one embodiment, one or more portions of CoAP message  500 A may be associated with a URI including at least one parameter of a query. For example, CoAP message  500 A may be associated with a URI of “coap://www.example.com:5683/sensors/temperature?uid=cs110&amp;hs256=1&amp;nonce=1” or “coaps://www.example.com:5683/sensors/temperature?uid=cs110&amp;hs256=1&amp;nonce=1”. 
     CoAP message  500 A may include data associated with at least one option length. For example, CoAP message  500 A may include data associated with a first option length (e.g., 15 bytes) corresponding to data associated with a first option value (e.g., “www.example.com”), a second option length (e.g., 2 bytes) corresponding to data associated with a second option value (e.g., “5683”), a third option length (e.g., 7 bytes) corresponding to data associated with a third option value (e.g., “sensors”), etc. 
     As shown in  FIG. 5A , CoAP message  500 A may include data associated with at least one option identifier. The at least one option identifier may include data associated with an option number and/or an option delta in one embodiment. For example, CoAP message  500 A may include data associated with a first numerical value (e.g., “3”) as a first option identifier corresponding to a first option (e.g., associated with a host), where the first numerical value (e.g., “3”) may be the delta or difference between the current option number (e.g., “3”) and the option number of the preceding option (e.g., “0” in this case since this is the first option). As such, the first numerical value of “3” may correspond to an option number of “3.” 
     As another example, CoAP message  500 A may include data associated with a second numerical value (e.g., “4”) as a second option identifier corresponding to a second option (e.g., associated with a port), where the second numerical value (e.g., “4”) may be the delta or difference between the current option number (e.g., “7”) and the option number of the preceding option (e.g., “3”). As such, the second numerical value of “4” may correspond to an option number of “7.” 
     As a further example, CoAP message  500 A may include data associated with a third numerical value (e.g., “4”) as a third option identifier corresponding to a third option (e.g., associated with a path), where the third numerical value (e.g., “4”) may be the delta or difference between the current option number (e.g., “11”) and the option number of the preceding option (e.g., “7”). As such, the third numerical value of “4” may correspond to an option number of “11.” 
     As shown in  FIG. 5A , CoAP message  500 A may include data associated with a payload marker (e.g., “0xFF”). CoAP message  500 A may include data associated with a payload, where the data associated with a payload may include authentication data (e.g., “Authentication Data 1”). 
     Although  FIG. 5A  shows CoAP message  500 A with a specific number and type of portions, it should be appreciated that CoAP message  500 A may include a different number and/or type of portions in other embodiments. For example, CoAP message  500 A may include fewer portions or at least one additional portion. As another example, a plurality of portions of CoAP message  500 A may be combined into a smaller number of portions. Although  FIG. 5A  shows CoAP message  500 A with a specific organization of portions, it should be appreciated that CoAP message  500 A may include a different organization of portions in other embodiments. 
     In one embodiment, data associated with at least one option may be excluded from CoAP message  500 A. For example, data (e.g., associated with a host, a port, a path, a max-age value, or some combination thereof) used by intermediary systems or devices (e.g., situated between the sender of CoAP message  500 A and the ultimate recipient of CoAP message  500 A) such as a proxy server or other type of computer system or device may be excluded in one or more embodiments where intermediary systems or devices do not exist or are unlikely to exist. 
       FIG. 5B  shows CoAP message  500 B associated with a response in accordance with one embodiment. As shown in  FIG. 5B , CoAP message  500 B may include data associated with a header, where the data associated with the header includes data associated with a version (e.g., “1”), a message type (e.g., “ACK” or acknowledgement), a token length (e.g., “1” associated with a length of 1 byte), a code (e.g., a response code of “Content”), and a message identifier (e.g., “0xbc90”). Data associated with a token (e.g., “0x71”) may also be included in CoAP message  500 B. 
     CoAP message  500 B may include data associated with at least one option. For example, CoAP message  500 B may include data associated with a max-age value (e.g., an option value of “0”). In this case, a max-age value of “0” may be used to indicate that CoAP message  500 B is not to be cached by an intermediary system or device (e.g., situated between the sender of the CoAP message  500 B and the ultimate recipient of the CoAP message  500 B) such as a proxy server or other type of computer system or device. 
     As another example, CoAP message  500 B may include data associated with a query (e.g., including one or more parameters). An option value of “uid=cs120” (e.g., associated with a first parameter) may be associated with a unique identifier (e.g., “cs120”) of a sender of CoAP message  500 B (e.g., computer system  120 ). An option value of “hs256=1” (e.g., associated with a second parameter) may be associated with an authentication mechanism (e.g., hash-based message authentication code (HMAC) utilizing a hash function of SHA256) used to generate the authentication data (e.g., “Authentication Data 2”) included in CoAP message  500 B. An option value of “nonce=1” (e.g., associated with a third parameter) may be associated with a nonce (e.g., with a value of “1”) included in CoAP message  500 B. 
     CoAP message  500 B may include data associated with at least one option length. For example, CoAP message  500 B may include data associated with a first option length (e.g., 1 byte) corresponding to data associated with a first option value (e.g., “0”), a second option length (e.g., 9 bytes) corresponding to data associated with a second option value (e.g., “uid=cs120”), a third option length (e.g., 7 bytes) corresponding to data associated with a third option value (e.g., “hs256=1”), etc. 
     As shown in  FIG. 5B , CoAP message  500 B may include data associated with at least one option identifier. The at least one option identifier may include data associated with an option number and/or an option delta in one embodiment. For example, CoAP message  500 B may include data associated with a first numerical value (e.g., “14”) as a first option identifier corresponding to a first option (e.g., associated with a max-age value), where the first numerical value (e.g., “14”) may be the delta or difference between the current option number (e.g., “14”) and the option number of the preceding option (e.g., “0” in this case since this is the first option). As such, the first numerical value of “14” may correspond to an option number of “14.” 
     As another example, CoAP message  500 B may include data associated with a second numerical value (e.g., “1”) as a second option identifier corresponding to a second option (e.g., associated with a query), where the second numerical value (e.g., “1”) may be the delta or difference between the current option number (e.g., “15”) and the option number of the preceding option (e.g., “14”). As such, the second numerical value of “1” may correspond to an option number of “15.” 
     As a further example, CoAP message  500 B may include data associated with a third numerical value (e.g., “0”) as a third option identifier corresponding to a third option (e.g., associated with a query), where the third numerical value (e.g., “0”) may be the delta or difference between the current option number (e.g., “15”) and the option number of the preceding option (e.g., “15”). As such, the third numerical value of “0” may correspond to an option number of “15.” 
     As shown in  FIG. 5B , CoAP message  500 B may include data associated with a payload marker (e.g., “0xFF”). CoAP message  500 B may include data associated with a payload, where the data associated with a payload may include authentication data (e.g., “Authentication Data 2”) and/or other data or content (e.g., “22.5 C”). 
     In one embodiment, CoAP message  500 A (e.g., associated with a request) and CoAP message  500 B (e.g., associated with a response to the request) may share a common message identifier (e.g., “0xbc90”). CoAP message  500 A (e.g., associated with a request) and CoAP message  500 B (e.g., associated with a response to the request) may share a common token (e.g., “0x71”) in one embodiment. 
     In one embodiment, a message type associated with CoAP message  500 B (e.g., “ACK” or acknowledgement) may correspond to and/or be determined by a message type associated with CoAP message  500 A (e.g., “CON” or confirmable). And in one embodiment, a response code associated with CoAP message  500 B (e.g., “Content”) may correspond to and/or be determined by a method code associated with CoAP message  500 A (e.g., “GET”). In this case, CoAP message  500 B may include the data or content requested using CoAP message  500 A (e.g., the temperature of “22.5 C”). 
     Although  FIG. 5B  shows CoAP message  500 B with a specific number and type of portions, it should be appreciated that CoAP message  500 B may include a different number and/or type of portions in other embodiments. For example, CoAP message  500 B may include fewer portions or at least one additional portion. As another example, a plurality of portions of CoAP message  500 B may be combined into a smaller number of portions. Although  FIG. 5B  shows CoAP message  500 B with a specific organization of portions, it should be appreciated that CoAP message  500 B may include a different organization of portions in other embodiments. 
     In one embodiment, data associated with at least one option may be excluded from CoAP message  500 B. For example, data (e.g., associated with a host, a port, a path, a max-age value, or some combination thereof) used by intermediary systems or devices (e.g., situated between the sender of CoAP message  500 B and the ultimate recipient of CoAP message  500 B) such as a proxy server or other type of computer system or device may be excluded in one or more embodiments where intermediary systems or devices do not exist or are unlikely to exist. 
     Although  FIG. 2  shows CoAP message  200  with a specific number and type of portions, it should be appreciated that CoAP message  200  may include a different number and/or type of portions in other embodiments. For example, CoAP message  200  may include fewer portions or at least one additional portion. As another example, a plurality of portions of CoAP message  200  may be combined into a smaller number of portions. Although  FIG. 2  shows CoAP message  200  with a specific organization of portions, it should be appreciated that CoAP message  200  may include a different organization of portions in other embodiments. For example, authentication data  260  may be included in at least one portion of CoAP message  200  other than portion  250 . 
     Turning back to  FIG. 1 , computer system  110  and computer system  120  may each include a respective security component (e.g.,  112  and  122 ) configured to generate authentication data (e.g., to be included in one or more CoAP messages to be communicated) and/or perform message validation (e.g., with respect to at least one received CoAP message and/or with respect to authentication data included in at least one received CoAP message). A message generation component (e.g., message generation component  114  of computer system  110 , message generation component  124  of computer system  120 , etc.) may generate CoAP messages (e.g., including authentication data generated by security component  112 , security component  122 , etc.) to be communicated. 
     In one embodiment, a CoAP message (e.g.,  200 ,  500 A,  500 B, etc.) may be generated (e.g., using message generation component  114 , message generation component  124 , etc.) based on a uniform resource identifier (URI). As an example, the URI may be formatted as follows: 
     coap://[host or IP address]:[port number]/[path]?[query] 
     One or more portions of the URI (e.g., the host or IP address, the port number, the path, etc.) may each be included in the CoAP message as a respective option (e.g., associated with data of portion  230  as shown in  FIG. 2 ). For example, the host or IP address may be included as a Uri-Host option, the port number as a Uri-Port option, the path as at least one Uri-Path option, etc. The query of the URI may include at least one parameter, where each parameter of the query may be included in the CoAP message (e.g.,  200 ,  500 A,  500 B, etc.) as a respective option (e.g., associated with data of portion  230  as shown in  FIG. 2 ). For example, each parameter may be included in the CoAP message as a respective Uri-Query option. 
     The CoAP message (e.g.,  200 ,  500 A,  500 B, etc.) including authentication data (e.g.,  260 , “Authentication Data 1,” “Authentication Data 2,” etc.) may be communicated using Datagram Transport Layer Security (DTLS) in one embodiment. In this case, the CoAP message (e.g.,  200 ,  500 A,  500 B, etc.) may be generated (e.g., using message generation component  114 , message generation component  124 , etc.) based on a URI that begins with “coaps://.” 
     Computer system  110  and computer system  120  may each include a respective operation component (e.g.,  116  and  126 ) in one embodiment. An operation component (e.g.,  116 ,  126 , etc.) may be configured to perform at least one operation if a received CoAP message is determined to be valid (e.g., based on message validation performed using security component  112 , security component  122 , etc.). 
     In one embodiment, the at least one operation may include at least one operation associated with a method code (e.g., associated with data of portion  340  as shown in  FIG. 3 ) in the CoAP message (e.g.,  200 ,  500 A,  500 B, etc.) and/or at least one operation associated with an option (e.g., associated with data of portion  230  as shown in  FIG. 2 ) of the CoAP message (e.g.,  200 ,  500 A,  500 B, etc.). For example, where a CoAP message (e.g.,  500 A) is associated with a request to get a temperature (e.g., with a method code of “GET” and a Uri-Path option of “temperature” as depicted in  FIG. 5A ), the at least one operation (e.g., performed by operation component  116  of computer system  110 , operation component  126  of computer system  120 , etc.) may include accessing a temperature (e.g., reading a temperature, accessing a stored temperature, etc.). In this case, the operation component (e.g.,  116 ,  126 , etc.) may include a temperature sensor. 
     The at least one operation may include communication of a second CoAP message (e.g.,  500 B) in one embodiment. For example, responsive to determining that a first CoAP message (e.g.,  200 ,  500 A, etc.) is valid, the second CoAP message may be communicated from the recipient of the first CoAP message to the sender of the first CoAP message. 
     In one embodiment, the at least one operation may include an operation associated with a request code (e.g., associated with data of portion  340  as shown in  FIG. 3 ) of the CoAP message (e.g.,  200 ,  500 A,  500 B, etc.). For example, where a CoAP message (e.g.,  500 B) is associated with a response including data and/or content (e.g., with a response code of “Content” and a payload including data associated with a temperature as depicted in  FIG. 5B ), the at least one operation (e.g., performed by operation component  116  of computer system  110 , operation component  126  of computer system  120 , etc.) may include processing of the data (e.g., to generate business intelligence, for charting, for analytics, etc.), performing one or more other operations, etc. 
     If a received CoAP message is determined to be invalid (e.g., based on message validation performed using security component  112 , security component  122 , etc.), an operation component (e.g.,  116  and  126 ) of computer systems  110  and  120  may be configured to perform at least one other operation. For example, the at least one other operation may include ignoring the received CoAP message (e.g., not sending a reply to the received CoAP message, performing no further processing related to the received CoAP message, etc.). As another example, the at least one other operation may include limiting access to the recipient (e.g., to computer system  110  where the CoAP message is received at computer system  110 , to computer system  120  where the CoAP message is received at computer system  120 , etc.) of the sender (e.g., computer system  110 , computer system  120 , at least one other computer system or device, etc.). 
     As shown in  FIG. 1 , connection  130  may be implemented using communication interface  118  (of computer system  110 ) and communication interface  128  (of computer system  120 ). Communication interface  118  and communication interface  128  may each include respective hardware and/or respective software allowing connection  130  to be established and allowing communication of at least one CoAP message over connection  130 . Communication interface  118  and communication interface  128  may allow unidirectional communication and/or bidirectional communication over connection  130  in one embodiment. And in one embodiment, communication interface  118  and communication interface  128  may allow contemporaneous (or simultaneous) bidirectional communication (e.g. “full-duplex” communication) over connection  130 . 
     Connection  130  between computer system  110  and computer system  120  may be a wired connection in one embodiment. For example, connection  130  may be a IEEE 1394 or FireWire® connection, PCI Express® connection, Ethernet connection, SATA connection, eSATA connection, RS-232 connection, I 2 C connection, etc. In one embodiment, connection  130  may be a wireless connection such as a Bluetooth® connection, Near Field Communication (NFC) connection, infrared (IR) connection, IEEE 802.XX connection, cellular connection, etc. 
     In one embodiment, computer system  110  and/or computer system  120  may have limited processing resources and/or limited storage resources. As an example, computer system  110  and/or computer system  120  may be “constrained nodes” or “constrained devices.” In one embodiment, a “constrained device” may be a computer system or device with no larger than an 8-bit microcontroller. And in one or more other embodiments, a “constrained device” may be a computer system or device with at least one microcontroller larger or smaller than 8-bits in size. 
     As another example, computer system  110  and/or computer system  120  may communicate over a “constrained network” such as a 6LowPAN network. In this case, connection  130  may be used to implement and/or be part of a “constrained network.” 
     Computer system  110  may be a client and computer system  120  may be a server in one embodiment. In this case, computer system  110  may communicate requests (e.g., CoAP message  200 , CoAP message  500 A, etc.) to computer system  120 , and computer system  120  may communicate responses (e.g., CoAP message  200 , CoAP message  500 B, etc.) to computer system  110 . 
     Alternatively, computer system  110  may be a server and computer system  120  may be a client in one embodiment. In this case, computer system  120  may communicate requests (e.g., CoAP message  200 , CoAP message  500 A, etc.) to computer system  110 , and computer system  110  may communicate responses (e.g., CoAP message  200 , CoAP message  500 B, etc.) to computer system  120 . 
     Although  FIG. 1  shows system  100  with a specific number and type of systems or devices, it should be appreciated that system  100  may include a different number and/or type of systems or devices in other embodiments. For example, system  100  may include more than one instance of computer system  110  and/or computer system  120  in one or more other embodiments. Where system  100  includes more than one instance of computer system  110 , each instance of computer system  110  may communicate with computer system  120  over a respective connection (e.g., similar to connection  130 ). Where system  100  includes more than one instance of computer system  120 , each instance of computer system  120  may communicate with computer system  110  over a respective connection (e.g., similar to connection  130 ). As such, embodiments can increase the security associated with communication of CoAP messages between any number of systems or devices. 
     Accordingly, communication of messages between systems or devices in accordance with one or more embodiments can be used in one or more applications. For example, in the context of home automation, a first computer system (e.g.,  110 ) may be used to communicate with and/or control at least one home appliance or system (e.g., a television, computer display, refrigerator, microwave, oven, door lock, security system, heating or air conditioning system, etc.). In this case, each home appliance or system may include at least one respective instance of a second computer system (e.g.,  120 ). As another example, in the context of remote data monitoring, a first computer system (e.g.,  110 ) may be used to remotely monitor at least one parameter (e.g., temperature, pressure, humidity, moisture, wind speed, etc.) measured by at least one sensor. In this case, each sensor may be included in (e.g., as at least a portion of an operational component  126 ) and/or in communication with at least one instance of a second computer system (e.g.,  120 ). The data sent to the first computer system (e.g.,  110 ) may be stored and collected (e.g., in a database), thereby allowing processing of the data (e.g., to generate business intelligence, for charting, for analytics, etc.). 
       FIGS. 6A and 6B  show a flowchart of process  600  for increasing communication security in accordance with one embodiment. As shown in  FIG. 6A , step  605  involves accessing message data. In one embodiment, the message data (e.g., accessed in step  605 ) may include at least a portion of a CoAP message (e.g.,  200 ,  500 A,  500 B, etc.) other than authentication data (e.g.,  260  of  FIG. 2 , “Authentication Data 1” of  FIG. 5A , “Authentication Data 2” of  FIG. 5B , etc.). For example, the message data may include data associated with a header (e.g., included in portion  210  of CoAP message  200 ), data associated with a token (e.g., included in portion  220  of CoAP message  200 ), data associated with at least one option (e.g., included in portion  230  of CoAP message  200 ), data associated with a payload marker (e.g., included in portion  240  of CoAP message  200 ), data associated with at least a portion of a payload (e.g., included in portion  250  of CoAP message  200 ), some combination thereof, etc. And in one embodiment, the message data (e.g., accessed in step  605 ) may include a unique identifier (e.g., associated with a sender of the CoAP message, included in portion  230  of CoAP message  200 , etc.), an authentication mechanism identifier (e.g., associated with an authentication mechanism used to generate the authentication data included in the CoAP message, included in portion  230  of CoAP message  200 , etc.), a nonce (e.g., included in portion  230  of CoAP message  200 , etc.), or some combination thereof. 
     As shown in  FIG. 6A , step  610  involves generating authentication data (e.g.,  260  of  FIG. 2 , “Authentication Data 1” of  FIG. 5A , “Authentication Data 2” of  FIG. 5B , etc.). In one embodiment, the authentication data may be generated in step  610  at a computer system (e.g., by security component  112  of computer system  110 , by security component  122  of computer system  120 , etc.) using an authentication mechanism such as HMAC, OAuth, OAuth 2.0, OpenID, etc. And in one embodiment, the authentication data (e.g.,  260  of  FIG. 2 , “Authentication Data 1” of  FIG. 5A , “Authentication Data 2” of  FIG. 5B , etc.) may be generated in step  610  based on message data (e.g., accessed in step  605 ). 
     The authentication data may be generated in step  610  based on a key in one embodiment. For example, where the authentication mechanism used to generate the authentication data in step  610  is HMAC, the authentication data may be generated by performing a hash function (e.g., MD5, SHA-1, SHA256, SHA512, etc.) on the message data (e.g., accessed in step  605 ) using a key. And in one embodiment, the CoAP message (e.g.,  200 ,  500 A,  500 B, etc.) may be free of a key used to generate the authentication data in step  610 . 
     In one embodiment, the key may be associated with the sender of the CoAP message (e.g., generated in step  620 ). For example, the key may be a secret key or private key that is unique to the sender (e.g., computer system  110 , computer system  120 , etc.). Alternatively, the key may be associated with the recipient of the CoAP message (e.g., generated in step  620 ). For example, the key may be a secret key or private key that is unique to the recipient (e.g., computer system  110 , computer system  120 , etc.). 
     Where a key associated with the sender of the CoAP message (e.g., generated in step  620 ) is used to generate the authentication data in step  610 , the key may be stored locally at the sender in one embodiment. For example, the key may be stored locally in a security component (e.g.,  112  of computer system  110 ,  122  of computer system  120 , etc.), in a memory (e.g., of computer system  110 , of computer system  120 , etc.), in a database (e.g., of computer system  110 , of computer system  120 , etc.), etc. Alternatively, the key may be stored remotely (e.g., at another system or device) and accessed by the sender in a secure manner in one embodiment. Accordingly, a key associated with the sender of the CoAP message may be accessed and used by the sender to securely generate the authentication data in step  610 . 
     Where a key associated with the recipient of the CoAP message (e.g., generated in step  620 ) is used to generate the authentication data in step  610 , the sender may access the key based on information about the recipient in one embodiment. For example, using data (e.g.,  700  of  FIG. 7 ) which correlates or maps information about systems or devices (e.g., unique identifiers) to keys, the sender (e.g., computer system  110 ) may access a key (e.g., “Key  2 ”) associated with the recipient (e.g., computer system  120 ) based on information about the recipient (e.g., the unique identifier of “cs120” associated with computer system  120 , other information associated with computer system  120 , etc.). In one embodiment, the data (e.g.,  700  of  FIG. 7 ) may be stored locally in a security component (e.g.,  112  of computer system  110 ,  122  of computer system  120 , etc.), in a memory (e.g., of computer system  110 , of computer system  120 , etc.), in a database (e.g., of computer system  110 , of computer system  120 , etc.), etc. Alternatively, the data (e.g.,  700  of  FIG. 7 ) may be stored remotely (e.g., at another system or device) and accessed by the sender in a secure manner in one embodiment. Accordingly, a key associated with the recipient of the CoAP message may be accessed and used by the sender to securely generate the authentication data in step  610 . 
     Although  FIG. 7  shows data  700  as including a particular amount of data, it should be appreciated that a different amount of data may be included in data  700  in other embodiments. Additionally, although  FIG. 7  shows data  700  as including a particular arrangement and type of data, it should be appreciated that a different arrangement and/or type of data may be included in data  700  in other embodiments. 
     The size or length of the key (e.g., used to generate the authentication data in step  610 ) may be associated with the authentication mechanism used to generate the authentication data in step  610 . For example, where the authentication mechanism of HMAC utilizing a SHA256 hash function is used to generate the authentication data, the length of the key may be 32 bytes. As another example, where the authentication mechanism of HMAC utilizing a SHA512 hash function is used to generate the authentication data, the length of the key may be 64 bytes. 
     In one embodiment, multiple CoAP messages may each include respective authentication data generated based on a key associated with a common system or device. For example, where a first CoAP message (e.g.,  500 A) is sent from a first computer system (e.g.  110 ) to a second computer system (e.g.,  120 ), and where a second CoAP message (e.g.,  500 B) is sent from the second computer system (e.g.,  120 ) to the first computer system (e.g.,  110 ), the first CoAP message (e.g.,  500 A) and the second CoAP message (e.g.,  500 B) may each include respective authentication data (e.g., “Authentication Data 1” and “Authentication Data 2”) generated based on a key associated with the first computer system (e.g.,  110 ). It should be appreciated that the authentication data (e.g., “Authentication Data 1” and “Authentication Data 2”) included in the first and second CoAP messages may be different (even though they are generated based on the same key associated with the first computer system) since the respective data or content of each CoAP message may be different. 
     As another example, where a first CoAP message (e.g.,  500 A) is sent from a first computer system (e.g.  110 ) to a second computer system (e.g.,  120 ), and where a second CoAP message (e.g.,  500 B) is sent from the second computer system (e.g.,  120 ) to the first computer system (e.g.,  110 ), the first CoAP message (e.g.,  500 A) and the second CoAP message (e.g.,  500 B) may each include respective authentication data (e.g., “Authentication Data 1” and “Authentication Data 2”) generated based on a key associated with the second computer system (e.g.,  120 ). It should be appreciated that the authentication data (e.g., “Authentication Data 1” and “Authentication Data 2”) included in the first and second CoAP messages may be different (even though they are generated based on the same key associated with the second computer system) since the respective data or content of each CoAP message may be different. 
     As shown in  FIG. 6A , step  620  involves generating a CoAP message which includes the authentication data (e.g., generated in step  610 ). The CoAP message (e.g.,  200 ,  500 A,  500 B, etc.) may be generated in step  620  using a message generation component (e.g.,  114  of the computer system  110 ,  124  of the computer system  120 , etc.) in one embodiment. And in one embodiment, step  620  may be performed in accordance with process  800  of  FIG. 8 . 
       FIG. 8  shows a flowchart of process  800  for generating a CoAP message in accordance with one embodiment. As shown in  FIG. 8 , step  810  involves accessing authentication data (e.g.,  260 , “Authentication Data 1” of CoAP message  500 A, “Authentication Data 2” of CoAP message  500 B, etc.). The authentication data accessed in step  810  may be the authentication data generated in step  610  of process  600  in one embodiment. 
     As shown in  FIG. 8 , step  820  involves generating the CoAP message (e.g.,  200 ,  500 A,  500 B, etc.) including message data (e.g., accessed in step  605 ) and the authentication data (e.g., accessed in step  810 ). The CoAP message (e.g.,  200 ,  500 A,  500 B, etc.) may be generated in step  820  using a message generation component (e.g.,  114  of computer system  110 ,  124  of computer system  120 , etc.) in one embodiment. In one embodiment, step  820  may involve formatting the message data in accordance with CoAP (e.g., into one or more portions of CoAP message  200 ). The authentication data may be included in or as the payload (e.g., associated with portion  250  of CoAP message  200 ) of the CoAP message (e.g.,  200 ,  500 A,  500 B, etc.) in one embodiment. 
     In one embodiment, step  820  may involve further including a payload marker as part of the CoAP message generation. For example, where the message data is free of data or content to be included as a payload (e.g., and therefore is also free of a payload marker), a payload marker may be included as part of the CoAP message in step  820  since the authentication data (e.g., accessed in step  810 ) may be included as the payload (e.g., the entire payload) of the CoAP message. 
     In one embodiment, step  820  may involve generating a bit stream or byte stream including the message data (e.g., accessed in step  605 ) and the authentication data (e.g., accessed in step  810 ). The bit stream or byte stream may be formatted in accordance with CoAP in one embodiment. 
     Although  FIG. 8  depicts process  800  as including a specific number of steps, it should be appreciated that process  800  may include a different number of steps in other embodiments. Although  FIG. 8  depicts process  800  as including a specific ordering of steps, it should be appreciated that process  800  may include a different ordering of steps in other embodiments. 
     Turning back to  FIG. 6A , step  630  involves communicating the CoAP message (e.g., generated in step  620  and/or in accordance with one or more steps of process  800  of  FIG. 8 ). In one embodiment, step  630  may involve communicating the CoAP message from a first computer system (e.g.,  110 ) to at least one other computer system (e.g.,  120 , one or more other systems or devices, etc.). And in one embodiment, step  630  may involve communicating the CoAP message from a second computer system (e.g.,  120 ) to at least one other computer system (e.g.,  110 , one or more other systems or devices, etc.). 
     In one embodiment, the CoAP message may be communicated in step  630  over a connection (e.g.,  130  between computer system  110  and computer system  120 ). The CoAP message may be communicated in step  630  as a bit stream or a byte stream in one embodiment. And in one embodiment, step  630  may involve communicating the CoAP message using a communication interface (e.g.,  118  of computer system  110 ,  128  of computer system  120 , etc.). 
     Accordingly, communication security can be increased by including authentication data in CoAP messages communicated between systems or devices. For example, the recipient of the CoAP message (e.g.,  200 ,  500 A,  500 B, etc.) can perform message validation with respect to the authentication data (e.g., included in the CoAP message) to verify the authenticity of the sender of the CoAP message and/or the integrity of the CoAP message. As another example, where the CoAP message (e.g.,  200 ,  500 A,  500 B, etc.) includes a nonce (e.g., in the data associated with portion  230 , in another portion of the CoAP message, etc.), communication security can be improved by allowing the recipient to detect and/or act on a replay attack. 
     As shown in  FIG. 6B , step  640  involves receiving the CoAP message (e.g.,  200 ,  500 A,  500 B, etc.). In one embodiment, step  640  may involve receiving the CoAP message at the second computer system (e.g.,  120 ) from another computer system (e.g.,  110 , another system or device, etc.). And in one embodiment, step  640  may involve receiving the CoAP message at the first computer system (e.g.,  110 ) from another computer system (e.g.,  120 , another system or device, etc.). 
     In one embodiment, the CoAP message may be received in step  640  over a connection (e.g.,  130  between computer system  110  and computer system  120 ). The CoAP message may be received in step  640  as a bit stream or a byte stream in one embodiment. And in one embodiment, step  640  may involve receiving the CoAP message using a communication interface (e.g.,  118  of computer system  110 ,  128  of computer system  120 , etc.). 
     Step  650  involves optionally processing the CoAP message (e.g., received in step  640 ). In one embodiment, step  650  may involve processing the CoAP message using a security component (e.g.,  112  of computer system  110 ,  122  of computer system  120 , etc.). And in one embodiment, step  650  may be performed in accordance with process  900  of  FIG. 9 . 
       FIG. 9  shows a flowchart of process  900  for processing a CoAP message in accordance with one embodiment. As shown in  FIG. 9 , step  910  involves accessing an authentication mechanism identifier from the CoAP message (e.g.,  200 ,  500 A,  500 B, etc.). The authentication mechanism identifier may be associated with the authentication mechanism (e.g., HMAC utilizing a MD5 hash function, HMAC utilizing a SHA-1 hash function, HMAC utilizing a SHA256 hash function, HMAC utilizing a SHA512 hash function, OAuth, OAuth 2.0, OpenID, etc.) used to generate the authentication data (e.g., in step  610  of process  600 ) in one embodiment. And in one embodiment, the authentication mechanism identifier may be accessed in step  910  from a portion of the CoAP message associated with at least one option (e.g., portion  230  of CoAP message  200 ). For example, an authentication mechanism identifier (e.g. “hs256=1” associated with, in this case, an authentication mechanism of HMAC utilizing a SHA256 hash function) may be accessed from a portion of CoAP message  500 A associated with an option value (e.g., of an option associated with a query, of a “Uri-Query” option, etc.). 
     Step  920  may involve determining the length of the authentication data (e.g.,  260 , “Authentication Data 1” of CoAP message  500 A, “Authentication Data 2” of CoAP message  500 B, etc.) based on the authentication mechanism identifier (e.g., accessed in step  910 ). For example, where the authentication mechanism identifier (e.g. “hs256=1” of CoAP message  500 A) is associated with an authentication mechanism of HMAC utilizing a SHA256 hash function, the length of the authentication data may be determined in step  920  to be 32 bytes. As another example, where the authentication mechanism identifier is associated with an authentication mechanism of HMAC utilizing a SHA512 hash function, the length of the authentication data may be determined in step  920  to be 64 bytes. 
     As shown in  FIG. 9 , step  930  involves removing a portion of the CoAP message based on the length (e.g., determined in step  920 ). The portion of the CoAP message removed in step  930  may include at least a portion of the authentication data (e.g.,  260 ). In one embodiment, the portion removed in step  930  may be a predetermined portion (e.g., the first portion, the last portion, an intermediary portion, etc.) of a payload of the CoAP message. For example, where the length of the authentication data is determined to be 32 bytes in step  920 , step  930  may involve removing the last 32 bytes of the CoAP message. 
     Step  940  involves determining whether the CoAP message is free of a payload (e.g., after removal of the portion in step  930 ). If it is determined in step  940  that at least a portion of the payload remains (e.g., the CoAP message is not free of the payload), then step  950  may be bypassed and process  900  may terminate. Alternatively, if it is determined in step  940  that the CoAP message is free of the payload (e.g., no other data or content remains after removal of the portion in step  930 ), then the payload marker (e.g., associated with portion  240  of CoAP message  200 ) may be removed from the CoAP message in step  950 . 
     Accordingly, in one embodiment, the payload marker may be removed from the CoAP message where the payload of the CoAP message (e.g., received in step  640 ) includes only the authentication data (e.g.,  260 , “Authentication Data 1” of CoAP message  500 A, “Authentication Data  2 ” of CoAP message  500 B, etc.). This may be used to account for the situation where, during message generation (e.g., in step  620  and/or in accordance with one or more steps of process  800  of  FIG. 8 ), the payload marker was included in the CoAP message since the authentication data was included as the payload (e.g., the entire payload) of the CoAP message. 
     Although  FIG. 9  depicts process  900  as including a specific number of steps, it should be appreciated that process  900  may include a different number of steps in other embodiments. Although  FIG. 9  depicts process  900  as including a specific ordering of steps, it should be appreciated that process  900  may include a different ordering of steps in other embodiments. 
     Turning back to  FIG. 6B , step  660  involves performing message validation based on the authentication data (e.g., accessed from the CoAP message in step  650  and/or in step  930 ). In one embodiment, the message validation may be used to verify the authenticity of the sender of the CoAP message (e.g.,  200 ,  500 A,  500 B, etc.) and/or the integrity of the CoAP message (e.g.,  200 ,  500 A,  500 B, etc.). Where the CoAP message (e.g.,  200 ,  500 A,  500 B, etc.) includes a nonce (e.g., in data associated with portion  230 , in another portion of the CoAP message, etc.), the message validation may be used to detect a replay attack. 
     In one embodiment, message validation may be performed in step  660  by comparing second authentication data to the authentication data (e.g., accessed from the CoAP message in step  650  and/or in step  930 ). The second authentication data may be generated (e.g., in step  660 ) based on at least a portion of the CoAP message (e.g., received in step  640 ) in one embodiment. For example, the second authentication data may be generated based on data associated with a header (e.g., included in portion  210  of CoAP message  200 ), data associated with a token (e.g., included in portion  220  of CoAP message  200 ), data associated with at least one option (e.g., included in portion  230  of CoAP message  200 ), data associated with a payload marker (e.g., included in portion  240  of CoAP message  200 ), data associated with at least a portion of a payload (e.g., included in portion  250  of CoAP message  200 ), some combination thereof, etc. As another example, the second authentication data may be generated based on at least a unique identifier (e.g., associated with a sender of the CoAP message, included in portion  230  of CoAP message  200 , etc.), an authentication mechanism identifier (e.g., associated with an authentication mechanism used to generate the authentication data included in the CoAP message and/or used to generate the second authentication data, included in portion  230  of CoAP message  200 , etc.), a nonce (e.g., included in portion  230  of CoAP message  200 , etc.), or some combination thereof. And as a further example, the second authentication data may be generated based on at least a portion of the CoAP message excluding the authentication data (e.g.,  260  of  FIG. 2 , “Authentication Data 1” of  FIG. 5A , “Authentication Data  2 ” of  FIG. 5B , etc.). 
     The second authentication data may be generated (e.g., in step  660 ) based on a key in one embodiment. For example, where the authentication mechanism used to generate the second authentication data is HMAC, the second authentication data may be generated by performing a hash function (e.g., MD5, SHA-1, SHA256, SHA512, etc.) on at least a portion of the CoAP message using a key. And in one embodiment, the CoAP message (e.g., received in step  640 ) may be free of a key used to generate the second authentication data. 
     In one embodiment, the key may be associated with the sender of the CoAP message (e.g., received in step  640 ). For example, the key may be a secret key or private key that is unique to the sender (e.g., computer system  110 , computer system  120 , etc.). Alternatively, the key may be associated with the recipient of the CoAP message (e.g., received in step  640 ). For example, the key may be a secret key or private key that is unique to the recipient (e.g., computer system  110 , computer system  120 , etc.). 
     In one embodiment, at least one attribute of the generation of the second authentication data in step  660  may be the same as at least one attribute of the generation of the authentication data (e.g., in step  610 ). For example, the second authentication data may be generated based on the same data as the authentication data, the second authentication data may be generated based on the same key as the authentication data, the second authentication data may be generated using the same authentication mechanism as the authentication data, some combination thereof, etc. 
     The message validation may be performed in step  660  using a security component (e.g.,  112  of computer system  110 ,  122  of computer system  120 , etc.) in one embodiment. And in one embodiment, step  660  may be performed in accordance with process  1000  of  FIG. 10 . 
       FIG. 10  shows a flowchart of process  1000  for performing message validation in accordance with one embodiment. As shown in  FIG. 10 , step  1010  involves accessing the authentication data (e.g.,  260  of  FIG. 2 , “Authentication Data 1” of  FIG. 5A , “Authentication Data  2 ” of  FIG. 5B , etc.). In one embodiment, the authentication data may be accessed from the CoAP message (e.g., received in step  640 ). And in one embodiment, the authentication data may be accessed from data associated with processing of the CoAP message (e.g., in step  650  and/or in accordance with one or more steps of process  900 ). For example, the authentication data may be accessed from a portion of data removed from the CoAP message (e.g., in step  930 ). 
     Step  1020  involves optionally accessing a unique identifier from the CoAP message (e.g.,  200 ,  500 A,  500 B, etc.). For example, where the CoAP message includes authentication data generated using a key associated with the sender of the CoAP message, a unique identifier (e.g., associated with the sender of the CoAP message) may be accessed from the CoAP message in step  1020  by the recipient. In one embodiment, the unique identifier may be accessed in step  1020  from a portion of the CoAP message associated with at least one option (e.g., portion  230  of CoAP message  200 ). 
     As shown in  FIG. 10 , step  1030  involves accessing a key. The key may be stored locally at the recipient in a security component (e.g.,  112  of computer system  110 ,  122  of computer system  120 , etc.), in a memory (e.g., of computer system  110 , of computer system  120 , etc.), in a database (e.g., of computer system  110 , of computer system  120 , etc.), etc. Alternatively, the key may be stored remotely (e.g., at a system or device other than the recipient) and accessed by the recipient in step  1030  in a secure manner. As such, in accordance with one or more embodiments, the key may be accessed (e.g., by the recipient) in step  1030  while limiting other access to the key (e.g., by at least one system or device other than the recipient). 
     The key may be associated with the sender of the CoAP message (e.g., received in step  640 ) in one embodiment. For example, the key may be a secret key or private key that is unique to the sender (e.g., computer system  110 , computer system  120 , etc.). Alternatively, the key may be associated with the recipient of the CoAP message (e.g., received in step  640 ). For example, the key may be a secret key or private key that is unique to the recipient (e.g., computer system  110 , computer system  120 , etc.). 
     Where the key is associated with the sender of the CoAP message, the recipient may access the key in step  1030  based on information about the sender in one embodiment. For example, the unique identifier (e.g., associated with the sender of the CoAP message) accessed in step  1020  may be used by the recipient to access the key (e.g., associated with the sender) in step  1030 . 
     In one embodiment, the recipient may access the key (e.g., associated with the sender of the CoAP message) in step  1030  using data (e.g.,  700  of  FIG. 7 ) which correlates or maps information about systems or devices (e.g., unique identifiers) to keys. The data (e.g.,  700  of  FIG. 7 ) may be stored locally at the recipient in a security component (e.g.,  112  of computer system  110 ,  122  of computer system  120 , etc.), in a memory (e.g., of computer system  110 , of computer system  120 , etc.), in a database (e.g., of computer system  110 , of computer system  120 , etc.), etc. Alternatively, the data (e.g.,  700  of  FIG. 7 ) may be stored remotely (e.g., at a system or device other than the recipient) and accessed by the recipient in a secure manner. 
     Where the key is associated with the recipient of the CoAP message, the key may be accessed locally by the recipient in step  1030  in one embodiment. For example, the key (e.g., associated with the recipient) may be accessed from local storage in a security component (e.g.,  112  of computer system  110 ,  122  of computer system  120 , etc.), in a memory (e.g., of computer system  110 , of computer system  120 , etc.), in a database (e.g., of computer system  110 , of computer system  120 , etc.), etc. Alternatively, the key (e.g., associated with the recipient) may be accessed remotely (e.g., from another system or device) in a secure manner by the recipient in step  1030  in one embodiment. 
     As shown in  FIG. 10 , step  1040  involves determining whether at least one condition for message invalidity is met. In one embodiment, step  1040  may be performed in accordance with process  1100  of  FIG. 11 . 
       FIG. 11  shows a flowchart of process  1100  for determining whether at least one condition for message invalidity is met in accordance with one embodiment. As shown in  FIG. 11 , step  1110  involves determining whether the CoAP message (e.g., received in step  640 ) includes a unique identifier. In one embodiment, step  1110  may involve determining whether the CoAP message includes a unique identifier associated with the sender (e.g., computer system  110 , computer system  120 , another system or device, etc.) of the CoAP message. And in one embodiment, step  1110  may involve determining whether a portion of the CoAP message associated with at least one option (e.g., portion  230  of CoAP message  200 ) includes a unique identifier. 
     If it is determined in step  1110  that the CoAP message does not include a unique identifier, then it may be determined in step  1120  that at least one condition for message invalidity has been met and process  1100  may terminate. Alternatively, if it is determined in step  1110  that the CoAP message includes a unique identifier, then step  1130  may be performed. 
     As shown in  FIG. 11 , step  1130  involves determining whether the CoAP message (e.g., received in step  640 ) includes a nonce. In one embodiment, step  1130  may involve determining whether a portion of the CoAP message associated with at least one option (e.g., portion  230  of CoAP message  200 ) includes a nonce. 
     If it is determined in step  1130  that the CoAP message does not include a nonce, then it may be determined in step  1120  that at least one condition for message invalidity has been met and process  1100  may terminate. Alternatively, if it is determined in step  1130  that the CoAP message includes a nonce, then step  1140  may be performed. 
     As shown in  FIG. 11 , step  1140  involves determining whether the nonce (e.g., included in the CoAP message as determined in step  1130 ) is different from a previous nonce (e.g., of a previously-transmitted or previously-received CoAP message). In one embodiment, the recipient of the CoAP message may store at least one previous nonce (e.g., from one or more previously-transmitted or previously-received CoAP messages) for comparison with the nonce of the CoAP message. 
     In one embodiment, it may be determined in step  1140  whether the nonce is different from another nonce of another CoAP message (e.g., of a previously-transmitted or previously-received CoAP message) from the same sender (e.g., corresponding to the unique identifier associated with step  1110 ). For example, the recipient of the CoAP message may store at least one previous nonce corresponding to the sender of the CoAP message for comparison with the nonce of the CoAP message. 
     In one embodiment, step  1140  may be used to increase communication security by detecting a replay attack. For example, if it is determined in step  1140  that the nonce is the same as (e.g., not different from) a previous nonce, then it may indicate a malicious re-sending of the CoAP message or that the CoAP message is otherwise associated with a replay attack. 
     If it is determined in step  1140  that the nonce is not different from a previous nonce, then it may be determined in step  1120  that at least one condition for message invalidity has been met and process  1100  may terminate. Alternatively, if it is determined in step  1140  that the nonce is different from a previous nonce, then step  1150  may be performed. 
     As shown in  FIG. 11 , step  1150  involves determining whether a payload of the CoAP message (e.g., received in step  640 ) is at least a predetermined size. In one embodiment, the predetermined size may correspond to an authentication mechanism used to generate authentication data (e.g.,  260  of  FIG. 2 , “Authentication Data 1” of  FIG. 5A , “Authentication Data 2” of  FIG. 5B , etc.) included in the CoAP message and/or an authentication mechanism identifier included in the CoAP message (e.g., in a portion of the CoAP message associated with at least one option, in portion  230  of CoAP message  200 , in another portion, etc.). 
     For example, where an authentication mechanism (e.g., used to generate the authentication data included in the CoAP message) is HMAC utilizing a SHA256 hash function and/or where an authentication mechanism identifier (e.g., included in the CoAP message) is associated with an authentication mechanism (e.g., used to generate the authentication data included in the CoAP message) of HMAC utilizing a SHA256 hash function, the predetermined size used in step  1150  may be 32 bytes. As another example, where an authentication mechanism (e.g., used to generate the authentication data included in the CoAP message) is HMAC utilizing a SHA512 hash function and/or where an authentication mechanism identifier (e.g., included in the CoAP message) is associated with an authentication mechanism (e.g., used to generate the authentication data included in the CoAP message) of HMAC utilizing a SHA512 hash function, the predetermined size used in step  1150  may be 64 bytes. 
     In one embodiment, step  1150  may be used to increase communication security by identifying one or more security risks related to authentication data of the CoAP message. For example, if it is determined in step  1150  that the payload of the CoAP message is not at least a predetermined size, then it may indicate that the CoAP message does not include any authentication data and/or that the authentication data is not proper (e.g., not of the proper size or length based on an authentication mechanism used to generate the authentication data). 
     If it is determined in step  1150  that the payload of the CoAP message is not at least a predetermined size, then it may be determined in step  1120  that at least one condition for message invalidity has been met and process  1100  may terminate. Alternatively, if it is determined in step  1150  that the payload of the CoAP message is at least a predetermined size, then step  1160  may be performed. 
     As shown in  FIG. 11 , step  1160  involves determining if a key has been accessed (e.g., in step  1030  of process  1000 ). In one embodiment, step  1160  may involve determining if a key associated with the recipient of the CoAP message has been accessed. And in one embodiment, step  1160  may involve determining if a key associated with the sender of the CoAP message has been accessed (e.g., based on a unique identifier or other information associated with the sender). 
     If it is determined in step  1160  that a key has not been accessed, then it may be determined in step  1120  that at least one condition for message invalidity has been met and process  1100  may terminate. Alternatively, if it is determined in step  1160  that a key has been accessed, then it may be determined in step  1170  that at least one condition for message invalidity has not been met and process  1100  may terminate. 
     Although  FIG. 11  depicts process  1100  as including a specific number of steps, it should be appreciated that process  1100  may include a different number of steps in other embodiments. For example, one or more steps (e.g., step  1110 ,  1130 ,  1140 ,  1150 ,  1160 , or some combination thereof) may be omitted in one or more embodiments. Although  FIG. 11  depicts process  1100  as including a specific ordering of steps, it should be appreciated that process  1100  may include a different ordering of steps in other embodiments. 
     Turning back to  FIG. 10 , if it is determined in step  1040  that at least one condition for message invalidity has been met, then it may be determined in step  1050  that the CoAP message (e.g., received in step  640 ) is invalid. Alternatively, if it is determined in step  1040  that at least one condition for message invalidity has not been met, then step  1060  may be performed. 
     As shown in  FIG. 10 , step  1060  involves generating second authentication data. In one embodiment, the second authentication data may be generated in step  1060  using an authentication mechanism such as HMAC, OAuth, OAuth 2.0, OpenID, etc. And in one embodiment, the authentication mechanism used to generate the second authentication data in step  1060  may be the same as the authentication mechanism used to generate (e.g., in step  610 ) the authentication data (e.g., included in the CoAP message received in step  640 ). 
     In one embodiment, the authentication mechanism used to generate the second authentication data in step  1060  may be determined based on an authentication mechanism identifier included in the CoAP message (e.g., in portion  230  associated with at least one option). In one embodiment, the authentication mechanism used to generate the second authentication data in step  1060  may be determined based on at least one other message (e.g., including information about an authentication mechanism used to generate the authentication data and/or the second authentication data), where the at least one other message may be separate from the CoAP message (e.g., including the authentication data) and may be communicated before or after the CoAP message. And in one embodiment, the authentication mechanism used to generate the second authentication data in step  1060  may be determined using data stored at the recipient (e.g., in security component  112  of computer system  110 , in another component of computer system  110 , in security component  122  of computer system  120 , in another component of computer system  120 , in a component of another system or device, etc.), where the data may be supplied to the recipient by another system or device. 
     In one embodiment, the second authentication data may be generated in step  1060  based on at least a portion of the CoAP message (e.g., received in step  640 ). For example, the second authentication data may be generated in step  1060  based on data associated with a header (e.g., included in portion  210  of CoAP message  200 ), data associated with a token (e.g., included in portion  220  of CoAP message  200 ), data associated with at least one option (e.g., included in portion  230  of CoAP message  200 ), data associated with a payload marker (e.g., included in portion  240  of CoAP message  200 ), data associated with at least a portion of a payload (e.g., included in portion  250  of CoAP message  200 ), some combination thereof, etc. As another example, the second authentication data may be generated in step  1060  based on at least a unique identifier (e.g., associated with a sender of the CoAP message, included in portion  230  of CoAP message  200 , etc.), an authentication mechanism identifier (e.g., associated with an authentication mechanism used to generate the authentication data included in the CoAP message and/or used to generate the second authentication data in step  1060 , included in portion  230  of CoAP message  200 , etc.), a nonce (e.g., included in portion  230  of CoAP message  200 , etc.), or some combination thereof. And as a further example, the second authentication data may be generated in step  1060  based on at least a portion of the CoAP message excluding the authentication data (e.g.,  260  of  FIG. 2 , “Authentication Data 1” of  FIG. 5A , “Authentication Data 2” of  FIG. 5B , etc.). 
     The second authentication data may be generated in step  1060  based on a key in one embodiment. For example, where the authentication mechanism used to generate the second authentication data is HMAC, the second authentication data may be generated in step  1060  by performing a hash function (e.g., MD5, SHA-1, SHA256, SHA512, etc.) on at least a portion of the CoAP message using a key (e.g., accessed in step  1030 ). And in one embodiment, the CoAP message (e.g., received in step  640 ) may be free of a key used to generate the second authentication data in step  1060 . 
     In one embodiment, the key may be associated with the sender of the CoAP message (e.g., received in step  640 ). For example, the key may be a secret key or private key that is unique to the sender (e.g., computer system  110 , computer system  120 , etc.). Alternatively, the key may be associated with the recipient of the CoAP message (e.g., received in step  640 ). For example, the key may be a secret key or private key that is unique to the recipient (e.g., computer system  110 , computer system  120 , etc.). 
     Where a key associated with the recipient of the CoAP message (e.g., received in step  640 ) is used to generate the second authentication data in step  1060 , the key may be stored locally at the recipient in one embodiment. For example, the key may be stored locally in a security component (e.g.,  112  of computer system  110 ,  122  of computer system  120 , etc.), in a memory (e.g., of computer system  110 , of computer system  120 , etc.), in a database (e.g., of computer system  110 , of computer system  120 , etc.), etc. Alternatively, the key may be stored remotely (e.g., at another system or device) and accessed by the recipient in a secure manner in one embodiment. Accordingly, a key associated with the recipient of the CoAP message may be accessed and used by the recipient to securely generate the second authentication data in step  1060 . 
     Where a key associated with the sender of the CoAP message (e.g., received in step  640 ) is used to generate the second authentication data in step  1060 , the recipient may access the key based on information about the sender in one embodiment. For example, using data (e.g.,  700  of  FIG. 7 ) which correlates or maps information about systems or devices (e.g., unique identifiers) to keys, the recipient (e.g., computer system  120 ) may access a key (e.g., “Key  1 ”) associated with the sender (e.g., computer system  110 ) based on information about the recipient (e.g., the unique identifier of “cs110” associated with computer system  110 ). In one embodiment, the data (e.g.,  700  of  FIG. 7 ) may be stored locally in a security component (e.g.,  112  of computer system  110 ,  122  of computer system  120 , etc.), in a memory (e.g., of computer system  110 , of computer system  120 , etc.), in a database (e.g., of computer system  110 , of computer system  120 , etc.), etc. Alternatively, the data (e.g.,  700  of  FIG. 7 ) may be stored remotely (e.g., at another system or device) and accessed by the recipient in a secure manner in one embodiment. Accordingly, a key associated with the sender of the CoAP message may be accessed and used by the recipient to securely generate the second authentication data in step  1060 . 
     The size or length of the key (e.g., used to generate the second authentication data in step  1060 ) may be associated with the authentication mechanism used to generate the second authentication data in step  1060 . For example, where the authentication mechanism of HMAC utilizing a SHA256 hash function is used to generate the authentication data, the length of the key may be 32 bytes. As another example, where the authentication mechanism of HMAC utilizing a SHA512 hash function is used to generate the authentication data, the length of the key may be 64 bytes. 
     As shown in  FIG. 10 , step  1070  may involve determining whether the second authentication data (e.g., generated in step  1060 ) correlates to the authentication data (e.g., included in the CoAP message received in step  640 ). If the second authentication data does not correlate to the authentication data, then it may be determined in step  1050  that the CoAP message (e.g., received in step  640 ) is invalid. Alternatively, if the second authentication data correlates to the authentication data, then it may be determined in step  1080  that the CoAP message (e.g., received in step  640 ) is valid. 
     In one embodiment, message validation (e.g., performed in accordance with one or more steps of process  1000 ) may be used to verify the authenticity of the sender of a CoAP message. For example, where the authentication data and second authentication data are each generated using at least one key (e.g., at least one secret key, at least one private key, at least one key which is accessible to authorized systems or devices, some combination thereof, etc.), the authenticity of the sender of a CoAP message may be verified if it is determined that the CoAP message is valid in step  1080 . 
     In one embodiment, message validation (e.g., performed in accordance with one or more steps of process  1000 ) may be used to verify the integrity of a CoAP message. For example, where the authentication data and second authentication data are each generated based on data included in the CoAP message (e.g., message data, other data, etc.), the integrity of the CoAP message may be verified if it is determined that the CoAP message is valid in step  1080 . 
     Although  FIG. 10  depicts process  1000  as including a specific number of steps, it should be appreciated that process  1000  may include a different number of steps in other embodiments. Although  FIG. 10  depicts process  1000  as including a specific ordering of steps, it should be appreciated that process  1000  may include a different ordering of steps in other embodiments. 
     Turning back to  FIG. 6B , if it is determined in step  670  that the CoAP message (e.g., received in step  640 ) is valid, then at least one operation associated with the CoAP message may be performed in step  680 . In one embodiment, step  680  may involve performing at least one operation using an operation component (e.g.,  116  of computer system  110 ,  126  of computer system  120 , etc.). 
     In one embodiment, the at least one operation performed in step  680  may include at least one operation associated with a method code (e.g., associated with data of portion  340  as shown in  FIG. 3 ) in the CoAP message (e.g.,  200 ,  500 A,  500 B, etc.) and/or at least one operation associated with an option (e.g., associated with data of portion  230  as shown in  FIG. 2 ) of the CoAP message (e.g.,  200 ,  500 A,  500 B, etc.). For example, where a CoAP message (e.g.,  500 A) is associated with a request to get a temperature (e.g., with a method code of “GET” and a “Uri-Path” option of “temperature” as depicted in  FIG. 5A ), the at least one operation performed in step  680  may include accessing a temperature (e.g., reading a temperature, accessing a stored temperature, etc.). In one embodiment, where the at least one operation is performed in step  680  using an operation component (e.g.,  116  of computer system  110 ,  126  of computer system  120 , etc.), the operation component may include a temperature sensor. 
     The at least one operation performed in step  680  may include communication of a second CoAP message (e.g.,  500 B) in one embodiment. For example, responsive to determining that a first CoAP message (e.g.,  200 ,  500 A, etc.) is valid (e.g., in step  670 ), the second CoAP message may be communicated in step  680  from the recipient of the first CoAP message to the sender of the first CoAP message. 
     The at least one operation performed in step  680  may include an operation associated with a request code (e.g., associated with data of portion  340  as shown in  FIG. 3 ) of the CoAP message (e.g.,  200 ,  500 A,  500 B, etc.) in one embodiment. For example, where a CoAP message (e.g.,  500 B) is associated with a response including data and/or content (e.g., with a response code of “Content” and a payload including data associated with a temperature as depicted in  FIG. 5B ), the at least one operation performed in step  680  may include processing of the data (e.g., to generate business intelligence, for charting, for analytics, etc.), performing one or more other operations, etc. 
     Alternatively, if it is determined in step  670  that the CoAP message (e.g., received in step  640 ) is not valid, then at least one other operation associated with the CoAP message may be performed in step  690 . In one embodiment, step  690  may involve performing at least one other operation using an operation component (e.g.,  116  of computer system  110 ,  126  of computer system  120 , etc.). 
     In one embodiment, step  690  may involve acting responsive to a message validation failure such as a triggering of a message invalidity condition (e.g., corresponding to one or more steps of process  1100 ), another message validation failure (e.g., determined in step  660  and/or  670 , determined in step  1070 , etc.), etc. And in one embodiment, step  690  may involve acting on a suspected or detected replay attack. 
     In one embodiment, the at least one other operation performed in step  690  may include ignoring the received CoAP message (e.g., not sending a reply to the received CoAP message, performing no further processing related to the received CoAP message, etc.). In one embodiment, the at least one other operation performed in step  690  may include limiting access to the recipient (e.g., to computer system  110  where the CoAP message is received at computer system  110 , to computer system  120  where the CoAP message is received at computer system  120 , etc.) of the sender (e.g., computer system  110 , computer system  120 , at least one other system or device, etc.). 
     In one embodiment, one or more steps of process  600  may be repeated with respect to at least one other CoAP message. For example, where a first CoAP message is generated and communicated (e.g., in accordance with one or more steps of process  600 ), at least one other CoAP message may be generated and communicated (e.g., in accordance with one or more steps of process  600 ). In one embodiment, the first CoAP message may be a request, and the at least one other CoAP message may be at least one response (e.g., related to the request of the first CoAP message). 
     Although  FIGS. 6A and 6B  depict process  600  as including a specific number of steps, it should be appreciated that process  600  may include a different number of steps in other embodiments. Although  FIGS. 6A and 6B  depict process  600  as including a specific ordering of steps, it should be appreciated that process  600  may include a different ordering of steps in other embodiments. 
       FIG. 12  shows computer system  1200  upon which one or more embodiments may be implemented. As shown in  FIG. 12 , computer system  1200  may include processor  1210 , memory  1220 , removable storage  1240 , non-removable storage  1245 , graphics processor  1250 , frame buffer  1260 , communication interface  1270 , input component  1280 , and output component  1290 . One or more embodiments may be implemented by execution of computer-readable instructions or computer-executable instructions that may reside in at least one component of computer system  1200  and which may be used as a part of a general purpose computer network. In one embodiment, computer system  1200  may be a general-purpose computer system, an embedded computer system, a laptop computer system, a hand-held computer system, a portable computer system and/or portable electronic device, a stand-alone computer system, etc. 
     In one embodiment, computer system  1200  may be used to implement computer system  110 , computer system  120 , computer system  1430  of  FIG. 14 , computer system  1440  of  FIG. 14 , another system or device configured to communicate messages (e.g., CoAP messages, other types of messages, etc.), some combination thereof, etc. And in one embodiment, one or more components of computer system  1200  may be disposed in and/or coupled with a housing or enclosure. 
     In one embodiment, computer system  1200  may include at least one processor (e.g.,  1210 ) and at least one memory (e.g.,  1220 ). Processor  1210  may be or include a central processing unit (CPU) or other type of processor. Depending on the configuration and/or type of computer system environment, memory  1220  may be or include volatile memory (e.g., RAM), non-volatile memory (e.g., ROM, flash memory, etc.), some combination thereof, etc. Additionally, memory  1220  may be removable, non-removable, etc. 
     In one embodiment, computer system  1200  may include additional storage (e.g., removable storage  1240 , non-removable storage  1245 , etc.). Removable storage  1240  and/or non-removable storage  1245  may include volatile memory, non-volatile memory, some combination thereof, etc. Additionally, removable storage  1240  and/or non-removable storage  1245  may include CD-ROM, digital versatile disks (DVD), other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage, other magnetic storage devices, or any other medium which can be used to store information for access by computer system  1200 . 
     As shown in  FIG. 12 , computer system  1200  may communicate with other systems, components, or devices via communication interface  1270 . Communication interface  1270  may be used to implement at least one communication interface (e.g.,  118 ,  128 , etc.) of one or more components of system  100  in one embodiment. 
     Communication interface  1270  may embody computer-readable instructions, data structures, program modules or other data in a modulated data signal (e.g., a carrier wave) or other transport mechanism By way of example, and not limitation, communication interface  1270  may couple to and/or communicate over wired media (e.g., a wired network, direct-wired connection, etc.) and/or wireless media (e.g., a wireless network, a wireless connection utilizing acoustic, RF, infrared, or other wireless signaling, etc.). 
     Communication interface  1270  may also couple computer system  1200  to one or more external input components (e.g., a keyboard, a mouse, a trackball, a joystick, a pen, a voice input device, a touch input device, etc.). In one embodiment, communication interface  1270  may couple computer system  1200  to one or more external output components (e.g., a display, a speaker, a printer, etc.). And in one embodiment, communication interface  1270  may include a plug, receptacle, cable, slot or any other component capable of coupling to and/or communicating with another component, device, system, etc. 
     Input component  1280  may include any component capable of receiving or allowing the input of information. For example, input component  1280  may be or include a keyboard, at least one button or key, a mouse, a trackball, a joystick, a pen, a voice input device, a touch input device, another type of input component, etc. Output component  1290  may include any component capable of transmitting or allowing the output of information. For example, output component  1290  may be or include a display, a speaker, a printer, another type of output component, etc. 
     As shown in  FIG. 12 , graphics processor  1250  may perform graphics processing operations on graphical data stored in frame buffer  1260  or another memory (e.g.,  1220 ,  1240 ,  1245 , etc.) of computer system  1200 . Graphical data stored in frame buffer  1260  may be accessed, processed, and/or modified by components (e.g., graphics processor  1250 , processor  1210 , some combination thereof, etc.) of computer system  1200  and/or components of other systems, other devices, etc. Additionally, the graphical data may be accessed (e.g., by graphics processor  1250 ) and displayed on an output device coupled to computer system  1200  in one embodiment. 
     In one embodiment, a memory of computer system  1200  (e.g., memory  1220 , removable storage  1240 , non-removable storage  1245 , frame buffer  1260 , some combination thereof, etc.) may be a computer-readable medium (or computer-usable medium, or computer-readable storage medium, etc.) and may include instructions that when executed by a processor (e.g.,  1210 ,  1250 , etc.) implement a method of increasing communication security (e.g., in accordance with process  600  of  FIGS. 6A and 6B , process  1300  of  FIGS. 13A and 13B , process  3000  of  FIGS. 30A, 30B, and 30C , etc.), generating a CoAP message (e.g., in accordance with process  800  of  FIG. 8 ), processing a CoAP message (e.g., in accordance with process  900  of  FIG. 9 ), performing message validation (e.g., in accordance with process  1000  of  FIG. 10 , process  2800  of  FIG. 28 , etc.), determining whether at least one condition for message invalidity is met (e.g., in accordance with process  1100  of  FIG. 11 ), configuring permissions (e.g., in accordance with process  1500  of  FIG. 15 ), generating a message associated with communication between a plurality of computer systems (e.g., in accordance with process  1800  of  FIG. 18 ), performing processing associated with a message (e.g., in accordance with process  2000  of  FIGS. 20A and 20B , process  2200  of  FIG. 22 , process  2600  of  FIGS. 26A and 26B , etc.), generating a message including a data portion associated with a security token (e.g., in accordance with process  2500  of  FIG. 25 ), generating a message associated with successful access of a session key (e.g., in accordance with process  2900  of  FIG. 29 ), some combination thereof, etc. And in one embodiment, a computer-readable medium of computer system  1200  may be implemented in and/or using at least one die of at least one integrated circuit (e.g., at least one application-specific integrated circuit (ASIC), at least one system-on-a-chip (SOC), at least one programmable system-on-a-chip (PSOC), another type of integrated circuit, etc.). 
       FIGS. 13A and 13B  show a flowchart of process  1300  for increasing communication security in accordance with one embodiment.  FIG. 14  will be described in conjunction with  FIGS. 13A and 13B . 
     As shown in  FIG. 13A , step  1305  involves configuring permissions for a first computer system with respect to a second computer system. In one embodiment, step  1305  may involve configuring permissions for a first computer system (e.g.,  110  as shown in  FIG. 14 ) with respect to a second computer system (e.g.,  120  as shown in  FIG. 14 ) using a third computer system (e.g., computer system  1430  of  FIG. 14 ). Step  1305  may be performed using a security component (e.g.,  1432  of computer system  1430 ) in one embodiment. And in one embodiment, step  1305  may be performed in accordance with one or more steps of process  1500  of  FIG. 15 . 
       FIG. 15  shows a flowchart of process  1500  for configuring permissions in accordance with one embodiment. As shown in  FIG. 15 , step  1510  involves accessing first registration data associated with a first computer system. For example, first registration data associated with the first computer system (e.g.,  110 ) may be accessed by the third computer system (e.g.,  1430 ) in step  1510 . The first registration data may include a unique identifier associated with the first computer system, credentials or other information associated with the first computer system, etc. 
     Step  1510  may involve communicating the first registration data from the computer system being registered in one embodiment. For example, first registration data associated with the first computer system may be communicated from the first computer system (e.g.,  110 ) to the third computer system (e.g.,  1430 ). In one embodiment, registration data may be communicated between the first and third computer systems over connection  1415 . 
     Alternatively, step  1510  may involve communicating the first registration data from a computer system other than the computer system being registered. For example, first registration data associated with the first computer system may be communicated from a fourth computer system (e.g., computer system  1440 ) to the third computer system (e.g.,  1430 ). The fourth computer system (e.g.,  1440 ) may be operated by the owner of, or a user associated with, the first computer system (e.g.,  110 ) in one embodiment. In one embodiment, registration data may be communicated in step  1510  between the third and fourth computer systems over connection  1445 . And in one embodiment, step  1510  may be performed using a security component (e.g.,  1432 ), a communication interface (e.g.,  1438 ), some combination thereof, etc. 
     As shown in  FIG. 15 , step  1520  involves accessing second registration data associated with a second computer system. For example, second registration data associated with the second computer system (e.g.,  120 ) may be accessed by the third computer system (e.g.,  1430 ) in step  1520 . The second registration data may include a unique identifier associated with the second computer system, credentials or other information associated with the second computer system, etc. 
     Step  1520  may involve communicating the second registration data from the computer system being registered in one embodiment. For example, second registration data associated with the second computer system may be communicated from the second computer system (e.g.,  120 ) to the third computer system (e.g.,  1430 ). In one embodiment, registration data may be communicated between the second and third computer systems over connection  1425 . 
     Alternatively, step  1520  may involve communicating the second registration data from a computer system other than the computer system being registered. For example, second registration data associated with the second computer system may be communicated from the fourth computer system (e.g.,  1440 ) to the third computer system (e.g.,  1430 ). The fourth computer system (e.g.,  1440 ) may be operated by the owner of, or a user associated with, the second computer system (e.g.,  120 ) in one embodiment. In one embodiment, registration data may be communicated in step  1520  between the third and fourth computer systems over connection  1445 . And in one embodiment, step  1520  may be performed using a security component (e.g.,  1432 ), a communication interface (e.g.,  1438 ), some combination thereof, etc. 
     In one embodiment, the registration data (e.g., the first registration data accessed in step  1510 , the second registration data accessed in step  1520 , some combination thereof, etc.) may be manually input by a user. For example, the registration data may be manually input using the first computer system (e.g.,  110 ), where the first computer system may communicate the registration data to the third computer system (e.g.,  1430 ). As another example, the registration data may be manually input using the second computer system (e.g.,  120 ), where the second computer system may communicate the registration data to the third computer system (e.g.,  1430 ). As another example, the registration data may be manually input using a fourth computer system (e.g.,  1440 ), where the fourth computer system may communicate the registration data to the third computer system (e.g.,  1430 ). In this example, the fourth computer system (e.g.,  1440 ) may be operated by the owner of, or a user associated with, the first computer system (e.g.,  110 ) and/or the second computer system (e.g.,  120 ). And as yet another example, the registration data may be manually input using the third computer system (e.g.,  1430 ). 
     In one embodiment, step  1510  and/or step  1520  may involve performing a registration of at least one computer system. For example, registration of a first computer system (e.g.,  110 ) may be performed (e.g., using the third computer system or computer system  1430 ) in step  1510  by accessing and/or communicating registration data associated with the first computer system. As another example, registration of a second computer system (e.g.,  120 ) may be performed (e.g., using the third computer system or computer system  1430 ) in step  1520  by accessing and/or communicating registration data associated with the second computer system. 
     As shown in  FIG. 15 , step  1530  involves accessing permissions data associated with permissions for the first computer system (e.g.,  110 ). The permissions data may be accessed in step  1530  at the third computer system (e.g.,  1430 ) in one embodiment. And in one embodiment, step  1530  may be performed using a security component (e.g.,  1432 ), a communication interface (e.g.,  1438 ), some combination thereof, etc. 
     The permissions data accessed in step  1530  may be associated with a request to allow the first computer system to communicate with the second computer system in one embodiment. The request may be from the second computer system (e.g.,  120 ), from another computer system or device associated therewith, etc. 
     In one embodiment, the permissions data accessed in step  1530  may be associated with an approval of access provided responsive to a request for access. For example, responsive to a request for access of the first computer system (e.g.,  110 ) to the second computer system (e.g.,  120 ), the permissions data accessed in step  1530  may be associated with an approval of access to the second computer system (e.g.,  120 ) by the first computer system (e.g.,  110 ). In one embodiment, the request for access may be from the first computer system (e.g.,  110 ) or from another computer system associated therewith, while the approval of access may be from the second computer system (e.g.,  120 ) or from another computer system associated therewith. 
     As shown in  FIG. 15 , step  1540  involves configuring, based on the permissions data, permissions for the first computer system with respect to the second computer system. Configuration of permissions may be performed in step  1540  at the third computer system (e.g.,  1430 ) in one embodiment. And in one embodiment, step  1540  may be performed using a security component (e.g.,  1432 ). 
     For example, the third computer system (e.g.,  1430 ) may configure permissions for the first computer system in step  1540 , thereby allowing the first computer system to communicate with and/or connect to the second computer system. In this case, the permissions data (e.g., used to configure permissions for the first computer system) may be a request to allow the first computer system to communicate with the second computer system, or alternatively, the permissions data may be an approval of access (e.g., to the second computer system by the first computer system) provided responsive to a request for access (e.g., of the first computer system to the second computer system). In this manner, the third computer system (e.g.,  1430 ) may handle permissions management or access control for the first computer system (e.g.,  110 ), the second computer system (e.g.,  120 ), at least one other computer system, etc. 
     The permissions data (e.g., accessed in step  1530  and/or used to configure permissions for the first computer system in step  1540 ) may be manually input by a user in one embodiment. For example, the permissions data may be manually input using the third computer system (e.g.,  1430 ). As another example, the permissions data may be manually input using a fourth computer system (e.g.,  1440 ), where the fourth computer system may communicate the permissions data to the third computer system (e.g.,  1430 ). In this example, the fourth computer system (e.g.,  1440 ) may be operated by the owner of, or a user associated with, the second computer system (e.g.,  120 ). And as yet another example, the permissions data may be manually input using the second computer system (e.g.,  120 ), where the second computer system may communicate the permissions data to the third computer system (e.g.,  1430 ). 
       FIG. 16  shows permissions configuration data  1600  in accordance with one embodiment. Permissions configuration data (e.g.,  1600 ) may be stored at or accessible to the third computer system (e.g.,  1430 ) in one embodiment. 
     As shown in  FIG. 16 , permissions configuration data  1600  may include a correlation or mapping of at least one computer system (e.g., in column  1620 ) that is authorized to communicate with and/or connect to at least one other computer system (e.g., in column  1610 ). For example, a first set of computer systems (e.g., corresponding to the unique identifiers of “cs110,” “cs130,” and “cs140”) may be authorized to communicate with and/or connect to at least one other computer system (e.g., corresponding to the unique identifier of “cs120”). As another example, a second set of computer systems (e.g., corresponding to the unique identifiers of “cs110” and “cs160”) may be authorized to communicate with and/or connect to at least one other computer system (e.g., corresponding to the unique identifier of “cs150”). And as yet another example, a particular computer system (e.g., corresponding to the unique identifier of “cs110”) may be authorized to communicate with and/or connect to at least one other computer system (e.g., corresponding to the unique identifier of “cs170”). 
     In one embodiment, the unique identifiers in column  1610  may be associated with target systems, and the unique identifiers in column  1620  may be associated with caller systems. In this manner, permissions configuration data  1600  may include a correlation or mapping of at least one caller system (e.g., in column  1620 ) that is authorized to communicate with and/or connect to at least one target system (e.g., in column  1610 ). 
     Permissions configuration data (e.g.,  1600 ) may be generated or updated as a result of permission configuration in step  1540  of process  1500  in one embodiment. For example, where permission configuration data already exists for the second computer system (e.g., corresponding to the unique identifier “cs120”), a unique identifier (e.g., “cs110”) corresponding to the first computer system (e.g.,  110 ) may be added in step  1540  to a list of at least one other unique identifier (e.g., “cs130,” “cs140,” etc.) corresponding to at least one other computer system that is authorized to communicate with and/or connect to the second computer system (e.g.,  120 ). As another example, where permission configuration data does not yet exist for the second computer system (e.g.,  120 ), permission configuration data may be generated in step  1540  that includes a correlation or mapping between at least a first unique identifier (e.g., “cs110”) corresponding to the first computer system (e.g.,  110 ) and a second unique identifier (e.g., “cs120”) corresponding to the second computer system (e.g.,  120 ). 
     Although  FIG. 16  shows permissions configuration data  1600  as including a particular amount of data, it should be appreciated that a different amount of data may be included in permissions configuration data  1600  in other embodiments. Additionally, although  FIG. 16  shows permissions configuration data  1600  as including a particular arrangement and type of data, it should be appreciated that a different arrangement and/or type of data may be included in permissions configuration data  1600  in other embodiments. 
     Although  FIG. 15  depicts process  1500  as including a specific number of steps, it should be appreciated that process  1500  may include a different number of steps in other embodiments. Although  FIG. 15  depicts process  1500  as including a specific ordering of steps, it should be appreciated that process  1500  may include a different ordering of steps in other embodiments. 
     Turning back to  FIG. 14 , communication interface  1438  may be used to implement at least one connection (e.g.,  1415 ,  1425 ,  1445 , etc.). Communication interface  1438  may include hardware and/or software allowing at least one connection (e.g.,  1415 ,  1425 ,  1445 , etc.) to be established and allowing communication of at least one message over the at least one connection. Communication interface  1438  may allow unidirectional communication and/or bidirectional communication over at least one connection (e.g.,  1415 ,  1425 ,  1445 , etc.) with at least one other computer system (e.g.,  110 ,  120 ,  1440 , etc.) in one embodiment. And in one embodiment, communication interface  1438  may allow contemporaneous (or simultaneous) bidirectional communication (e.g. “full-duplex” communication) over at least one connection (e.g.,  1415 ,  1425 ,  1445 , etc.) with at least one other computer system (e.g.,  110 ,  120 ,  1440 , etc.). 
     At least one connection of system  1400  (e.g., connection  130 , connection  1415 , connection  1425 , connection  1445 , some combination thereof, etc.) may be or include a wired connection in one embodiment. For example, at least one connection (e.g.,  130 ,  1415 ,  1425 ,  1445 , some combination thereof, etc.) may be or include a IEEE 1394 or FireWire® connection, PCI Express® connection, Ethernet connection, SATA connection, eSATA connection, RS-232 connection, I2C connection, etc. In one embodiment, at least one connection of system  1400  (e.g., connection  130 , connection  1415 , connection  1425 , connection  1445 , some combination thereof, etc.) may be or include a wireless connection such as a Bluetooth® connection, Near Field Communication (NFC) connection, infrared (IR) connection, IEEE 802.XX connection, cellular connection, etc. And in one embodiment, at least one connection of system  1400  (e.g., connection  130 , connection  1415 , connection  1425 , connection  1445 , some combination thereof, etc.) may be or include the Internet. 
     In one embodiment, the first computer system (e.g.,  110 ) may be a client within system  1400 , and the second computer system (e.g.,  120 ) may be a server within system  1400 . And in one embodiment, the first computer system (e.g.,  110 ) may be the “caller” system within system  1400 , and the second computer system (e.g.,  120 ) may be the “target” system within system  1400 . 
     Turning back to  FIG. 13A , step  1310  involves generating a first message associated with communication between the first computer system (e.g.,  110 ) and the second computer system (e.g.,  120 ). For example, the first message may include data associated with a request from the first computer system (e.g.,  110 ) to communicate with and/or connect to the second computer system (e.g.,  120 ). As another example, the first message may include data associated with a request by the first computer system (e.g.,  110 ) for a security token and/or session key (or at least one instance thereof) from the third computer system (e.g.,  1430 ), where the security token and/or session key (or at least one instance thereof) may relate to communication between the first and second computer systems. And in one embodiment, the first message may include data associated with a target system (e.g., the second computer system or computer system  120 ) corresponding to the request of the first message, where the data associated with the target system may be or include a unique identifier associated with the target system. 
     In one embodiment, step  1310  may involve generating the first message at the first computer system (e.g.,  110 ). And in one embodiment, step  1310  may be performed using a message generation component (e.g.,  114  of computer system  110 ), a security component (e.g.,  112  of computer system  110 ), some combination thereof, etc. 
     The first message may be a CoAP message (e.g.,  1700 A of  FIG. 17A ) in one embodiment. The CoAP message (e.g.,  1700 A) may include data associated with a request from the first computer system (e.g.,  110 ) to communicate with and/or connect to the second computer system (e.g.,  120 ), a request by the first computer system (e.g.,  110 ) for a security token and/or session key (or at least one instance thereof) from the third computer system (e.g.,  1430 ), some combination thereof, etc. For example, the data associated with the request may be included in the CoAP message as an option associated with a query (e.g., a “Uri-Query” option with an option value of “communicationrequest” as depicted in  FIG. 17A ). 
     In one embodiment, the CoAP message (e.g.,  1700 A) may include data associated with a target system (e.g., a unique identifier associated with the target system) corresponding to the data associated with the request. For example, the data associated with the target system (e.g., the second computer system or computer system  120 ) may be included in the CoAP message as an option associated with a query (e.g., a “Uri-Query” option with an option value of “tid=cs120” as depicted in  FIG. 17A ). As such, where “cs120” is a unique identifier associated with the second computer system (e.g.,  120 ), the CoAP message (e.g.,  1700 A) may indicate a request from the first computer system (e.g.,  110 ) to communicate with the second computer system (e.g.,  120 ), a request from the first computer system (e.g.,  110 ) to connect to the second computer system (e.g.,  120 ), a request from the first computer system (e.g.,  110 ) for a security token associated with communication with the second computer system (e.g.,  120 ), a request from the first computer system (e.g.,  110 ) for a session key (or at least one instance thereof) associated with communication with the second computer system (e.g.,  120 ), some combination thereof, etc. 
       FIG. 17A  shows CoAP message  1700 A associated with communication between a first computer system (e.g.,  110 ) and a second computer system (e.g.,  120 ) in accordance with one embodiment. As shown in  FIG. 17A , CoAP message  1700 A may include data associated with a header, where the data associated with the header includes data associated with a version (e.g., “1”), a message type (e.g., “CON” or confirmable), a token length (e.g., “1” associated with a length of 1 byte), a code (e.g., a method code of “GET”), and a message identifier (e.g., “0x7d34”). Data associated with a token (e.g., “0x72”) may also be included in CoAP message  1700 A. 
     CoAP message  1700 A may include data associated with at least one option. For example, CoAP message  1700 A may include data associated with a host (e.g., an option value of “www.example.com”), data associated with a port (e.g., an option value of “5683”), data associated with a path (e.g., an option value of “communicationrequest”), some combination thereof, etc. In this case, at least one option associated with CoAP message  1700 A may correspond to a URI of “coap://www.example.com:5683/communicationrequest”, “coap://www.example.com/communicationrequest”, “coaps://www.example.com:5683/communicationrequest”, “coaps://www.example.comkommunicationrequest”, some combination thereof, etc. 
     The URI corresponding to at least one option associated with CoAP message  1700 A may be specific or unique to the third computer system (e.g.,  1430 ) in one embodiment. And in one embodiment, data associated with a path (e.g., an option value of “communicationrequest”, at least one other option value, etc.) of CoAP message  1700 A may be specific or unique to the third computer system (e.g.,  1430 ). 
     As another example, CoAP message  1700 A may include data associated with a max-age value (e.g., an option value of “0”). In this case, a max-age value of “0” may be used to indicate that CoAP message  1700 A is not to be cached by an intermediary system or device (e.g., situated between the sender of the CoAP message  1700 A and the ultimate recipient of the CoAP message  1700 A) such as a proxy server or other type of computer system or device. 
     As a further example, CoAP message  1700 A may include data associated with a query (e.g., including one or more parameters). An option value of “tid=cs120” (e.g., associated with a first parameter) may be associated with a unique identifier (e.g., “cs120”) of a target system (e.g., the second computer system or computer system  120 ). An option value of “uid=cs110” (e.g., associated with a second parameter) may be associated with a unique identifier (e.g., “cs110”) of a sender of CoAP message  1700 A and/or a caller system (e.g., the first computer system or computer system  110 ). An option value of “hs256=1” (e.g., associated with a third parameter) may be associated with an authentication mechanism (e.g., HMAC utilizing a hash function of SHA256) used to generate the authentication data (e.g., “Authentication Data A”) included in CoAP message  1700 A. An option value of “nonce=1” (e.g., associated with a fourth parameter) may be associated with a nonce (e.g., with a value of “1”) included in CoAP message  1700 A. 
     In one embodiment, one or more portions of CoAP message  1700 A may be associated with a URI including at least one parameter of a query. For example, CoAP message  1700 A may be associated with a URI of “coap://www.example.com:5683/communicationrequest?tid=cs120&amp;uid=cs110&amp;hs256=1&amp;nonce=1”, “coap://www.example.com/communicationrequest?tid=cs120&amp;uid=cs110&amp;hs256=1&amp;nonce=1”, “coaps://www.example.com:5683/communicationrequest?tid=cs120&amp;uid=cs110&amp;hs256=1&amp;nonce=1”, “coaps://www.example.com/communicationrequest?tid=cs120&amp;uid=cs110&amp;hs256=1&amp;nonce=1”, some combination thereof, etc. 
     CoAP message  1700 A may include data associated with at least one option length. For example, CoAP message  1700 A may include data associated with a first option length (e.g., 15 bytes) corresponding to data associated with a first option value (e.g., “www.example.com”), a second option length (e.g., 2 bytes) corresponding to data associated with a second option value (e.g., “5683”), a third option length (e.g., 20 bytes) corresponding to data associated with a third option value (e.g., “communicationrequest”), etc. 
     As shown in  FIG. 17A , CoAP message  1700 A may include data associated with at least one option identifier. The at least one option identifier may include data associated with an option number and/or an option delta in one embodiment. For example, CoAP message  1700 A may include data associated with a first numerical value (e.g., “3”) as a first option identifier corresponding to a first option (e.g., associated with a host), where the first numerical value (e.g., “3”) may be the delta or difference between the current option number (e.g., “3”) and the option number of the preceding option (e.g., “0” in this case since this is the first option). As such, the first numerical value of “3” may correspond to an option number of “3.” 
     As another example, CoAP message  1700 A may include data associated with a second numerical value (e.g., “4”) as a second option identifier corresponding to a second option (e.g., associated with a port), where the second numerical value (e.g., “4”) may be the delta or difference between the current option number (e.g., “7”) and the option number of the preceding option (e.g., “3”). As such, the second numerical value of “4” may correspond to an option number of “7.” 
     As a further example, CoAP message  1700 A may include data associated with a third numerical value (e.g., “4”) as a third option identifier corresponding to a third option (e.g., associated with a path), where the third numerical value (e.g., “4”) may be the delta or difference between the current option number (e.g., “11”) and the option number of the preceding option (e.g., “7”). As such, the third numerical value of “4” may correspond to an option number of “11.” 
     As shown in  FIG. 17A , CoAP message  1700 A may include data associated with a payload marker (e.g., “0xFF”). CoAP message  1700 A may include data associated with a payload, where the data associated with a payload may include authentication data (e.g., “Authentication Data A”). 
     Although  FIG. 17A  shows CoAP message  1700 A with a specific number and type of portions, it should be appreciated that CoAP message  1700 A may include a different number and/or type of portions in other embodiments. For example, CoAP message  1700 A may include fewer portions or at least one additional portion. As another example, a plurality of portions of CoAP message  1700 A may be combined into a smaller number of portions. Although  FIG. 17A  shows CoAP message  1700 A with a specific organization of portions, it should be appreciated that CoAP message  1700 A may include a different organization of portions in other embodiments. 
     In one embodiment, data associated with at least one option may be excluded from CoAP message  1700 A. For example, data (e.g., associated with a host, a port, a path, a max-age value, or some combination thereof) used by intermediary systems or devices (e.g., situated between the sender of CoAP message  1700 A and the ultimate recipient of CoAP message  1700 A) such as a proxy server or other type of computer system or device may be excluded in one or more embodiments where intermediary systems or devices do not exist or are unlikely to exist. 
     Turning back to  FIG. 13A , the first message may include authentication data in one embodiment. In this case, step  1310  may be performed in accordance with process  1800  of  FIG. 18 . 
       FIG. 18  shows a flowchart of process  1800  for generating a message associated with communication between a plurality of computer systems in accordance with one embodiment. One or more steps of process  1800  may be performed at or by a caller system (e.g., the first computer system or computer system  110 ) in one embodiment. 
     As shown in  FIG. 18 , step  1810  involves accessing message data associated with communication between a caller system (e.g., the first computer system or computer system  110 ) and a target system (e.g., the second computer system or computer system  120 ). In one embodiment, step  1810  may be performed using a message generation component (e.g.,  114  of computer system  110 ). 
     In one embodiment, the message data may include data associated with a request from the caller system (e.g., the first computer system or computer system  110 ) to communicate with and/or connect to the target system (e.g., the second computer system or computer system  120 ), a request by the caller system (e.g., the first computer system or computer system  110 ) for a security token and/or session key (or at least one instance thereof) from the third computer system (e.g.,  1430 ), some combination thereof, etc. For example, where the first message is a CoAP message (e.g.,  1700 A), the message data accessed in step  1810  may include data associated with an option (e.g., a “Uri-Query” option with an option value of “communicationrequest”) that identifies the request. 
     The message data may include data associated with a target system (e.g., a unique identifier associated with the target system) corresponding to the request in one embodiment. For example, where the first message is a CoAP message (e.g.,  1700 A), the message data accessed in step  1810  may include data associated with an option (e.g., a “Uri-Query” option with an option value of “tid=cs120”) that identifies the target system corresponding to the data associated with the request. 
     In one embodiment, the message data accessed in step  1810  may include data other than authentication data. For example, the message data may include data associated with a header (e.g., included in portion  210  of CoAP message  200 ), data associated with a token (e.g., included in portion  220  of CoAP message  200 ), data associated with at least one option (e.g., included in portion  230  of CoAP message  200 ), data associated with a payload marker (e.g., included in portion  240  of CoAP message  200 ), data associated with at least a portion of a payload (e.g., included in portion  250  of CoAP message  200 ), data other than the authentication data (e.g., “Authentication Data A” of CoAP message  1700 A), some combination thereof, etc. 
     As shown in  FIG. 18 , step  1820  involves generating authentication data. In one embodiment, step  1820  may be performed using a security component (e.g.,  112  of computer system  110 ). 
     In one embodiment, the authentication data may be generated in step  1820  using an authentication mechanism such as HMAC, OAuth, OAuth 2.0, OpenID, etc. The authentication data may be generated in step  1820  using a key in one embodiment. For example, where the authentication mechanism used to generate the authentication data in step  1820  is HMAC, the authentication data may be generated by performing a hash function (e.g., MD5, SHA-1, SHA256, SHA512, etc.) on message data (e.g., accessed in step  1810 ) using a key. And in one embodiment, the message data may be free of the key used to generate the authentication data in step  1820 . 
     A key associated with the caller system (e.g., the first computer system or computer system  110 ) may be used to generate the authentication data in step  1820  in one embodiment. For example, the key may be a secret key or private key that is unique to the caller system (e.g., the first computer system or computer system  110 ). The key may be stored locally at the first computer system (e.g.,  110 ) in one embodiment. For example, the key may be stored locally in a security component (e.g.,  112  of computer system  110 ), in a memory (e.g., of computer system  110 ), in a database (e.g., of computer system  110 ), etc. Alternatively, the key may be stored remotely (e.g., at another system or device) and accessed by the first computer system (e.g.,  110 ) in a secure manner in one embodiment. Accordingly, a key associated with the caller system (e.g., the first computer system or computer system  110 ) may be securely accessed and used by the caller system to generate the authentication data in step  1820  in one embodiment. 
     As shown in  FIG. 18 , step  1830  involves generating a message including the message data (e.g., accessed in step  1810 ) and the authentication data (e.g., generated in step  1820 ). In one embodiment, step  1830  may be performed using a message generation component (e.g.,  114  of computer system  110 ). 
     In one embodiment, where the message generated in step  1830  is a CoAP message (e.g.,  1700 A), step  1830  may involve formatting the message data (e.g., accessed in step  1810 ) in accordance with CoAP (e.g., into one or more portions of CoAP message  200 ). The authentication data (e.g., generated in step  1820 ) may be included in or as the payload (e.g., associated with portion  250  of CoAP message  200 ) of the CoAP message in one embodiment. For example, as shown in  FIG. 17A , authentication data (e.g., “Authentication Data A”) may be included in or as the payload of CoAP message  1700 A. 
     Step  1830  may involve including a payload marker as part of the message in one embodiment. For example, where the message data (e.g., accessed in step  1810 ) is free of data or content to be included as a payload (e.g., and therefore is also free of a payload marker), a payload marker may be included as part of the message in step  1830  since the authentication data (e.g., generated in step  1820 ) may be included as the payload (e.g., the entire payload) of the message. 
     In one embodiment, step  1830  may involve generating a bit stream or byte stream including the message data (e.g., accessed in step  1810 ) and the authentication data (e.g., generated in step  1820 ). The bit stream or byte stream may be formatted in accordance with CoAP in one embodiment. 
     Although  FIG. 18  depicts process  1800  as including a specific number of steps, it should be appreciated that process  1800  may include a different number of steps in other embodiments. Although  FIG. 18  depicts process  1800  as including a specific ordering of steps, it should be appreciated that process  1800  may include a different ordering of steps in other embodiments. 
     Turning back to  FIG. 13A , step  1315  involves communicating the first message (e.g., generated in step  1310  and/or in accordance with one or more steps of process  1800  of  FIG. 18 ) from the first computer system (e.g.,  110 ) to a third computer system (e.g.,  1430 ). In one embodiment, the first message may be communicated in step  1315  over a connection (e.g.,  1415  between computer system  110  and computer system  1430 ). The first message may be communicated in step  1315  as a bit stream or a byte stream in one embodiment. And in one embodiment, step  1315  may involve communicating the first message using at least one communication interface (e.g.,  118  of computer system  110 ,  1438  of computer system  1430 , etc.). 
     In one embodiment, step  1315  may involve communicating the first message using Datagram Transport Layer Security (DTLS). For example, where the first message is a CoAP message (e.g.,  1700 A), step  1315  may involve communicating the first message over CoAP using DTLS. 
     As shown in  FIG. 13A , step  1320  involves performing first processing associated with the first message, and responsive thereto, generating a second message including a first data portion associated with a security token and a second data portion including an instance of a session key. In one embodiment, step  1320  may involve performing the first processing associated with the first message at the third computer system (e.g.,  1430 ). For example, responsive to receiving the first message (e.g., generated in step  1310  and communicated in step  1315 ), the third computer system (e.g.,  1430 ) may determine whether the first computer system (e.g.,  110 ) is authorized to communicate with and/or connect to the second computer system (e.g.,  120 ). As another example, responsive to receiving the first message (e.g., generated in step  1310  and communicated in step  1315 ), the third computer system (e.g.,  1430 ) may perform message validation. And in one embodiment, the first processing may be performed using a security component (e.g.,  1432 ). 
     Determination of whether the first computer system (e.g.,  110 ) is authorized to communicate with and/or connect to the second computer system (e.g.,  120 ) may be performed in step  1320  based on permissions configuration data (e.g.,  1600  of  FIG. 16 , generated and/or updated in step  1305 , generated and/or updated in step  1540  of process  1500 , etc.) in one embodiment. For example, permissions configuration data may be accessed (e.g., using data included in the first message such as a unique identifier associated with the first computer system, a unique identifier associated with the second computer system, etc.) to determine whether the first computer system (e.g.,  110 ) is authorized to communicate with and/or connect to the second computer system (e.g.,  120 ). In one embodiment, the permissions configuration data may be stored at the third computer system (e.g.,  1430 ), stored remotely and accessible to the third computer system (e.g.,  1430 ), etc. 
     Where the first message includes authentication data, message validation may be performed in step  1320  based on the authentication data. For example, the third computer system (e.g.,  1430 ) may generate second authentication data based on at least a portion of the first message (e.g., a header, a token, at least one option, a payload marker, a payload, some combination thereof, etc.). The second authentication data may be compared to the authentication data (e.g., included in the first message) to verify the authenticity of the first computer system (e.g.,  110 ), verify the integrity of the first message, detect and/or act on a replay attack, some combination thereof, etc. 
     In one embodiment, the second authentication data may be generated in step  1320  using an authentication mechanism such as HMAC, OAuth, OAuth 2.0, OpenID, etc. The second authentication data may be generated in step  1320  using a key in one embodiment. For example, where the authentication mechanism used to generate the second authentication data in step  1320  is HMAC, the second authentication data may be generated by performing a hash function (e.g., MD5, SHA-1, SHA256, SHA512, etc.) on at least a portion of the first message (e.g., a header, a token, at least one option, a payload marker, a payload, some combination thereof, etc.) using a key. And in one embodiment, the first message may be free of the key used to generate the second authentication data in step  1320 . 
     A key associated with the first computer system (e.g.,  110 ) may be used to generate the second authentication data in step  1320  in one embodiment. For example, the key may be a secret key or private key that is unique to the first computer system (e.g.,  110 ). The key may be stored locally at the third computer system (e.g.,  1430 ) in one embodiment. For example, the key may be stored locally in a security component (e.g.,  1432  of computer system  1430 ), in a memory (e.g., of computer system  1430 ), in a database (e.g., of computer system  1430 ), etc. Alternatively, the key may be stored remotely (e.g., at another system or device) and accessed by the third computer system (e.g.,  1430 ) in a secure manner in one embodiment. Accordingly, a key associated with the first computer system (e.g.,  110 ) may be securely accessed and used by the third computer system (e.g.,  1430 ) to generate the second authentication data in step  1320  in one embodiment. 
     Step  1320  may involve generating the second message (e.g., including a first data portion associated with a security token and a second data portion including an instance of a session key) at the third computer system (e.g.,  1430 ) in one embodiment. In one embodiment, the second message may be generated using a message generation component (e.g.,  1434 ) alone or in combination with at least one other component (e.g., security component  1432 , etc.). 
     The second message may be generated based on the results of the first processing in one embodiment. For example, if the first computer system (e.g.,  110 ) is authorized to communicate with and/or connect to the second system (e.g.,  120 ) and/or if the first message is valid, then the second message may be generated in step  1320 . 
     In one embodiment, the first data portion of the second message may include a first instance of a session key, and the second data portion of the second message may include a second instance of the session key. The session key and/or a plurality of instances thereof may be generated in step  1320  at the third computer system (e.g.,  1430 ) in one embodiment. In one embodiment, the session key and/or a plurality of instances thereof may be generated using a security component (e.g.,  1432 ). In one embodiment, the session key may be generated in step  1320  based on a random number, pseudorandom number, other data, some combination thereof, etc. A third instance of the session key may be stored at the third computer system (e.g.,  1430 ) in one embodiment. 
       FIG. 19  shows data portion  1900  associated with a security token in accordance with one embodiment. In one embodiment, data portion  1900  may be, or be used to implement, the first data portion included in the second message generated in step  1320 . 
     As shown in  FIG. 19 , data portion  1900  may include portion  1910  associated with a unique identifier of a caller system (e.g., the first computer system or computer system  110 ), portion  1920  associated with a unique identifier of a target system (e.g., the second computer system or computer system  120 ), portion  1930  associated with expiration data, portion  1940  associated with an instance of a session key, some combination thereof, etc. 
     In one embodiment, the unique identifier of the first computer system (e.g.,  110 ) may be included in or otherwise associated with portion  1910 , and the unique identifier of the second computer system (e.g.,  120 ) may be included in or otherwise associated with portion  1920 . In one embodiment, expiration data associated with portion  1930  may include a timestamp (e.g., associated with creation of the security token and/or session key), a duration or lifetime (e.g., of the security token and/or session key), other data, some combination thereof, etc. Where the expiration data includes a timestamp, the timestamp may be a UTC timestamp, unix timestamp, epoch timestamp, another type of timestamp, etc. Where the expiration data includes a duration or lifetime, the duration or lifetime may include a timeout. 
     The duration or lifetime may be set or determined by the second computer system (e.g.,  120 ) or another computer system associated therewith in one embodiment. For example, the second computer system (e.g.,  120 ) or another computer system associated therewith may communicate information about the duration or lifetime to the third computer system (e.g.,  1430 ), where the third computer system may access and/or store the information about the duration or lifetime (e.g., for generation of and/or inclusion in portion  1930 ). 
     In one embodiment, portion  1940  may be associated with an instance (e.g., a first instance) of the session key generated by the third computer system (e.g.,  1430 ) which may correspond to at least one other instance of the session key (e.g., a second instance included in the second data portion of the second message, a third instance stored at the third computer system, etc.). And in one embodiment, the expiration data (e.g., associated with portion  1930 ) may correspond to the instance of the session key associated with portion  1940  (and/or at least one other instance of the session key). 
     Data portion  1900  may form the security token in one embodiment. For example, portion  1910 , portion  1920 , portion  1930 , and portion  1940  may form the security token. Alternatively, one or more portions of data portion  1900  may form the security token in one embodiment. For example, portion  1910 , portion  1920 , and portion  1930  may form the security token. As another example, portion  1920 , portion  1930 , and portion  1940  may form the security token. As yet another example, another combination of portions, or any one portion alone, may form the security token. In this manner, one or more portions of data portion  1900  may be separate from the security token in one embodiment. 
     Although  FIG. 19  shows data portion  1900  as including a particular amount of data, it should be appreciated that a different amount of data may be included in data portion  1900  in other embodiments. Additionally, although  FIG. 19  shows data portion  1900  as including a particular arrangement and type of data, it should be appreciated that a different arrangement and/or type of data may be included in data portion  1900  in other embodiments. 
     Turning back to  FIG. 13A , step  1320  may involve encrypting data to generate the first data portion associated with the security token in one embodiment. The data may include a first instance of the session key and/or other data (e.g., associated with the security token such as a first unique identifier associated with the caller system, a second unique identifier associated with the target system, expiration data associated with the security token and/or session key, etc.). And in one embodiment, the first data portion may be generated by encrypting the data in step  1320  using AES, Blowfish, RC4, the Extended Tiny Encryption Algorithm (XTEA) scheme, another symmetric-key algorithm, etc. 
     In one embodiment, a key associated with the second computer system (e.g.,  120 ) may be used to encrypt the data to generate the first data portion in step  1320 . For example, the key may be a secret key or private key that is unique to the second computer system (e.g.,  120 ). The key may be stored locally at the third computer system (e.g.,  1430 ) in one embodiment. For example, the key may be stored locally in a security component (e.g.,  1432  of computer system  1430 ), in a memory (e.g., of computer system  1430 ), in a database (e.g., of computer system  1430 ), etc. Alternatively, the key may be stored remotely (e.g., at another system or device) and accessed by the third computer system (e.g.,  1430 ) in a secure manner in one embodiment. Accordingly, a key associated with the second computer system (e.g.,  120 ) may be securely accessed and used by the third computer system (e.g.,  1430 ) to encrypt data to generate the first data portion in step  1320  in one embodiment. 
     In one embodiment, step  1320  may involve encrypting data to generate the second data portion in one embodiment. The data may include a second instance of the session key. And in one embodiment, the second data portion may be generated by encrypting the data in step  1320  using AES, Blowfish, RC4, the Extended Tiny Encryption Algorithm (XTEA) scheme, another symmetric-key algorithm, etc. 
     In one embodiment, a key associated with the first computer system (e.g.,  110 ) may be used to encrypt the data to generate the second data portion in step  1320 . For example, the key may be a secret key or private key that is unique to the first computer system (e.g.,  110 ). The key may be stored locally at the third computer system (e.g.,  1430 ) in one embodiment. For example, the key may be stored locally in a security component (e.g.,  1432  of computer system  1430 ), in a memory (e.g., of computer system  1430 ), in a database (e.g., of computer system  1430 ), etc. Alternatively, the key may be stored remotely (e.g., at another system or device) and accessed by the third computer system (e.g.,  1430 ) in a secure manner in one embodiment. Accordingly, a key associated with the first computer system (e.g.,  110 ) may be securely accessed and used by the third computer system (e.g.,  1430 ) to encrypt data to generate the second data portion in step  1320  in one embodiment. 
     The first data portion and/or the second data portion may be included in or as the payload of the second message in step  1320  in one embodiment. And in one embodiment, the first data portion and/or the second data portion may be included in or as another portion of the second message in step  1320 . 
     Step  1320  may involve generating authentication data to be included in the second message in one embodiment. The authentication data may be generated in step  1320  at the third computer system (e.g.,  1430 ) in one embodiment. And in one embodiment, the authentication data may be generated in step  1320  using a security component (e.g.,  1432  of computer system  1430 ). 
     In one embodiment, the authentication data may be generated in step  1320  using an authentication mechanism such as HMAC, OAuth, OAuth 2.0, OpenID, etc. The authentication data may be generated in step  1320  using a key in one embodiment. For example, where the authentication mechanism used to generate the authentication data in step  1320  is HMAC, the authentication data may be generated by performing a hash function (e.g., MD5, SHA-1, SHA256, SHA512, etc.) on message data (e.g., a header, a token, at least one option, a payload marker, a payload, the first data portion associated with a security token, the second data portion including an instance of a session key, some combination thereof, etc.) using a key. And in one embodiment, the message data may be free of the key used to generate the authentication data in step  1320 . 
     A key associated with the first computer system (e.g.,  110 ) may be used to generate the authentication data in step  1320  in one embodiment. For example, the key may be a secret key or private key that is unique to the first computer system (e.g.,  110 ). The key may be stored locally at the third computer system (e.g.,  1430 ) in one embodiment. For example, the key may be stored locally in a security component (e.g.,  1432  of computer system  1430 ), in a memory (e.g., of computer system  1430 ), in a database (e.g., of computer system  1430 ), etc. Alternatively, the key may be stored remotely (e.g., at another system or device) and accessed by the third computer system (e.g.,  1430 ) in a secure manner in one embodiment. Accordingly, a key associated with the first computer system (e.g.,  110 ) may be securely accessed and used by the third computer system (e.g.,  1430 ) to generate the authentication data in step  1320  in one embodiment. 
     In one embodiment, the authentication data may be included in or as the payload of the second message in step  1320 . And in one embodiment, the authentication data may be included in or as another portion of the second message in step  1320 . 
     The second message may be a CoAP message (e.g.,  1700 B of  FIG. 17B ) in one embodiment. As shown in  FIG. 17B , CoAP message  1700 B may include data associated with a header, where the data associated with the header includes data associated with a version (e.g., “ 1 ”), a message type (e.g., “ACK” or acknowledgement), a token length (e.g., “1” associated with a length of 1 byte), a code (e.g., a response code of “Content”), and a message identifier (e.g., “0x7d34”). Data associated with a token (e.g., “0x72”) may also be included in CoAP message  1700 B. 
     CoAP message  1700 B may include data associated with at least one option. For example, CoAP message  1700 B may include data associated with a max-age value (e.g., an option value of “0”). In this case, a max-age value of “0” may be used to indicate that CoAP message  1700 B is not to be cached by an intermediary system or device (e.g., situated between the sender of the CoAP message  1700 B and the ultimate recipient of the CoAP message  1700 B) such as a proxy server or other type of computer system or device. 
     As another example, CoAP message  1700 B may include data associated with a query (e.g., including one or more parameters). An option value of “uid=cs1430” (e.g., associated with a first parameter) may be associated with a unique identifier (e.g., “cs1430”) of a sender of CoAP message  1700 B (e.g., computer system  1430 ). An option value of “hs256=1” (e.g., associated with a second parameter) may be associated with an authentication mechanism (e.g., HMAC utilizing a hash function of SHA256) used to generate the authentication data (e.g., “Authentication Data B”) included in CoAP message  1700 B. An option value of “nonce=1” (e.g., associated with a third parameter) may be associated with a nonce (e.g., with a value of “1”) included in CoAP message  1700 B. 
     CoAP message  1700 B may include data associated with at least one option length. For example, CoAP message  1700 B may include data associated with a first option length (e.g., 1 byte) corresponding to data associated with a first option value (e.g., “0”), a second option length (e.g., 10 bytes) corresponding to data associated with a second option value (e.g., “uid=cs1430”), a third option length (e.g., 7 bytes) corresponding to data associated with a third option value (e.g., “hs256=1”), etc. 
     As shown in  FIG. 17B , CoAP message  1700 B may include data associated with at least one option identifier. The at least one option identifier may include data associated with an option number and/or an option delta in one embodiment. For example, CoAP message  1700 B may include data associated with a first numerical value (e.g., “14”) as a first option identifier corresponding to a first option (e.g., associated with a max-age value), where the first numerical value (e.g., “14”) may be the delta or difference between the current option number (e.g., “14”) and the option number of the preceding option (e.g., “0” in this case since this is the first option). As such, the first numerical value of “14” may correspond to an option number of “14.” 
     As another example, CoAP message  1700 B may include data associated with a second numerical value (e.g., “1”) as a second option identifier corresponding to a second option (e.g., associated with a query), where the second numerical value (e.g., “1”) may be the delta or difference between the current option number (e.g., “15”) and the option number of the preceding option (e.g., “14”). As such, the second numerical value of “1” may correspond to an option number of “15.” 
     As a further example, CoAP message  1700 B may include data associated with a third numerical value (e.g., “0”) as a third option identifier corresponding to a third option (e.g., associated with a query), where the third numerical value (e.g., “0”) may be the delta or difference between the current option number (e.g., “15”) and the option number of the preceding option (e.g., “15”). As such, the third numerical value of “0” may correspond to an option number of “15.” 
     As shown in  FIG. 17B , CoAP message  1700 B may include data associated with a payload marker (e.g., “0xFF”). CoAP message  1700 B may include data associated with a payload, where the data associated with a payload may include authentication data (e.g., “Authentication Data B”) and/or other data. In one embodiment, the other data may be or include a first data portion associated with a security token (e.g., “First Data Portion Associated With Security Token”), a second data portion including an instance of a session key (e.g., “Second Data Portion Including Instance Of Session Key”), other data, some combination thereof, etc. 
     CoAP message  1700 A and CoAP message  1700 B may share a common message identifier (e.g., “0x7d34”) in one embodiment. CoAP message  1700 A and CoAP message  1700 B may share a common token (e.g., “0x72”) in one embodiment. 
     In one embodiment, a message type associated with CoAP message  1700 B (e.g., “ACK” or acknowledgement) may correspond to and/or be determined by a message type associated with CoAP message  1700 A (e.g., “CON” or confirmable). And in one embodiment, a response code associated with CoAP message  1700 B (e.g., “Content”) may correspond to and/or be determined by a method code associated with CoAP message  1700 A (e.g., “GET”). In this case, CoAP message  1700 B may include data (e.g., a first data portion associated with a security token, a second data portion including an instance of a session key, etc.) associated with the request of CoAP message  1700 A (e.g., a request for data associated with a security token, data associated with a session key and/or at least one instance thereof, etc.). 
     Although  FIG. 17B  shows CoAP message  1700 B with a specific number and type of portions, it should be appreciated that CoAP message  1700 B may include a different number and/or type of portions in other embodiments. For example, CoAP message  1700 B may include fewer portions or at least one additional portion. As another example, a plurality of portions of CoAP message  1700 B may be combined into a smaller number of portions. Although  FIG. 17B  shows CoAP message  1700 B with a specific organization of portions, it should be appreciated that CoAP message  1700 B may include a different organization of portions in other embodiments. 
     In one embodiment, data associated with at least one option may be excluded from CoAP message  1700 B. For example, data (e.g., associated with a host, a port, a path, a max-age value, or some combination thereof) used by intermediary systems or devices (e.g., situated between the sender of CoAP message  1700 B and the ultimate recipient of CoAP message  1700 B) such as a proxy server or other type of computer system or device may be excluded in one or more embodiments where intermediary systems or devices do not exist or are unlikely to exist. 
     Turning back to  FIG. 13A , step  1320  may involve formatting at least one data portion (e.g., a first data portion associated with a security token, a second data portion including an instance of a session key, etc.) of the second message in accordance with JSON (JavaScript Object Notation) in one embodiment. Alternatively, at least one data portion (e.g., a first data portion associated with a security token, a second data portion including an instance of a session key, etc.) of the second message may be formatted in step  1320  in accordance with another format (e.g., UTF-8 plain text, link format, XML, octet-stream, etc.). Where the second message is a CoAP message (e.g.,  1700 B), the second message may include data associated with a content format (e.g., a “Content-Format” option with an option value corresponding to a format of a payload of CoAP message  1700 B, a format of a first data portion associated with a security token, a format of a second data portion including an instance of a session key, etc.) in one embodiment. 
     Step  1320  may be performed in accordance with one or more steps of process  2000  of  FIGS. 20A and 20B  in one embodiment.  FIGS. 20A and 20B  show a flowchart of process  2000  for performing processing associated with a message in accordance with one embodiment. One or more steps of process  2000  may be performed at or by a third computer system (e.g.,  1430 ) in one embodiment. 
     As shown in  FIG. 20A , step  2005  involves receiving a message. In one embodiment, the message received in step  2005  may be the message generated in step  1310 , generated in step  1830 , communicated in step  1315 , some combination thereof, etc. Step  2005  may involve receiving the message at the third computer system (e.g.,  1430 ) from another computer system (e.g.,  110 , another system or device, etc.) in one embodiment. 
     In one embodiment, the message may be received in step  2005  over a connection (e.g.,  1415 ). The message may be received in step  2005  as a bit stream or a byte stream in one embodiment. And in one embodiment, step  2005  may involve receiving the message using a communication interface (e.g.,  1438 ). 
     As shown in  FIG. 20A , step  2010  involves processing the message (e.g., received in step  2005 ). Authentication data may be accessed from the message in step  2010  in one embodiment. A unique identifier associated with the caller system (e.g., the first computer system or computer system  110 ) may be accessed from the message in step  2010  in one embodiment. In one embodiment, step  2010  may involve processing the message using a security component (e.g.,  1432  of computer system  1430 ). And in one embodiment, where the message is a CoAP message, step  2010  may be performed in accordance with step  650  and/or one or more steps of process  900  of  FIG. 9 . 
     Step  2015  involves performing message validation (e.g., with respect to the message received in step  2005 ). The message validation may be used to verify the authenticity of the sender of the message and/or the integrity of the message. Where the message includes a nonce, the message validation may be used to detect a replay attack. 
     In one embodiment, message validation may be performed in step  2015  based on authentication data (e.g., accessed from the message in step  2010 ). And in one embodiment, message validation may be performed in step  2015  using at least one message invalidity condition. 
     Where message validation is performed based on authentication data, message validation may be performed in step  2015  by comparing second authentication data to the authentication data in one embodiment. For example, the third computer system (e.g.,  1430 ) may generate second authentication data based on at least a portion of the message (e.g., a header, a token, at least one option, a payload marker, a payload, some combination thereof, etc.). The second authentication data may be compared to the authentication data (e.g., included in the message and/or accessed in step  2010 ) to verify the authenticity of the sender of the message (e.g., the first computer system or computer system  110 ), verify the integrity of the message, detect and/or act on a replay attack, some combination thereof, etc. 
     In one embodiment, the second authentication data may be generated in step  2015  using an authentication mechanism such as HMAC, OAuth, OAuth 2.0, OpenID, etc. The second authentication data may be generated in step  2015  using a key in one embodiment. For example, where the authentication mechanism used to generate the second authentication data in step  2015  is HMAC, the second authentication data may be generated by performing a hash function (e.g., MD5, SHA-1, SHA256, SHA512, etc.) on at least a portion of the message (e.g., a header, a token, at least one option, a payload marker, a payload, some combination thereof, etc.) using a key. And in one embodiment, the message may be free of the key used to generate the second authentication data in step  2015 . 
     A key associated with the caller system (e.g., the first computer system or computer system  110 ) may be used to generate the second authentication data in step  2015  in one embodiment. For example, the key may be a secret key or private key that is unique to the caller system (e.g., the first computer system or computer system  110 ). The key may be stored locally at the third computer system (e.g.,  1430 ) in one embodiment. For example, the key may be stored locally in a security component (e.g.,  1432  of computer system  1430 ), in a memory (e.g., of computer system  1430 ), in a database (e.g., of computer system  1430 ), etc. Alternatively, the key may be stored remotely (e.g., at another system or device) and accessed by the third computer system (e.g.,  1430 ) in a secure manner in one embodiment. Accordingly, a key associated with the caller system (e.g., the first computer system or computer system  110 ) may be securely accessed and used by the third computer system (e.g.,  1430 ) to generate the second authentication data in step  2015  in one embodiment. 
     Where message validation is performed using at least one message invalidity condition, the message may be determined to be invalid in step  2015  if any of the at least one message invalidity condition is triggered in one embodiment. For example, the message may be determined to be invalid in step  2015  responsive to a failure to access a unique identifier associated with the sender of the message (e.g., the first computer system or computer system  110 ). As another example, the message may be determined to be invalid in step  2015  responsive to a failure to access a nonce from the message. As a further example, the message may be determined to be invalid in step  2015  responsive to determining that a nonce accessed from the message is not different from another nonce accessed from a previous message. As yet another example, the message may be determined to be invalid in step  2015  responsive to determining that a payload of the message is not at least a predetermined size. And as another example, the message may be determined to be invalid in step  2015  responsive to a failure to access a key (e.g., associated with the first computer system or computer system  110 ) used to generate the second authentication data or otherwise perform the message validation. 
     The message validation may be performed in step  2015  using a security component (e.g.,  1432  of computer system  1430 ) in one embodiment. And in one embodiment, where the message is a CoAP message, step  2015  may be performed in accordance with step  660 , one or more steps of process  1000  of  FIG. 10 , one or more steps of process  1100  of  FIG. 11 , some combination thereof, etc. 
     As shown in  FIG. 20A , step  2020  involves determining whether the message (e.g., received in step  2005 ) is valid (e.g., based on the results of the message validation performed in step  2015 ). Step  2020  may be performed using a security component (e.g.,  1432  of computer system  1430 ) in one embodiment. If it is determined in step  2020  that the message (e.g., received in step  2005 ) is valid, then step  2025  may be performed. 
     Step  2025  involves accessing, from the message, a unique identifier associated with a target system (e.g., the second computer system or computer system  120 ). Step  2025  may be performed using a security component (e.g.,  1432  of computer system  1430 ) in one embodiment. 
     As shown in  FIG. 20A , step  2030  involves determining whether the caller system is authorized to communicate with and/or connect to the target system. The caller system may be the sender of the message (e.g., the first computer system or computer system  110 ), and the target system may be the system or device associated with the unique identifier accessed in step  2025  (e.g., the second computer system or computer system  120 ). In one embodiment, step  2030  may be performed using a security component (e.g.,  1432  of computer system  1430 ). 
     Determination of whether the caller system is authorized to communicate with and/or connect to the target system may be performed in step  2030  based on permissions configuration data (e.g.,  1600  of  FIG. 16 , generated and/or updated in step  1305 , generated and/or updated in step  1540  of process  1500 , etc.) in one embodiment. For example, permissions configuration data may be accessed to determine whether the first computer system (e.g.,  110 ) is authorized to communicate with and/or connect to the second computer system (e.g.,  120 ). 
     In one embodiment, the permissions configuration data may be accessed in step  2030  using a unique identifier associated with the target system (e.g., accessed in step  2025 ), using a unique identifier associated with the caller system (e.g., accessed from the message in step  2010 , in step  2015  as part of message validation, etc.), some combination thereof, etc. And in one embodiment, the permissions configuration data may be stored at the third computer system (e.g.,  1430 ), stored remotely and accessible to the third computer system (e.g.,  1430 ), etc. 
     If it is determined in step  2030  that the caller system is authorized to communicate with the target system, then step  2035  may be performed. As shown in  FIG. 20B , step  2035  involves generating a session key. In one embodiment, step  2035  may involve generating a plurality of instances of the session key. 
     The session key and/or a plurality of instances thereof may be generated in step  2035  using a security component (e.g.,  1432 ) in one embodiment. In one embodiment, the session key and/or a plurality of instances thereof may be generated in step  2035  based on a random number, pseudorandom number, other data, some combination thereof, etc. And in one embodiment, at least one instance of the session key may be stored at the third computer system (e.g.,  1430 ). 
     In one embodiment, the session key and/or a plurality of instances thereof may be stored in step  2035 . For example, data associated with the session key and/or a plurality of instances thereof (e.g., data  2100  of  FIG. 21 ) may be stored at the third computer system (e.g.,  1430 ). 
       FIG. 21  shows data  2100  associated with at least one session key in accordance with one embodiment. As shown in  FIG. 21 , each session key in column  2130  may correspond to respective computer systems associated with respective unique identifiers in columns  2110  and  2120 . For example, a first session key (e.g., “Session Key  1 ”) may correspond to a first computer system (e.g., associated with the unique identifier of “cs110” in column  2120 ) and a second computer system (e.g., associated with the unique identifier of “cs120” in column  2110 ). As another example, a second session key (e.g., “Session Key 2”) may correspond to another computer system (e.g., associated with the unique identifier of “cs130” in column  2120 ) and the second computer system (e.g., associated with the unique identifier of “cs120” in column  2110 ). 
     Each session key in column  2130  may correspond to computer systems (e.g., associated with unique identifiers in columns  2110  and  2120 ) that are authorized to communicate with and/or connect to one another (e.g., responsive to configuration of permissions in step  1305  of process  1300  and/or one or more steps of process  1500  of  FIG. 15 ) in one embodiment. For example, a first session key (e.g., “Session Key  1 ”) may correspond to a first computer system (e.g., associated with the unique identifier of “cs110” in column  2120 ) and a second computer system (e.g., associated with the unique identifier of “cs120” in column  2110 ) that are authorized to communicate with and/or connect to one another (e.g., responsive to configuration of permissions in step  1305  of process  1300  and/or one or more steps of process  1500  of  FIG. 15 ). As another example, a second session key (e.g., “Session Key  2 ”) may correspond to another computer system (e.g., associated with the unique identifier of “cs130” in column  2120 ) and the second computer system (e.g., associated with the unique identifier of “cs120” in column  2110 ) that are authorized to communicate with and/or connect to one another (e.g., responsive to configuration of permissions in step  1305  of process  1300  and/or one or more steps of process  1500  of  FIG. 15 ). 
     In one embodiment, the unique identifiers in column  2110  may be associated with target systems, and the unique identifiers in column  2120  may be associated with caller systems. In this manner, data  2100  may include a correlation or mapping of at least one caller system (e.g., in column  2120 ) that is authorized to communicate with and/or connect to at least one target system (e.g., in column  2110 ). 
     At least a portion of data  2100  may correlate to and/or be the same as permissions configuration data (e.g.,  1600  of  FIG. 16 ) in one embodiment. For example, column  2110  may correlate to and/or be the same as column  1610  of permissions configuration data  1600 . As another example, column  2120  may correlate to and/or be the same as column  1620  of permissions configuration data  1600 . As such, in one embodiment, data of column  2130  may be added to permissions configuration data (e.g.,  1600 ) responsive to generation of and/or updating of a session key (or at least one instance thereof). 
     In one embodiment, data  2100  may be stored locally at the third computer system (e.g.,  1430 ). For example, data  2100  may be stored locally in a security component (e.g.,  1432  of computer system  1430 ), in a memory (e.g., of computer system  1430 ), in a database (e.g., of computer system  1430 ), etc. Alternatively, data  2100  may be stored remotely (e.g., at another system or device) and accessed by the third computer system (e.g.,  1430 ) in a secure manner in one embodiment. Accordingly, a session key and/or at least one instance thereof may be securely accessed (e.g., from or using data  2100 ) and included in at least one portion (e.g., a first data portion associated with a security token, a second data portion including an instance of a session key, etc.) of a message (e.g., the second message generated in step  2060  of process  2000 ). 
     Data  2100  may be changed or updated in one embodiment. For example, data  2100  may be changed or updated based on expiration data (e.g., associated with portion  1930  of data portion  1900 ) such as a timestamp (e.g., associated with creation of the security token and/or session key), a duration or lifetime (e.g., of the security token and/or session key), etc. In this case, a portion of data  2100  associated with at least one session key may be removed from data  2100  and/or updated (e.g., with new data corresponding to at least one new session key) responsive to expiration of the security token and/or the at least one session key. 
     Although  FIG. 21  shows data  2100  as including a particular amount of data, it should be appreciated that a different amount of data may be included in data  2100  in other embodiments. Additionally, although  FIG. 21  shows data  2100  as including a particular arrangement and type of data, it should be appreciated that a different arrangement and/or type of data may be included in data  2100  in other embodiments. 
     Turning back to  FIG. 20B , step  2040  involves generating a first data portion, including a first instance of the session key, associated with a security token. In one embodiment, step  2040  may be performed using a security component (e.g.,  1432 ) alone or in combination with at least one other component (e.g., message generation component  1434 , etc.). 
     In one embodiment, the first data portion generated in step  2040  may include one or more portions of data portion  1900 . For example, the first data portion may include a plurality of portions of data portion  1900  (e.g., portion  1940  associated with an instance of the session key and at least one other portion such as portion  1910  associated with a unique identifier of a caller system, portion  1920  associated with a unique identifier of a target system, portion  1930  associated with expiration data, some combination thereof, etc.). As another example, the first data portion may include only one portion of data portion  1900  (e.g., portion  1940  associated with an instance of the session key). 
     The first data portion may include the first instance of the session key as part of the security token in one embodiment. Alternatively, the first data portion may include the first instance of the session key separate from the security token. 
     In one embodiment, a key associated with the target system (e.g., the second computer system or computer system  120 ) may be used to encrypt the data to generate the first data portion in step  2040 . For example, the key may be a secret key or private key that is unique to the target system (e.g., the second computer system or computer system  120 ). In one embodiment, the first data portion may be generated by encrypting the data in step  2040  using AES, Blowfish, RC4, the Extended Tiny Encryption Algorithm (XTEA) scheme, another symmetric-key algorithm, etc. 
     Where a key is used to encrypt the data to generate the first data portion, the key may be stored locally at the third computer system (e.g.,  1430 ) in one embodiment. For example, the key may be stored locally in a security component (e.g.,  1432  of computer system  1430 ), in a memory (e.g., of computer system  1430 ), in a database (e.g., of computer system  1430 ), etc. Alternatively, the key may be stored remotely (e.g., at another system or device) and accessed by the third computer system (e.g.,  1430 ) in a secure manner in one embodiment. Accordingly, a key associated with the target system (e.g., the second computer system or computer system  120 ) may be securely accessed and used by the third computer system (e.g.,  1430 ) to encrypt data to generate the first data portion in step  2040  in one embodiment. 
     As shown in  FIG. 20B , step  2045  involves generating a second data portion including a second instance of the session key. In one embodiment, step  2045  may be performed using a security component (e.g.,  1432 ) alone or in combination with at least one other component (e.g., message generation component  1434 , etc.). 
     Step  2045  may involve encrypting data to generate the second data portion in one embodiment. The data may include a second instance of the session key. 
     In one embodiment, a key associated with the caller system (e.g., the first computer system or computer system  110 ) may be used to encrypt the data to generate the second data portion in step  2045 . For example, the key may be a secret key or private key that is unique to the caller system (e.g., the first computer system or computer system  110 ). In one embodiment, the second data portion may be generated by encrypting the data in step  2045  using AES, Blowfish, RC4, the Extended Tiny Encryption Algorithm (XTEA) scheme, another symmetric-key algorithm, etc. 
     Where a key is used to encrypt the data to generate the second data portion, the key may be stored locally at the third computer system (e.g.,  1430 ) in one embodiment. For example, the key may be stored locally in a security component (e.g.,  1432  of computer system  1430 ), in a memory (e.g., of computer system  1430 ), in a database (e.g., of computer system  1430 ), etc. Alternatively, the key may be stored remotely (e.g., at another system or device) and accessed by the third computer system (e.g.,  1430 ) in a secure manner in one embodiment. Accordingly, a key associated with the caller system (e.g., the first computer system or computer system  110 ) may be securely accessed and used by the third computer system (e.g.,  1430 ) to encrypt data to generate the second data portion in step  2045  in one embodiment. 
     As shown in  FIG. 20B , step  2050  involves accessing message data including the first data portion (e.g., generated in step  2040 ) and the second data portion (e.g., generated in step  2045 ). In one embodiment, step  2050  may be performed using a message generation component (e.g.,  1434 ). 
     In one embodiment, the message data accessed in step  2050  may include data other than authentication data. For example, the message data may include data associated with a header (e.g., included in portion  210  of CoAP message  200 ), data associated with a token (e.g., included in portion  220  of CoAP message  200 ), data associated with at least one option (e.g., included in portion  230  of CoAP message  200 ), data associated with a payload marker (e.g., included in portion  240  of CoAP message  200 ), data associated with at least a portion of a payload (e.g., included in portion  250  of CoAP message  200 ), data other than the authentication data (e.g., “Authentication Data B” of CoAP message  1700 B), some combination thereof, etc. 
     As shown in  FIG. 20B , step  2055  involves generating authentication data. In one embodiment, step  2055  may be performed using a security component (e.g.,  1432  of computer system  1430 ). 
     In one embodiment, the authentication data may be generated in step  2055  using an authentication mechanism such as HMAC, OAuth, OAuth 2.0, OpenID, etc. The authentication data may be generated in step  2055  using a key in one embodiment. For example, where the authentication mechanism used to generate the authentication data in step  2055  is HMAC, the authentication data may be generated by performing a hash function (e.g., MD5, SHA-1, SHA256, SHA512, etc.) on message data (e.g., accessed in step  2050 ) using a key. And in one embodiment, the message data may be free of the key used to generate the authentication data in step  2055 . 
     A key associated with the caller system (e.g., the first computer system or computer system  110 ) may be used to generate the authentication data in step  2055  in one embodiment. For example, the key may be a secret key or private key that is unique to the caller system (e.g., the first computer system or computer system  110 ). The key may be stored locally at the third computer system (e.g.,  1430 ) in one embodiment. For example, the key may be stored locally in a security component (e.g.,  1432  of computer system  1430 ), in a memory (e.g., of computer system  1430 ), in a database (e.g., of computer system  1430 ), etc. Alternatively, the key may be stored remotely (e.g., at another system or device) and accessed by the third computer system (e.g.,  1430 ) in a secure manner in one embodiment. Accordingly, a key associated with the caller system (e.g., the first computer system or computer system  110 ) may be securely accessed and used by the third computer system (e.g.,  1430 ) to generate the authentication data in step  2055  in one embodiment. 
     As shown in  FIG. 20B , step  2060  involves generating a message including the message data (e.g., accessed in step  2050 ) and the authentication data (e.g., generated in step  2055 ). In one embodiment, step  2060  may be performed using a message generation component (e.g.,  1434  of computer system  1430 ). 
     In one embodiment, where the message generated in step  2060  is a CoAP message (e.g.,  1700 B), step  2060  may involve formatting the message data (e.g., accessed in step  2050 ) in accordance with CoAP (e.g., into one or more portions of CoAP message  200 ). The authentication data (e.g., generated in step  2055 ) may be included in or as the payload (e.g., associated with portion  250  of CoAP message  200 ) of the CoAP message in one embodiment. For example, as shown in  FIG. 17B , authentication data (e.g., “Authentication Data B”) may be included in or as the payload of CoAP message  1700 B. 
     The first data portion (e.g., generated in step  2040 ) and/or the second data portion (e.g., generated in step  2045 ) may be included in or as the payload of the message (e.g., generated in step  2060 ) in one embodiment. For example, as shown in  FIG. 17B , the first data portion (e.g., “First Data Portion Associated With Security Token”) and/or the second data portion (e.g., “Second Data Portion Including Instance Of Session Key”) may be included in or as the payload of CoAP message  1700 B in step  2060 . And in one embodiment, the first data portion and/or the second data portion may be included in or as another portion of the message in step  2060 . 
     Step  2060  may involve generating a bit stream or byte stream including the message data (e.g., accessed in step  2050 ) and the authentication data (e.g., generated in step  2055 ) in one embodiment. The bit stream or byte stream may be formatted in accordance with CoAP in one embodiment. 
     In one embodiment, step  2060  may involve formatting at least one data portion (e.g., a first data portion associated with a security token, a second data portion including an instance of a session key, etc.) of the message in accordance with JSON (JavaScript Object Notation). Alternatively, at least one data portion (e.g., a first data portion associated with a security token, a second data portion including an instance of a session key, etc.) of the message may be formatted in step  2060  in accordance with another format (e.g., UTF-8 plain text, link format, XML, octet-stream, etc.). Where the message generated in step  2060  is a CoAP message (e.g.,  1700 B), the message may include data associated with a content format (e.g., a “Content-Format” option with an option value corresponding to a format of a payload of CoAP message  1700 B, a format of a first data portion associated with a security token, a format of a second data portion including an instance of a session key, etc.) in one embodiment. 
     Turning back to  FIG. 20A , step  2065  involves performing at least one operation associated with the message. In one embodiment, the at least one operation may be performed in step  2065  if the message (e.g., received in step  2005 ) is determined to be invalid in step  2020 . And in one embodiment, the at least one operation may be performed in step  2065  if it is determined that the caller system (e.g., the first computer system or computer system  110 ) is not authorized to communicate with and/or connect to the target system (e.g., the second computer system or computer system  120 ) in step  2030 . And in one embodiment, step  2065  may involve performing at least one operation using an operation component (e.g.,  1436  of computer system  1430 ). 
     In one embodiment, step  2065  may involve acting responsive to a message validation failure such as a triggering of a message invalidity condition (e.g., corresponding to one or more steps of process  1100 , a failure to access a unique identifier associated with the sender of the message, a failure to access a nonce from the message, determining that a nonce accessed from the message is not different from another nonce accessed from a previous message, determining that a payload of the message is not at least a predetermined size, a failure to access a key used to generate the second authentication data or otherwise perform the message validation, some combination thereof, etc.), another message validation failure (e.g., determining that the second authentication data generated based on at least a portion of the message does not correlate to authentication data accessed from the message, another message validation failure, etc.), etc. And in one embodiment, step  2065  may involve acting on a suspected or detected replay attack. 
     The at least one operation performed in step  2065  may include ignoring the message (e.g., received in step  2005 ) in one embodiment. For example, another message may not be generated and/or communicated in reply to the message (e.g., received in step  2005 ) in step  2065 . As another example, no further processing related to the message (e.g., received in step  2005 ) may be performed in step  2065 . And in one embodiment, the at least one operation performed in step  2065  may include limiting access to the recipient (e.g., the third computer system or computer system  1430 ) of the sender (e.g., the first computer system or computer system  110 ). 
     Although  FIGS. 20A and 20B  depict process  2000  as including a specific number of steps, it should be appreciated that process  2000  may include a different number of steps in other embodiments. Although  FIGS. 20A and 20B  depict process  2000  as including a specific ordering of steps, it should be appreciated that process  2000  may include a different ordering of steps in other embodiments. For example, steps  2015  and  2020  may be performed after steps  2025  and  2030  in one embodiment. 
     Turning back to  FIG. 13A , step  1325  involves communicating the second message (e.g., generated in step  1320  and/or in accordance with one or more steps of process  2000  of  FIGS. 20A and 20B ) from the third computer system (e.g.,  1430 ) to the first computer system (e.g.,  110 ). In one embodiment, the second message may be communicated in step  1325  over a connection (e.g.,  1415  between computer system  1430  and computer system  110 ). The second message may be communicated in step  1325  as a bit stream or a byte stream in one embodiment. And in one embodiment, step  1325  may involve communicating the second message using at least one communication interface (e.g.,  1438  of computer system  1430 ,  118  of computer system  110 , etc.). 
     In one embodiment, step  1325  may involve communicating the second message using DTLS. For example, where the second message is a CoAP message (e.g.,  1700 B), step  1325  may involve communicating the second message over CoAP using DTLS. 
     As shown in  FIG. 13A , step  1330  involves performing second processing associated with the second message, and responsive thereto, accessing an instance of the session key from the second message. In one embodiment, step  1330  may involve performing the second processing associated with the second message at the first computer system (e.g.,  110 ). For example, responsive to receiving the second message (e.g., generated in step  1320  and communicated in step  1325 ), the first computer system (e.g.,  110 ) may perform the second processing. And in one embodiment, the second processing may be performed using a security component (e.g.,  112 ). 
     The second processing may involve performing message validation with respect to the second message in one embodiment. Message validation may be performed in step  1330  based on authentication data accessed from the second message in one embodiment. For example, the first computer system (e.g.,  110 ) may generate second authentication data based on at least a portion of the second message (e.g., a header, a token, at least one option, a payload marker, a payload, the first data portion associated with a security token, the second data portion including an instance of a session key, some combination thereof, etc.). The second authentication data may be compared to the authentication data (e.g., included in the second message) to verify the authenticity of the third computer system (e.g.,  1430 ), verify the integrity of the second message, detect and/or act on a replay attack, some combination thereof, etc. 
     In one embodiment, the second authentication data may be generated in step  1330  using an authentication mechanism such as HMAC, OAuth, OAuth 2.0, OpenID, etc. The second authentication data may be generated in step  1330  using a key in one embodiment. For example, where the authentication mechanism used to generate the second authentication data in step  1330  is HMAC, the second authentication data may be generated by performing a hash function (e.g., MD5, SHA-1, SHA256, SHA512, etc.) on at least a portion of the second message (e.g., a header, a token, at least one option, a payload marker, a payload, the first data portion associated with a security token, the second data portion including an instance of a session key, some combination thereof, etc.) using a key. And in one embodiment, the second message may be free of the key used to generate the second authentication data in step  1330 . 
     A key associated with the first computer system (e.g.,  110 ) may be used to generate the second authentication data in step  1330  in one embodiment. For example, the key may be a secret key or private key that is unique to the first computer system (e.g.,  110 ). The key may be stored locally at the first computer system (e.g.,  110 ) in one embodiment. For example, the key may be stored locally in a security component (e.g.,  112  of computer system  110 ), in a memory (e.g., of computer system  110 ), in a database (e.g., of computer system  110 ), etc. Alternatively, the key may be stored remotely (e.g., at another system or device) and accessed by the first computer system (e.g.,  110 ) in a secure manner in one embodiment. Accordingly, a key associated with the first computer system (e.g.,  110 ) may be securely accessed and used by the first computer system (e.g.,  110 ) to generate the second authentication data in step  1330  in one embodiment. 
     In one embodiment, the session key (or an instance thereof) may be accessed from the second message in step  1330  based on the results of the second processing. For example, where the second processing includes performing message validation, the session key (or an instance thereof) may be accessed in step  1330  if the second message is valid. In one embodiment, the session key (or an instance thereof) may be accessed in step  1330  from the second data portion (e.g., including an instance of the session key, generated in step  1320 , generated in step  2045 , some combination thereof, etc.) of the second message. 
     Accessing the instance of the session key in step  1330  may involve decrypting the second data portion (e.g., including an instance of the session key, generated in step  1320 , generated in step  2045 , some combination thereof, etc.) of the second message in one embodiment. The second data portion of the second message may be decrypted in step  1330  using AES, Blowfish, RC4, the Extended Tiny Encryption Algorithm (XTEA) scheme, another symmetric-key algorithm, etc. 
     In one embodiment, a key associated with the first computer system (e.g.,  110 ) may be used to decrypt the second data portion (e.g., including an instance of the session key, generated in step  1320 , generated in step  2045 , some combination thereof, etc.) of the second message in step  1330 . The key may be a secret key or private key that is unique to the first computer system (e.g.,  110 ) in one embodiment. The key may be stored locally at the first computer system (e.g.,  110 ) in one embodiment. For example, the key may be stored locally in a security component (e.g.,  112  of computer system  110 ), in a memory (e.g., of computer system  110 ), in a database (e.g., of computer system  110 ), etc. Alternatively, the key may be stored remotely (e.g., at another system or device) and accessed by the first computer system (e.g.,  110 ) in a secure manner in one embodiment. Accordingly, in one embodiment, a key associated with the first computer system (e.g.,  110 ) may be securely accessed and used by the first computer system (e.g.,  110 ) to decrypt the second data portion to access an instance of the session key in step  1330 . 
     The key used to decrypt (e.g., in step  1330 ) the second data portion of the second message at the first computer system (e.g.,  110 ) may be the same key used to encrypt (e.g., in step  1320 , in step  2045 , etc.) data to form the second data portion at the third computer system (e.g.,  1430 ) in one embodiment. For example, where a key associated with the first computer system (e.g., a secret key or private key that is unique to the first computer system) is used by the third computer system to encrypt the data to form the second data portion of the second message (e.g., in step  1320 , in step  2045 , etc.), the same key associated with the first computer system may be used by the first computer system to decrypt the second data portion (e.g., in step  1330 ). In this manner, a symmetric-key algorithm may be used to secure a session key (or at least one instance thereof) communicated using one or more messages. 
     In one embodiment, step  1330  may be performed in accordance with one or more steps of process  2200  of  FIG. 22 .  FIG. 22  shows a flowchart of process  2200  for performing processing associated with a message in accordance with one embodiment. One or more steps of process  2200  may be performed at or by a caller system (e.g., the first computer system or computer system  110 ) in one embodiment. 
     As shown in  FIG. 22 , step  2210  involves receiving a message. In one embodiment, the message received in step  2210  may be the message generated in step  1320 , generated in step  2060 , communicated in step  1325 , some combination thereof, etc. Step  2210  may involve receiving the message at the caller system (e.g., the first computer system or computer system  110 ) from another computer system (e.g.,  1430 , another system or device, etc.) in one embodiment. 
     In one embodiment, the message may be received in step  2210  over a connection (e.g.,  1415 ). The message may be received in step  2210  as a bit stream or a byte stream in one embodiment. And in one embodiment, step  2210  may involve receiving the message using a communication interface (e.g.,  118 ). 
     As shown in  FIG. 22 , step  2220  involves processing the message (e.g., received in step  2210 ). Authentication data may be accessed from the message in step  2220  in one embodiment. In one embodiment, step  2220  may involve processing the message using a security component (e.g.,  112  of computer system  110 ). And in one embodiment, where the message is a CoAP message, step  2220  may be performed in accordance with step  650  and/or one or more steps of process  900  of  FIG. 9 . 
     Step  2230  involves performing message validation (e.g., with respect to the message received in step  2210 ). The message validation may be used to verify the authenticity of the sender of the message and/or the integrity of the message. Where the message includes a nonce, the message validation may be used to detect a replay attack. 
     In one embodiment, message validation may be performed in step  2230  based on authentication data (e.g., accessed from the message in step  2220 ). And in one embodiment, message validation may be performed in step  2230  using at least one message invalidity condition. 
     Where message validation is performed based on authentication data, message validation may be performed in step  2230  by comparing second authentication data to the authentication data in one embodiment. For example, the caller system (e.g., the first computer system or computer system  110 ) may generate second authentication data based on at least a portion of the message (e.g., a header, a token, at least one option, a payload marker, a payload, a first data portion associated with a security token, a second data portion including an instance of a session key, some combination thereof, etc.). The second authentication data may be compared to the authentication data (e.g., included in the message and/or accessed in step  2220 ) to verify the authenticity of the sender of the message (e.g., the third computer system or computer system  1430 ), verify the integrity of the message, detect and/or act on a replay attack, some combination thereof, etc. 
     In one embodiment, the second authentication data may be generated in step  2230  using an authentication mechanism such as HMAC, OAuth, OAuth 2.0, OpenID, etc. The second authentication data may be generated in step  2230  using a key in one embodiment. For example, where the authentication mechanism used to generate the second authentication data in step  2230  is HMAC, the second authentication data may be generated by performing a hash function (e.g., MD5, SHA-1, SHA256, SHA512, etc.) on at least a portion of the message (e.g., a header, a token, at least one option, a payload marker, a payload, a first data portion associated with a security token, a second data portion including an instance of a session key, some combination thereof, etc.) using a key. And in one embodiment, the message may be free of the key used to generate the second authentication data in step  2230 . 
     A key associated with the caller system (e.g., the first computer system or computer system  110 ) may be used to generate the second authentication data in step  2230  in one embodiment. For example, the key may be a secret key or private key that is unique to the caller system (e.g., the first computer system or computer system  110 ). The key may be stored locally at the first computer system (e.g.,  110 ) in one embodiment. For example, the key may be stored locally in a security component (e.g.,  112  of computer system  110 ), in a memory (e.g., of computer system  110 ), in a database (e.g., of computer system  110 ), etc. Alternatively, the key may be stored remotely (e.g., at another system or device) and accessed by the first computer system (e.g.,  110 ) in a secure manner in one embodiment. Accordingly, a key associated with the caller system (e.g., the first computer system or computer system  110 ) may be securely accessed and used by the caller system to generate the second authentication data in step  2230  in one embodiment. 
     Where message validation is performed using at least one message invalidity condition, the message may be determined to be invalid in step  2230  if any of the at least one message invalidity condition is triggered in one embodiment. For example, the message may be determined to be invalid in step  2230  responsive to a failure to access a unique identifier associated with the sender of the message (e.g., the third computer system or computer system  1430 ). As another example, the message may be determined to be invalid in step  2230  responsive to a failure to access a nonce from the message. As a further example, the message may be determined to be invalid in step  2230  responsive to determining that a nonce accessed from the message is not different from another nonce accessed from a previous message. As yet another example, the message may be determined to be invalid in step  2230  responsive to determining that a payload of the message is not at least a predetermined size. And as another example, the message may be determined to be invalid in step  2230  responsive to a failure to access a key (e.g., associated with the caller system) used to generate the second authentication data or otherwise perform the message validation. 
     The message validation may be performed in step  2230  using a security component (e.g.,  112  of computer system  110 ) in one embodiment. And in one embodiment, where the message is a CoAP message, step  2230  may be performed in accordance with step  660 , one or more steps of process  1000  of  FIG. 10 , one or more steps of process  1100  of  FIG. 11 , some combination thereof, etc. 
     As shown in  FIG. 22 , step  2240  involves determining whether the message (e.g., received in step  2210 ) is valid (e.g., based on the results of the message validation performed in step  2230 ). Step  2240  may be performed using a security component (e.g.,  112  of computer system  110 ) in one embodiment. If it is determined in step  2240  that the message (e.g., received in step  2210 ) is valid, then step  2250  may be performed. 
     Step  2250  involves accessing a data portion from the message (e.g., received in step  2210 ). The data portion may include an instance of a session key. For example, the data portion accessed in step  2250  may be or include the second data portion generated in step  1320  and/or step  2045 . And in one embodiment, the data portion accessed in step  2250  may be encrypted (e.g., ciphertext). 
     As shown in  FIG. 22 , step  2260  involves decrypting the data portion (e.g., accessed in step  2250 ) to access an instance of a session key. Decryption of the data portion in step  2260  may involve generating a plaintext version or unencrypted version of the data portion, where the plaintext version or unencrypted version of the data portion may include the instance of the session key. Step  2260  may be performed using a security component (e.g.,  112  of computer system  110 ) in one embodiment. The data portion may be decrypted in step  2260  using AES, Blowfish, RC4, the Extended Tiny Encryption Algorithm (XTEA) scheme, another symmetric-key algorithm, etc. 
     In one embodiment, the data portion (e.g., accessed in step  2250 ) may be decrypted in step  2260  using a key associated with the caller system (e.g., the first computer system or computer system  110 ). The key may be a secret key or private key that is unique to the first computer system (e.g.,  110 ) in one embodiment. The key may be stored locally at the first computer system (e.g.,  110 ) in one embodiment. For example, the key may be stored locally in a security component (e.g.,  112  of computer system  110 ), in a memory (e.g., of computer system  110 ), in a database (e.g., of computer system  110 ), etc. Alternatively, the key may be stored remotely (e.g., at another system or device) and accessed by the first computer system (e.g.,  110 ) in a secure manner in one embodiment. Accordingly, a key associated with the caller system (e.g., the first computer system or computer system  110 ) may be securely accessed and used by the caller system in step  2260  to decrypt the data portion (e.g., accessed in step  2250 ) to access the instance of the session key in one embodiment. 
     As shown in  FIG. 22 , step  2070  involves storing the instance of the session key (e.g., accessed in step  2260 ). In one embodiment, the instance of the session key may be stored locally at a caller system (e.g., the first computer system or computer system  110 ) in step  2070 . For example, the instance of the session key may be stored locally in a security component (e.g.,  112  of computer system  110 ), in a memory (e.g., of computer system  110 ), in a database (e.g., of computer system  110 ), etc. Alternatively, the instance of the session key may be stored remotely (e.g., at another system or device) in step  2070  such that the instance of the session key may be accessed by a caller system (e.g., the first computer system or computer system  110 ) in a secure manner in one embodiment. And in one embodiment, the instance of the session key may be stored in step  2070  as data  2300  of  FIG. 23 . 
       FIG. 23  shows data  2300  associated with at least one session key accessible to a caller system (e.g., the first computer system or computer system  110 ) in accordance with one embodiment. As shown in  FIG. 23 , each unique identifier in column  2310  may be associated with a respective target system that the caller system is authorized to communicate with and/or connect to (e.g., responsive to configuration of permissions in step  1305  of process  1300  and/or one or more steps of process  1500  of  FIG. 15 ). Each unique identifier (e.g., associated with a respective target system) in column  2310  may correspond to a respective key in column  2320 , where each key in column  2320  may be a session key and/or an instance of a session key (e.g., associated with communication between the caller system and a respective target system). As such, a first key (e.g., “Session Key  1 ”) may be associated with communication between the caller system and a first target system (e.g., associated with the unique identifier of “cs120”), a second key (e.g., “Session Key  4 ”) may be associated with communication between the caller system and a second target system (e.g., associated with the unique identifier of “cs150”), etc. 
     At least a portion of data  2300  may correlate to and/or be the same as permissions configuration data (e.g.,  1600  of  FIG. 16 ) in one embodiment. For example, the first row of column  2310  of data  2300  may correlate to and/or be the same as the first row of permissions configuration data  1600  (e.g., including the unique identifier of “cs120” in column  1610  and the unique identifier of “cs110” in column  1620 ). As another example, the second row of column  2310  of data  2300  may correlate to and/or be the same as the fourth row of permissions configuration data  1600  (e.g., including the unique identifier of “cs150” in column  1610  and the unique identifier of “cs110” in column  1620 ). And as yet another example, the third row of column  2310  of data  2300  may correlate to and/or be the same as the sixth row of permissions configuration data  1600  (e.g., including the unique identifier of “cs170” in column  1610  and the unique identifier of “cs110” in column  1620 ). 
     In one embodiment, data  2300  may be stored locally at a caller system (e.g., the first computer system or computer system  110 ). For example, data  2300  may be stored locally in a security component (e.g.,  112  of computer system  110 ), in a memory (e.g., of computer system  110 ), in a database (e.g., of computer system  110 ), etc. Alternatively, data  2300  may be stored remotely (e.g., at another system or device) and accessed by a caller system (e.g., the first computer system or computer system  110 ) in a secure manner in one embodiment. 
     Data  2300  may be changed or updated in one embodiment. For example, data  2300  may be changed or updated based on expiration data (e.g., associated with portion  1930  of data portion  1900 ) such as a timestamp (e.g., associated with creation of the security token and/or session key), a duration or lifetime (e.g., of the security token and/or session key), etc. In this case, a portion of data  2300  associated with at least one session key may be removed from data  2300  and/or updated (e.g., with new data corresponding to at least one new session key) responsive to expiration of the security token and/or the at least one session key. 
     Although  FIG. 23  shows data  2300  as including a particular amount of data, it should be appreciated that a different amount of data may be included in data  2300  in other embodiments. Additionally, although  FIG. 23  shows data  2300  as including a particular arrangement and type of data, it should be appreciated that a different arrangement and/or type of data may be included in data  2300  in other embodiments. 
     Turning back to  FIG. 22 , step  2280  involves performing at least one operation associated with the message. In one embodiment, step  2280  may be performed if the message (e.g., received in step  2210 ) is determined to be invalid in step  2240 . And in one embodiment, step  2280  may involve performing at least one operation using an operation component (e.g.,  116  of computer system  110 ). 
     In one embodiment, step  2280  may involve acting responsive to a message validation failure such as a triggering of a message invalidity condition (e.g., corresponding to one or more steps of process  1100 , a failure to access a unique identifier associated with the sender of the message, a failure to access a nonce from the message, determining that a nonce accessed from the message is not different from another nonce accessed from a previous message, determining that a payload of the message is not at least a predetermined size, a failure to access a key used to generate the second authentication data or otherwise perform the message validation, some combination thereof, etc.), another message validation failure (e.g., determining that the second authentication data generated based on at least a portion of the message does not correlate to authentication data accessed from the message, another message validation failure, etc.), etc. And in one embodiment, step  2280  may involve acting on a suspected or detected replay attack. 
     The at least one operation performed in step  2280  may include ignoring the message (e.g., received in step  2210 ) in one embodiment. For example, another message may not be generated and/or communicated in reply to the message (e.g., received in step  2210 ) in step  2280 . As another example, no further processing related to the message (e.g., received in step  2210 ) may be performed in step  2280 . And in one embodiment, the at least one operation performed in step  2280  may include limiting access to the recipient (e.g., the first computer system or computer system  110 ) of the sender (e.g., the third computer system or computer system  1430 ). 
     Although  FIG. 22  depicts process  2200  as including a specific number of steps, it should be appreciated that process  2200  may include a different number of steps in other embodiments. Although  FIG. 22  depicts process  2200  as including a specific ordering of steps, it should be appreciated that process  2200  may include a different ordering of steps in other embodiments. 
     Turning back to  FIG. 13A , step  1335  involves generating, at the first computer system (e.g.,  110 ), a third message including the first data portion (e.g., associated with a security token, including an instance of the session key, including at least a portion of data portion  1900 , generated in step  1320 , generated in step  2040 , some combination thereof, etc.). In one embodiment, the third message may be generated using a message generation component (e.g.,  114 ) alone or in combination with at least one other component (e.g., security component  112 , etc.). 
     In one embodiment, the third message may be generated (e.g., in step  1335 ) without decrypting the first data portion. For example, the first data portion may be accessed from the second message as ciphertext and included in the third message (e.g., as ciphertext) without decryption of the first data portion (e.g., at the first computer system). 
     The third message may be generated in step  1335  based on the results of the second processing (e.g., performed in step  1330 ) in one embodiment. For example, if the second message is valid, then the third message may be generated in step  1335 . 
     In one embodiment, the first data portion may be included in or as the payload of the third message in step  1335 . And in one embodiment, the first data portion may be included in or as another portion of the third message in step  1335 . 
     Step  1335  may involve generating authentication data to be included in the third message in one embodiment. The authentication data may be generated in step  1335  at the first computer system (e.g.,  110 ) in one embodiment. And in one embodiment, the authentication data may be generated in step  1335  using a security component (e.g.,  112  of computer system  110 ). 
     In one embodiment, the authentication data may be generated in step  1335  using an authentication mechanism such as HMAC, OAuth, OAuth 2.0, OpenID, etc. The authentication data may be generated in step  1335  using a key in one embodiment. For example, where the authentication mechanism used to generate the authentication data in step  1335  is HMAC, the authentication data may be generated by performing a hash function (e.g., MD5, SHA-1, SHA256, SHA512, etc.) on message data (e.g., a header, a token, at least one option, a payload marker, a payload, the first data portion associated with a security token, some combination thereof, etc.) using a key. And in one embodiment, the message data may be free of the key used to generate the authentication data in step  1335 . 
     An instance of the session key (e.g., accessed and/or stored in step  1330 , accessed in step  2260 , stored in step  2270 , etc.) may be used to generate the authentication data in step  1335  in one embodiment. The instance of the session key may be stored locally at the first computer system (e.g.,  110 ) in one embodiment. For example, the instance of the session key may be stored locally in a security component (e.g.,  112  of computer system  110 ), in a memory (e.g., of computer system  110 ), in a database (e.g., of computer system  110 ), etc. Alternatively, the instance of the session key may be stored remotely (e.g., at another system or device) and accessed by the first computer system (e.g.,  110 ) in a secure manner in one embodiment. Accordingly, an instance of the session key may be securely accessed and used by the first computer system (e.g.,  110 ) to generate the authentication data in step  1335  in one embodiment. 
     In one embodiment, the authentication data may be included in or as the payload of the third message in step  1335 . And in one embodiment, the authentication data may be included in or as another portion of the third message in step  1335 . 
     The third message may be a CoAP message (e.g.,  2400 A of  FIG. 24A ) in one embodiment. As shown in  FIG. 24A , CoAP message  2400 A may include data associated with a header, where the data associated with the header includes data associated with a version (e.g., “1”), a message type (e.g., “CON” or confirmable), a token length (e.g., “1” associated with a length of 1 byte), a code (e.g., a method code of “GET”), and a message identifier (e.g., “0x7a10”). Data associated with a token (e.g., “0x73”) may also be included in CoAP message  2400 A. 
     CoAP message  2400 A may include data associated with at least one option. For example, CoAP message  2400 A may include data associated with a host (e.g., an option value of “www.example.com”), data associated with a port (e.g., an option value of “5683”), data associated with a path (e.g., an option value of “keytransfer”), some combination thereof, etc. In this case, at least one option associated with CoAP message  2400 A may correspond to a URI of “coap://www.example.com:5683/keytransfer”, “coap://www.example.com/keytransfer”, “coaps://www.example.com:5683/keytransfer”, “coaps://www.example.com/keytransfer”, some combination thereof, etc. 
     The URI corresponding to at least one option associated with CoAP message  2400 A may be specific or unique to a target system (e.g., the second computer system or computer system  120 ) in one embodiment. And in one embodiment, at least one option (e.g., corresponding to an option value of “keytransfer”, corresponding to at least one other option value, etc.) associated with CoAP message  2400 A may be specific or unique to a target system (e.g., the second computer system or computer system  120 ). 
     As another example, CoAP message  2400 A may include data associated with a max-age value (e.g., an option value of “0”). In this case, a max-age value of “0” may be used to indicate that CoAP message  2400 A is not to be cached by an intermediary system or device (e.g., situated between the sender of the CoAP message  2400 A and the ultimate recipient of the CoAP message  2400 A) such as a proxy server or other type of computer system or device. 
     As a further example, CoAP message  2400 A may include data associated with a query (e.g., including one or more parameters). An option value of “uid=cs110” (e.g., associated with a first parameter) may be associated with a unique identifier (e.g., “cs110”) of a sender of CoAP message  2400 A and/or a caller system (e.g., the first computer system or computer system  110 ). An option value of “hs256=1” (e.g., associated with a second parameter) may be associated with an authentication mechanism (e.g., HMAC utilizing a hash function of SHA256) used to generate the authentication data (e.g., “Authentication Data C”) included in CoAP message  2400 A. An option value of “nonce=1” (e.g., associated with a third parameter) may be associated with a nonce (e.g., with a value of “1”) included in CoAP message  2400 A. 
     In one embodiment, one or more portions of CoAP message  2400 A may be associated with a URI including at least one parameter of a query. For example, CoAP message  2400 A may be associated with a URI of “coap://www.example.com:5683/keytransfer?uid=cs110&amp;hs256=1&amp;nonce=1”, “coap://www.example.com/keytransfer?uid=cs110&amp;hs256=1&amp;nonce=1”, “coaps://www.example.com: 5683 /keytransfer?uid=cs110&amp;hs256=1&amp;nonce=1”, “coaps://www.example.com/keytransfer?uid=cs110&amp;hs256=1&amp;nonce=1”, some combination thereof, etc. 
     CoAP message  2400 A may include data associated with at least one option length. For example, CoAP message  2400 A may include data associated with a first option length (e.g., 15 bytes) corresponding to data associated with a first option value (e.g., “www.example.com”), a second option length (e.g., 2 bytes) corresponding to data associated with a second option value (e.g., “5683”), a third option length (e.g., 11 bytes) corresponding to data associated with a third option value (e.g., “keytransfer”), etc. 
     As shown in  FIG. 24A , CoAP message  2400 A may include data associated with at least one option identifier. The at least one option identifier may include data associated with an option number and/or an option delta in one embodiment. For example, CoAP message  2400 A may include data associated with a first numerical value (e.g., “3”) as a first option identifier corresponding to a first option (e.g., associated with a host), where the first numerical value (e.g., “3”) may be the delta or difference between the current option number (e.g., “3”) and the option number of the preceding option (e.g., “0” in this case since this is the first option). As such, the first numerical value of “3” may correspond to an option number of “3.” 
     As another example, CoAP message  2400 A may include data associated with a second numerical value (e.g., “4”) as a second option identifier corresponding to a second option (e.g., associated with a port), where the second numerical value (e.g., “4”) may be the delta or difference between the current option number (e.g., “7”) and the option number of the preceding option (e.g., “3”). As such, the second numerical value of “4” may correspond to an option number of “7.” 
     As a further example, CoAP message  2400 A may include data associated with a third numerical value (e.g., “4”) as a third option identifier corresponding to a third option (e.g., associated with a path), where the third numerical value (e.g., “4”) may be the delta or difference between the current option number (e.g., “11”) and the option number of the preceding option (e.g., “7”). As such, the third numerical value of “4” may correspond to an option number of “11.” 
     As shown in  FIG. 24A , CoAP message  2400 A may include data associated with a payload marker (e.g., “0xFF”). CoAP message  2400 A may include data associated with a payload, where the data associated with a payload may include authentication data (e.g., “Authentication Data C”) and/or other data. In one embodiment, the other data may be or include the first data portion (e.g., associated with a security token, including an instance of the session key, including at least a portion of data portion  1900 , generated in step  1320 , generated in step  2040 , some combination thereof, etc.) of the second message (e.g., “Data Portion Associated With Security Token”). 
     Although  FIG. 24A  shows CoAP message  2400 A with a specific number and type of portions, it should be appreciated that CoAP message  2400 A may include a different number and/or type of portions in other embodiments. For example, CoAP message  2400 A may include fewer portions or at least one additional portion. As another example, a plurality of portions of CoAP message  2400 A may be combined into a smaller number of portions. Although  FIG. 24A  shows CoAP message  2400 A with a specific organization of portions, it should be appreciated that CoAP message  2400 A may include a different organization of portions in other embodiments. 
     CoAP message  2400 A may be free of authentication data (e.g., “Authentication Data C”) in one embodiment. Where CoAP message  2400 A is free of authentication data, CoAP message  2400 A may also be free of data associated with a max-age value. Where CoAP message  2400 A is free of authentication data, CoAP message  2400 A may be free of data associated with one or more query parameters. For example, CoAP message  2400 A may be free of a query parameter associated with a unique identifier of a sender of CoAP message  2400 A and/or a caller system, a query parameter associated with an authentication mechanism used to generate authentication data, a query parameter associated with a nonce, some combination thereof, etc. 
     In one embodiment, data associated with at least one option may be excluded from CoAP message  2400 A. For example, data (e.g., associated with a host, a port, a path, a max-age value, or some combination thereof) used by intermediary systems or devices (e.g., situated between the sender of CoAP message  2400 A and the ultimate recipient of CoAP message  2400 A) such as a proxy server or other type of computer system or device may be excluded in one or more embodiments where intermediary systems or devices do not exist or are unlikely to exist. 
     Turning back to  FIG. 13A , step  1335  may involve formatting at least one data portion (e.g., a data portion associated with a security token) of the third message in accordance with JSON (JavaScript Object Notation) in one embodiment. Alternatively, at least one data portion (e.g., a data portion associated with a security token) of the third message may be formatted in step  1335  in accordance with another format (e.g., UTF-8 plain text, link format, XML, octet-stream, etc.). Where the third message is a CoAP message (e.g.,  2400 A), the third message may include data associated with a content format (e.g., a “Content-Format” option with an option value corresponding to a format of a payload of CoAP message  2400 A, a format of a data portion associated with a security token, etc.) in one embodiment. 
     Step  1335  may be performed in accordance with one or more steps of process  2500  of  FIG. 25  in one embodiment.  FIG. 25  shows a flowchart of process  2500  for generating a message including a data portion associated with a security token in accordance with one embodiment. One or more steps of process  2500  may be performed at or by a caller system (e.g., the first computer system or computer system  110 ) in one embodiment. 
     As shown in  FIG. 25 , step  2510  involves accessing message data including a data portion associated with a security token. In one embodiment, the data portion accessed in step  2510  (e.g., as at least part of the message data) may be or include the first data portion (e.g., associated with a security token, including an instance of the session key, including at least a portion of data portion  1900 , generated in step  1320 , generated in step  2040 , some combination thereof, etc.) of the second message (e.g., received in step  1330 , step  2210 , etc.). Step  2510  may involve accessing the data portion as ciphertext without decryption of the data portion in one embodiment. And in one embodiment, step  2510  may be performed using a message generation component (e.g.,  114 ). 
     In one embodiment, the message data accessed in step  2510  may include data other than authentication data. For example, the message data may include data associated with a header (e.g., included in portion  210  of CoAP message  200 ), data associated with a token (e.g., included in portion  220  of CoAP message  200 ), data associated with at least one option (e.g., included in portion  230  of CoAP message  200 ), data associated with a payload marker (e.g., included in portion  240  of CoAP message  200 ), data associated with at least a portion of a payload (e.g., included in portion  250  of CoAP message  200 ), data other than the authentication data (e.g., “Authentication Data C” of CoAP message  2400 A), some combination thereof, etc. 
     As shown in  FIG. 25 , step  2520  involves optionally generating authentication data. In one embodiment, step  2520  may be performed using a security component (e.g.,  112  of computer system  110 ). 
     In one embodiment, the authentication data may be generated in step  2520  using an authentication mechanism such as HMAC, OAuth, OAuth 2.0, OpenID, etc. The authentication data may be generated in step  2520  using a key in one embodiment. For example, where the authentication mechanism used to generate the authentication data in step  2520  is HMAC, the authentication data may be generated by performing a hash function (e.g., MD5, SHA-1, SHA256, SHA512, etc.) on message data (e.g., accessed in step  2510 ) using a key. And in one embodiment, the message data may be free of the key used to generate the authentication data in step  2520 . 
     An instance of a session key (e.g., accessed and/or stored in step  1330 , accessed in step  2260 , stored in step  2270 , etc.) may be used to generate the authentication data in step  2520  in one embodiment. The instance of the session key may be stored locally at a caller system (e.g., the first computer system or computer system  110 ) in one embodiment. For example, the instance of the session key may be stored locally in a security component (e.g.,  112  of computer system  110 ), in a memory (e.g., of computer system  110 ), in a database (e.g., of computer system  110 ), etc. Alternatively, the instance of the session key may be stored remotely (e.g., at another system or device) and accessed by a caller system (e.g., the first computer system or computer system  110 ) in a secure manner in one embodiment. Accordingly, an instance of the session key may be securely accessed and used by a caller system (e.g., the first computer system or computer system  110 ) to generate the authentication data in step  2520  in one embodiment. 
     As shown in  FIG. 25 , step  2530  involves generating a message including the message data (e.g., accessed in step  2510 ). In one embodiment, step  2530  may involve generating a message including the message data (e.g., accessed in step  2510 ) and the authentication data (e.g., generated in step  2520 ). In one embodiment, step  2530  may be performed using a message generation component (e.g.,  114  of computer system  110 ). 
     In one embodiment, where the message generated in step  2530  is a CoAP message (e.g.,  2400 A), step  2530  may involve formatting the message data (e.g., accessed in step  2510 ) in accordance with CoAP (e.g., into one or more portions of CoAP message  200 ). The authentication data (e.g., generated in step  2520 ) may be included in or as the payload (e.g., associated with portion  250  of CoAP message  200 ) of the CoAP message in one embodiment. For example, as shown in  FIG. 24A , authentication data (e.g., “Authentication Data C”) may be included in or as the payload of CoAP message  2400 A. 
     Step  2530  may involve including the data portion associated with a security token (e.g., accessed in step  2510  as at least part of the message data) in or as the payload of the message in one embodiment. For example, as shown in  FIG. 24A , a data portion associated with a security token (e.g., “Data Portion Associated With Security Token”) may be included in or as the payload of CoAP message  2400 A in step  2530 . And in one embodiment, a data portion associated with a security token (e.g., “Data Portion Associated With Security Token”) may be included in or as another portion of the message in step  2530 . 
     In one embodiment, the message may be generated (e.g., in step  2530 ) without decrypting the data portion associated with a security token (e.g., accessed in step  2510  as at least part of the message data). For example, where the data portion (e.g., associated with a security token) is accessed (e.g., from the message received in step  2210 ) as ciphertext, the data portion may be included in the message (e.g., as ciphertext) without decryption of the data portion in step  2530 . 
     Step  2530  may involve generating a bit stream or byte stream including the message data (e.g., accessed in step  2510 ) in one embodiment. In one embodiment, step  2530  may involve generating a bit stream or byte stream including the message data (e.g., accessed in step  2510 ) and the authentication data (e.g., generated in step  2520 ). The bit stream or byte stream may be formatted in accordance with CoAP in one embodiment. 
     In one embodiment, step  2530  may involve formatting at least one data portion (e.g., a data portion associated with a security token) of the message in accordance with JSON (JavaScript Object Notation). Alternatively, at least one data portion (e.g., a data portion associated with a security token) of the message may be formatted in step  2530  in accordance with another format (e.g., UTF-8 plain text, link format, XML, octet-stream, etc.). Where the message generated in step  2530  is a CoAP message (e.g.,  2400 A), the message may include data associated with a content format (e.g., a “Content-Format” option with an option value corresponding to a format of a payload of CoAP message  2400 A, a format of a data portion associated with a security token, etc.) in one embodiment. 
     Although  FIG. 25  depicts process  2500  as including a specific number of steps, it should be appreciated that process  2500  may include a different number of steps in other embodiments. Although  FIG. 25  depicts process  2500  as including a specific ordering of steps, it should be appreciated that process  2500  may include a different ordering of steps in other embodiments. 
     As shown in  FIG. 13B , step  1340  involves communicating the third message (e.g., generated in step  1335  and/or in accordance with one or more steps of process  2500  of  FIG. 25 ) from the first computer system (e.g.,  110 ) to the second computer system (e.g.,  120 ). In one embodiment, the third message may be communicated in step  1340  over a connection (e.g.,  130  between computer system  110  and computer system  120 ). The third message may be communicated in step  1340  as a bit stream or a byte stream in one embodiment. And in one embodiment, step  1340  may involve communicating the third message using at least one communication interface (e.g.,  118  of computer system  110 ,  128  of computer system  120 , etc.). 
     In one embodiment, step  1340  may involve communicating the third message using DTLS. For example, where the third message is a CoAP message (e.g.,  2400 A), step  1340  may involve communicating the third message over CoAP using DTLS. 
     Step  1345  involves performing third processing associated with the third message, and responsive thereto, accessing an instance of the session key from the third message. In one embodiment, step  1345  may involve performing the third processing associated with the third message at the second computer system (e.g.,  120 ). For example, responsive to receiving the third message (e.g., communicated in step  1340 ), the second computer system (e.g.,  120 ) may perform the third processing. And in one embodiment, the third processing may be performed using a security component (e.g.,  122 ). 
     In one embodiment, the third processing may involve determining whether a first unique identifier associated with a caller system (e.g., the first computer system or computer system  110 ) correlates to a second unique identifier associated with the caller system. The first unique identifier associated with the caller system may be accessed from a data portion (e.g., associated with a security token, including an instance of the session key, including at least a portion of data portion  1900 , generated in step  1320 , generated in step  2040 , some combination thereof, etc.) of the third message. For example, the first unique identifier associated with the caller system may be accessed from a portion of the data portion associated with the caller system (e.g., portion  1910  of data portion  1900 ). The second unique identifier associated with the caller system (e.g., the first computer system or computer system  110 ) may be accessed from a portion of the third message other than the data portion. For example, where the data portion is included in a payload of the third message, the second unique identifier may be accessed from a portion of the third message other than the payload. As another example, where the third message is a CoAP message (e.g.,  2400 A), the second unique identifier may be accessed from data associated with an option (e.g., a “Uri-Query” option with an option value of “uid=cs110”). 
     The third processing may involve determining whether a third unique identifier associated with the target system (e.g., the second computer system or computer system  120 ) correlates to a fourth unique identifier associated with registration of the target system. The third unique identifier associated with the target system may be accessed from a data portion (e.g., associated with a security token, including an instance of the session key, including at least a portion of data portion  1900 , generated in step  1320 , generated in step  2040 , some combination thereof, etc.) of the third message. The fourth unique identifier associated with registration of the target system may correspond to registration data (e.g., accessed in step  1520  of process  1500 ) associated with the target system in one embodiment. For example, the fourth unique identifier (or data correlating thereto) may be provided, by the target system (e.g., the second computer system or computer system  120 ) or another computer system associated therewith, to the third computer system (e.g.,  1430 ) as part of registering the target system with the third computer system. 
     In one embodiment, the third processing may involve determining whether a security token (e.g., associated with a data portion of the third message) and/or a session key (e.g., corresponding to an instance of the session key included in the data portion of the third message) is valid. In one embodiment, expiration data (e.g., portion  1930  of data portion  1900 ) may be used to determine whether the security token and/or session key is valid. For example, a timestamp (e.g., associated with creation of the security token and/or session key) and a duration or lifetime (e.g., of the security token and/or session key) may be used to determine an expiration time of the security token and/or session key, where the expiration time may be compared to a current time to determine if the security token and/or session key is valid (e.g., not expired). In one embodiment, the expiration data may be accessed from a data portion (e.g., associated with a security token, including an instance of the session key, including at least a portion of data portion  1900 , generated in step  1320 , generated in step  2040 , some combination thereof, etc.) of the third message. 
     The session key (or an instance thereof) may be accessed from the third message in step  1345  based on the results of the third processing in one embodiment. For example, where the third processing includes evaluating at least one condition associated with the third message (e.g., whether a first unique identifier associated with the first computer system correlates to a second unique identifier associated with the first computer system, whether a third unique identifier associated with the second computer system correlates to a fourth unique identifier associated with the second computer system, whether the security token and/or session key is valid, some combination thereof, etc.), the session key (or an instance thereof) may be accessed in step  1345  if the at least one condition is met. In one embodiment, the session key (or an instance thereof) may be accessed in step  1345  from a data portion (e.g., associated with a security token, including an instance of the session key, including at least a portion of data portion  1900 , generated in step  1320 , generated in step  2040 , some combination thereof, etc.) of the third message. 
     In one embodiment, accessing the instance of the session key in step  1345  may involve decrypting a data portion (e.g., associated with a security token, including an instance of the session key, including at least a portion of data portion  1900 , generated in step  1320 , generated in step  2040 , some combination thereof, etc.) of the third message to access the instance of the session key. The data portion of the third message may be decrypted in step  1345  using AES, Blowfish, RC4, the Extended Tiny Encryption Algorithm (XTEA) scheme, another symmetric-key algorithm, etc. 
     In one embodiment, a key associated with the second computer system (e.g.,  120 ) may be used to decrypt the data portion of the third message in step  1345 . The key may be a secret key or private key that is unique to the second computer system (e.g.,  120 ) in one embodiment. The key may be stored locally at the second computer system (e.g.,  120 ) in one embodiment. For example, the key may be stored locally in a security component (e.g.,  122  of computer system  120 ), in a memory (e.g., of computer system  120 ), in a database (e.g., of computer system  120 ), etc. Alternatively, the key may be stored remotely (e.g., at another system or device) and accessed by the second computer system (e.g.,  120 ) in a secure manner in one embodiment. Accordingly, in one embodiment, a key associated with the second computer system (e.g.,  120 ) may be securely accessed and used by the second computer system (e.g.,  120 ) to decrypt a data portion (e.g., associated with a security token, including an instance of the session key, including at least a portion of data portion  1900 , generated in step  1320 , generated in step  2040 , some combination thereof, etc.) of the third message to access the instance of the session key in step  1345 . 
     The key used to decrypt (e.g., in step  1345 ) the data portion of the third message at the second computer system (e.g.,  120 ) may be the same key used to encrypt (e.g., in step  1320 , in step  2040 , etc.) data to form the first data portion (e.g., included in the second message) at the third computer system (e.g.,  1430 ) in one embodiment. For example, where a key associated with the second computer system (e.g., a secret key or private key that is unique to the second computer system) is used by the third computer system to encrypt the data to form the first data portion of the second message (e.g., in step  1320 , in step  2040 , etc.), the same key associated with the second computer system may be used by the second computer system to decrypt the data portion of the third message (e.g., in step  1345 ). In this manner, a symmetric-key algorithm may be used to secure a data portion (e.g., associated with a security token, including an instance of the session key, including at least a portion of data portion  1900 , generated in step  1320 , generated in step  2040 , some combination thereof, etc.) communicated using one or more messages. 
     In one embodiment, step  1345  may be performed in accordance with one or more steps of process  2600  of  FIGS. 26A and 26B .  FIGS. 26A and 26B  show a flowchart of process  2600  for performing processing associated with a message in accordance with one embodiment. One or more steps of process  2600  may be performed at or by a target system (e.g., the second computer system or computer system  120 ) in one embodiment. 
     As shown in  FIG. 26A , step  2605  involves receiving a message. In one embodiment, the message received in step  2605  may be the message generated in step  1335 , generated in step  2530 , communicated in step  1340 , some combination thereof, etc. Step  2605  may involve receiving the message at the target system (e.g., the second computer system or computer system  120 ) from another computer system (e.g.,  110 , another system or device, etc.) in one embodiment. 
     In one embodiment, the message may be received in step  2605  over a connection (e.g.,  130 ). The message may be received in step  2605  as a bit stream or a byte stream in one embodiment. And in one embodiment, step  2605  may involve receiving the message using a communication interface (e.g.,  128 ). 
     As shown in  FIG. 26A , step  2610  involves accessing, from the message (e.g., received in step  2605 ), a data portion associated with a security token. In one embodiment, the data portion accessed in step  2610  may include an instance of the session key, include at least a portion of data portion  1900 , be generated in step  1320 , be generated in step  2040 , some combination thereof, etc. And in one embodiment, step  2610  may be performed using a security component (e.g.,  122 ). 
     Step  2615  involves decrypting the data portion (e.g., accessed in step  2610 ). Decryption of the data portion in step  2615  may involve generating a plaintext version or unencrypted version of the data portion. Step  2615  may be performed using a security component (e.g.,  122  of computer system  120 ) in one embodiment. The data portion may be decrypted in step  2615  using AES, Blowfish, RC4, the Extended Tiny Encryption Algorithm (XTEA) scheme, another symmetric-key algorithm, etc. 
     In one embodiment, the data portion (e.g., accessed in step  2610 ) may be decrypted in step  2615  using a key associated with the target system (e.g., the second computer system or computer system  120 ). For example, the key may be a secret key or private key that is unique to the second computer system (e.g.,  120 ). The key may be stored locally at the second computer system (e.g.,  120 ) in one embodiment. For example, the key may be stored locally in a security component (e.g.,  122  of computer system  120 ), in a memory (e.g., of computer system  120 ), in a database (e.g., of computer system  120 ), etc. Alternatively, the key may be stored remotely (e.g., at another system or device) and accessed by the second computer system (e.g.,  120 ) in a secure manner in one embodiment. Accordingly, a key associated with the target system (e.g., the second computer system or computer system  120 ) may be securely accessed and used by the target system in step  2615  to decrypt the data portion (e.g., accessed in step  2610 ) in one embodiment. 
     As shown in  FIG. 26A , step  2620  involves accessing, from the data portion (e.g., accessed in step  2610 ), a first unique identifier associated with a caller system (e.g., the first computer system or computer system  110 ). Step  2620  may be performed using a security component (e.g.,  122  of computer system  120 ) in one embodiment. In one embodiment, step  2620  may involve accessing the first unique identifier from a plaintext version or unencrypted version of the data portion (e.g., generated responsive to decryption of the data portion in step  2615 ). And in one embodiment, the first unique identifier may be accessed in step  2620  from a portion of the data portion associated with the caller system (e.g., portion  1910  of data portion  1900 ). 
     Step  2625  involves accessing, from a portion of the message (e.g., received in step  2605 ) other than the data portion (e.g., accessed in step  2610 ), a second unique identifier associated with the caller system (e.g., the first computer system or computer system  110 ). For example, where the data portion (e.g., accessed in step  2610 ) is included in a payload of the message, the second unique identifier may be accessed in step  2625  from a portion of the message other than the payload. As another example, where the message is a CoAP message (e.g.,  2400 A), the second unique identifier may be accessed in step  2625  from data associated with an option (e.g., a “Uri-Query” option with an option value of “uid=cs110”). In one embodiment, step  2625  may be performed using a security component (e.g.,  122  of computer system  120 ). 
     As shown in  FIG. 26A , step  2630  involves determining whether the first unique identifier (e.g., accessed in step  2620 ) correlates to the second unique identifier (e.g., accessed in step  2625 ). In one embodiment, step  2630  may be performed using a security component (e.g.,  122  of computer system  120 ). If the first unique identifier correlates to the second unique identifier, then step  2635  may be performed. 
     Step  2635  involves accessing, from the data portion (e.g., accessed in step  2610 ), a third unique identifier associated with a target system (e.g., the second computer system or computer system  120 ). Step  2635  may be performed using a security component (e.g.,  122  of computer system  120 ) in one embodiment. In one embodiment, step  2635  may involve accessing the third unique identifier from a plaintext version or unencrypted version of the data portion (e.g., generated responsive to decryption of the data portion in step  2615 ). And in one embodiment, the third unique identifier may be accessed in step  2635  from a portion of the data portion associated with the target system (e.g., portion  1920  of data portion  1900 ). 
     As shown in  FIG. 26B , step  2640  involves accessing a fourth unique identifier associated with registration of the target system (e.g., the second computer system or computer system  120 ). The fourth unique identifier associated with registration of the target system may correspond to registration data (e.g., accessed in step  1520  of process  1500 ) associated with the target system in one embodiment. For example, the fourth unique identifier (or data correlating thereto) may be provided, by the target system (e.g., the second computer system or computer system  120 ) or another computer system associated therewith, to the third computer system (e.g.,  1430 ) as part of registering the target system with the third computer system. 
     Step  2640  may involve accessing the fourth unique identifier locally from a component of the target system (e.g., security component  122 , a memory of computer system  120 , a database of computer system  120 , etc.), remotely from another system or device accessible to the target system, from the third computer system (e.g.,  1430 ), etc. In one embodiment, step  2640  may be performed using a security component (e.g.,  122  of computer system  120 ). 
     As shown in  FIG. 26B , step  2645  involves determining whether the third unique identifier (e.g., accessed in step  2635 ) correlates to the fourth unique identifier (e.g., accessed in step  2640 ). In one embodiment, step  2645  may be performed using a security component (e.g.,  122  of computer system  120 ). If the third unique identifier correlates to the fourth unique identifier, then step  2650  may be performed. 
     Step  2650  involves accessing, from the data portion (e.g., accessed in step  2610 ), expiration data. In one embodiment, step  2650  may be performed using a security component (e.g.,  122  of computer system  120 ). And in one embodiment, the expiration data may be accessed in step  2650  from a portion of the data portion associated with expiration data (e.g., portion  1930  of data portion  1900 ). 
     In one embodiment, the expiration data may be associated with a security token (e.g., associated with the data portion accessed in step  2610 ) and/or a session key (e.g., corresponding to an instance of a session key included in the data portion accessed in step  2610 ). In one embodiment, the expiration data may include a timestamp (e.g., associated with creation of the security token and/or session key), a duration or lifetime (e.g., of the security token and/or session key), other data, some combination thereof, etc. Where the expiration data includes a timestamp, the timestamp may be a UTC timestamp, unix timestamp, epoch timestamp, another type of timestamp, etc. Where the expiration data includes a duration or lifetime, the duration or lifetime may include a timeout. 
     The duration or lifetime may be set or determined by the target system (e.g., the second computer system or computer system  120 ) or another computer system associated therewith in one embodiment. For example, the target system (e.g., the second computer system or computer system  120 ) or another computer system associated therewith may communicate information about the duration or lifetime to the third computer system (e.g.,  1430 ), where the third computer system may access and/or store the information about the duration or lifetime (e.g., for generation of and/or inclusion in portion  1930 ). 
     As shown in  FIG. 26B , step  2655  involves determining whether the security token and/or session key are valid. In one embodiment, step  2655  may be performed using a security component (e.g.,  122  of computer system  120 ). In one embodiment, step  2655  may involve determining whether the security token and/or session key are valid based on the expiration data (e.g., accessed in step  2650 ). If the security token and/or session key are determined to be valid in step  2655 , then step  2660  may be performed. 
     Step  2660  involves accessing, from the data portion (e.g., accessed in step  2610 ), an instance of a session key. In one embodiment, step  2660  may be performed using a security component (e.g.,  122  of computer system  120 ). And in one embodiment, the instance of the session key may be accessed in step  2660  from a portion of the data portion associated with an instance of a session key (e.g., portion  1940  of data portion  1900 ). 
     As shown in  FIG. 26B , step  2665  involves storing the instance of the session key (e.g., accessed in step  2660 ). In one embodiment, the instance of the session key may be stored locally at a target system (e.g., the second computer system or computer system  120 ) in step  2665 . For example, the instance of the session key may be stored locally in a security component (e.g.,  122  of computer system  120 ), in a memory (e.g., of computer system  120 ), in a database (e.g., of computer system  120 ), etc. Alternatively, the instance of the session key may be stored remotely (e.g., at another system or device) in step  2665  such that the instance of the session key may be accessed by a target system (e.g., the second computer system or computer system  120 ) in a secure manner in one embodiment. And in one embodiment, the instance of the session key may be stored in step  2665  as data  2700  of  FIG. 27 . 
       FIG. 27  shows data  2700  associated with at least one session key accessible to a target system (e.g., the second computer system or computer system  120 ) in accordance with one embodiment. As shown in  FIG. 27 , each unique identifier in column  2710  may be associated with a respective caller system that is authorized to communicate with and/or connect to the target system (e.g., responsive to configuration of permissions in step  1305  of process  1300  and/or one or more steps of process  1500  of  FIG. 15 ). Each unique identifier (e.g., associated with a respective caller system) in column  2710  may correspond to a respective key in column  2720 , where each key in column  2720  may be a session key and/or an instance of a session key (e.g., associated with communication between the target system and a respective caller system). As such, a first key (e.g., “Session Key 1”) may be associated with communication between the target system and a first caller system (e.g., associated with the unique identifier of “cs110”), a second key (e.g., “Session Key 2”) may be associated with communication between the target system and a second caller system (e.g., associated with the unique identifier of “cs130”), etc. 
     At least a portion of data  2700  may correlate to and/or be the same as permissions configuration data (e.g.,  1600  of  FIG. 16 ) in one embodiment. For example, the first row of column  2710  of data  2700  may correlate to and/or be the same as the first row of permissions configuration data  1600  (e.g., including the unique identifier of “cs120” in column  1610  and the unique identifier of “cs110” in column  1620 ). As another example, the second row of column  2710  of data  2700  may correlate to and/or be the same as the second row of permissions configuration data  1600  (e.g., including the unique identifier of “cs120” in column  1610  and the unique identifier of “cs130” in column  1620 ). And as yet another example, the third row of column  2710  of data  2700  may correlate to and/or be the same as the third row of permissions configuration data  1600  (e.g., including the unique identifier of “cs120” in column  1610  and the unique identifier of “cs140” in column  1620 ). 
     In one embodiment, data  2700  may be stored locally at a target system (e.g., the second computer system or computer system  120 ). For example, data  2700  may be stored locally in a security component (e.g.,  122  of computer system  120 ), in a memory (e.g., of computer system  120 ), in a database (e.g., of computer system  120 ), etc. Alternatively, data  2700  may be stored remotely (e.g., at another system or device) and accessed by a target system (e.g., the second computer system or computer system  120 ) in a secure manner in one embodiment. 
     Data  2700  may be changed or updated in one embodiment. For example, data  2700  may be changed or updated based on expiration data (e.g., associated with portion  1930  of data portion  1900 ) such as a timestamp (e.g., associated with creation of the security token and/or session key), a duration or lifetime (e.g., of the security token and/or session key), etc. In this case, a portion of data  2700  associated with at least one session key may be removed from data  2700  and/or updated (e.g., with new data corresponding to at least one new session key) responsive to expiration of the security token and/or the at least one session key. 
     Although  FIG. 27  shows data  2700  as including a particular amount of data, it should be appreciated that a different amount of data may be included in data  2700  in other embodiments. Additionally, although  FIG. 27  shows data  2700  as including a particular arrangement and type of data, it should be appreciated that a different arrangement and/or type of data may be included in data  2700  in other embodiments. 
     Turning back to  FIG. 26B , step  2670  involves performing at least one operation associated with the message. In one embodiment, step  2670  may be performed if it is determined in step  2630  that the first unique identifier does not correlate to the second unique identifier. In one embodiment, step  2670  may be performed if it is determined in step  2645  that the third unique identifier does not correlate to the fourth unique identifier. And in one embodiment, step  2670  may be performed if it is determined in step  2655  that the security token and/or the session key are invalid (e.g., expired). And in one embodiment, step  2670  may involve performing at least one operation using an operation component (e.g.,  126  of computer system  120 ). 
     The at least one operation performed in step  2670  may include ignoring the message (e.g., received in step  2605 ) in one embodiment. For example, another message may not be generated and/or communicated in reply to the message (e.g., received in step  2605 ) in step  2670 . As another example, no further processing related to the message (e.g., received in step  2605 ) may be performed in step  2670 . And in one embodiment, the at least one operation performed in step  2670  may include limiting access to the recipient (e.g., the second computer system or computer system  120 ) of the sender (e.g., the first computer system or computer system  110 ). 
     Although  FIGS. 26A and 26B  depict process  2600  as including a specific number of steps, it should be appreciated that process  2600  may include a different number of steps in other embodiments. Although  FIGS. 26A and 26B  depict process  2600  as including a specific ordering of steps, it should be appreciated that process  2600  may include a different ordering of steps in other embodiments. 
     Turning back to  FIG. 13B , step  1350  involves optionally performing message validation with respect to the third message (e.g., communicated in step  1340 ). In one embodiment, step  1350  may be performed if the third message includes authentication data, whereas step  1350  may be bypassed or omitted if the third message does not include authentication data. In one embodiment, step  1350  may be performed at the second computer system (e.g.,  120 ). In one embodiment, the message validation may be performed in step  1350  using a security component (e.g.,  122 ). And in one embodiment, step  1350  may be performed in accordance with one or more steps of process  2800  of  FIG. 28 . 
       FIG. 28  shows a flowchart of process  2800  for performing message validation in accordance with one embodiment. One or more steps of process  2800  may be performed responsive to one or more steps of process  2600  in one embodiment. For example, if an instance of a session key is accessed (e.g., in step  2660 ) and/or stored (e.g., in step  2665 ), then one or more steps of process  2800  may be performed. And in one embodiment, one or more steps of process  2800  may be performed at or by a target system (e.g., the second computer system or computer system  120 ). 
     As shown in  FIG. 28 , step  2810  involves processing a message. In one embodiment, the message processed in step  2810  may be the message generated in step  1335 , generated in step  2530 , communicated in step  1340 , received in step  2605 , some combination thereof, etc. Processing of the message in step  2810  may involve accessing authentication data from the message in one embodiment. In one embodiment, step  2810  may involve processing the message using a security component (e.g.,  122  of computer system  120 ). And in one embodiment, where the message is a CoAP message, step  2810  may be performed in accordance with step  650  and/or one or more steps of process  900  of  FIG. 9 . 
     Step  2820  involves performing message validation (e.g., with respect to the message processed in step  2810 ). The message validation may be used to verify the authenticity of the sender of the message and/or the integrity of the message. Where the message includes a nonce, the message validation may be used to detect a replay attack. 
     In one embodiment, message validation may be performed in step  2820  based on authentication data (e.g., accessed from the message in step  2810 ). And in one embodiment, message validation may be performed in step  2820  using at least one message invalidity condition. 
     Where message validation is performed based on authentication data, message validation may be performed in step  2820  by comparing second authentication data to the authentication data in one embodiment. For example, the target system (e.g., the second computer system or computer system  120 ) may generate second authentication data based on at least a portion of the message (e.g., a header, a token, at least one option, a payload marker, a payload, a data portion associated with a security token, some combination thereof, etc.). The second authentication data may be compared to the authentication data (e.g., included in the message and/or accessed in step  2810 ) to verify the authenticity of the sender of the message (e.g., the first computer system or computer system  110 ), verify the integrity of the message, detect and/or act on a replay attack, some combination thereof, etc. 
     In one embodiment, the second authentication data may be generated in step  2820  using an authentication mechanism such as HMAC, OAuth, OAuth 2.0, OpenID, etc. The second authentication data may be generated in step  2820  using a key in one embodiment. For example, where the authentication mechanism used to generate the second authentication data in step  2820  is HMAC, the second authentication data may be generated by performing a hash function (e.g., MD5, SHA-1, SHA256, SHA512, etc.) on at least a portion of the message (e.g., a header, a token, at least one option, a payload marker, a payload, a data portion associated with a security token, some combination thereof, etc.) using a key. And in one embodiment, the message may be free of the key used to generate the second authentication data in step  2820 . 
     An instance of a session key (e.g., accessed and/or stored in step  1345 , accessed in step  2660 , stored in step  2665 , etc.) may be used to generate the second authentication data in step  2820  in one embodiment. The instance of the session key may be stored locally at a target system (e.g., the second computer system or computer system  120 ) in one embodiment. For example, the instance of the session key may be stored locally in a security component (e.g.,  122  of computer system  120 ), in a memory (e.g., of computer system  120 ), in a database (e.g., of computer system  120 ), etc. Alternatively, the instance of the session key may be stored remotely (e.g., at another system or device) and accessed by a target system (e.g., the second computer system or computer system  120 ) in a secure manner in one embodiment. Accordingly, an instance of a session key may be securely accessed and used by a target system (e.g., the second computer system or computer system  120 ) to generate the second authentication data in step  2820  in one embodiment. 
     Where message validation is performed using at least one message invalidity condition, the message may be determined to be invalid in step  2820  if any of the at least one message invalidity condition is triggered in one embodiment. For example, the message may be determined to be invalid in step  2820  responsive to a failure to access a unique identifier associated with the sender of the message (e.g., the first computer system or computer system  110 ). As another example, the message may be determined to be invalid in step  2820  responsive to a failure to access a nonce from the message. As a further example, the message may be determined to be invalid in step  2820  responsive to determining that a nonce accessed from the message is not different from another nonce accessed from a previous message. As yet another example, the message may be determined to be invalid in step  2820  responsive to determining that a payload of the message is not at least a predetermined size. And as another example, the message may be determined to be invalid in step  2820  responsive to a failure to access a key (e.g., an instance of the session key) used to generate the second authentication data or otherwise perform the message validation. 
     The message validation may be performed in step  2820  using a security component (e.g.,  122  of computer system  120 ) in one embodiment. And in one embodiment, where the message is a CoAP message, step  2820  may be performed in accordance with step  660 , one or more steps of process  1000  of  FIG. 10 , one or more steps of process  1100  of  FIG. 11 , some combination thereof, etc. 
     As shown in  FIG. 28 , step  2830  involves determining whether the message (e.g., processed in step  2810 ) is valid (e.g., based on the results of the message validation performed in step  2820 ). Step  2830  may be performed using a security component (e.g.,  122  of computer system  120 ) in one embodiment. If it is determined in step  2830  that the message (e.g., processed in step  2810 ) is valid, then step  2840  may be performed. 
     Step  2840  involves performing at least one operation associated with the message (e.g., processed in step  2810 ). In one embodiment, step  2840  may involve performing at least one operation associated with communication between the caller system (e.g., the first computer system or computer system  110 ) and the target system (e.g., the second computer system or computer system  120 ). And in one embodiment, step  2840  may involve performing one or more steps of process  1300  (e.g., step  1355 , step  1360 , step  1365 , step  1370 , another step of process  1300 , some combination thereof, etc.). 
     Alternatively, if it is determined in step  2830  that the message (e.g., processed in step  2810 ) is not valid, then at least one other operation associated with the message may be performed in step  2850 . 
       2850  involves performing at least one other operation associated with the message. In one embodiment, step  2850  may be performed if the message (e.g., processed in step  2810 ) is determined to be invalid in step  2830 . And in one embodiment, step  2850  may involve performing at least one operation using an operation component (e.g.,  126  of computer system  120 ). 
     In one embodiment, step  2850  may involve acting responsive to a message validation failure such as a triggering of a message invalidity condition (e.g., corresponding to one or more steps of process  1100 , a failure to access a unique identifier associated with the sender of the message, a failure to access a nonce from the message, determining that a nonce accessed from the message is not different from another nonce accessed from a previous message, determining that a payload of the message is not at least a predetermined size, a failure to access a key used to generate the second authentication data or otherwise perform the message validation, some combination thereof, etc.), another message validation failure (e.g., determining that the second authentication data generated based on at least a portion of the message does not correlate to authentication data accessed from the message, another message validation failure, etc.), etc. And in one embodiment, step  2850  may involve acting on a suspected or detected replay attack. 
     The at least one other operation performed in step  2850  may include ignoring the message (e.g., processed in step  2810 ) in one embodiment. For example, another message may not be generated and/or communicated in reply to the message (e.g., processed in step  2810 ) in step  2850 . As another example, no further processing related to the message (e.g., processed in step  2810 ) may be performed in step  2850 . And in one embodiment, the at least one other operation performed in step  2850  may include limiting access to the recipient (e.g., the second computer system or computer system  120 ) of the sender (e.g., the first computer system or computer system  110 ). 
     In one embodiment, where step  2850  is performed before the storing of an instance of a session key (e.g., in step  2665  of process  2600 ), the at least one other operation performed in step  2850  may involve deleting, destroying, and/or taking no further action with respect to the instance of the session key (e.g., accessed in step  2660 ). In this case, step  2665  may be bypassed or omitted. 
     Although  FIG. 28  depicts process  2800  as including a specific number of steps, it should be appreciated that process  2800  may include a different number of steps in other embodiments. Although  FIG. 28  depicts process  2800  as including a specific ordering of steps, it should be appreciated that process  2800  may include a different ordering of steps in other embodiments. 
     Turning back to  FIG. 13B , step  1355  involves optionally generating, at the second computer system (e.g.,  120 ), a fourth message associated with an indication of successful access of the session key from the third message (e.g., in step  1345 , in step  2660 , etc.). In one embodiment, the fourth message may be generated using a message generation component (e.g.,  124 ) alone or in combination with at least one other component (e.g., security component  122 , etc.). 
     In one embodiment, the third message may be generated in step  1355  based on the results of the third processing (e.g., performed in step  1345 ) and/or the results of the optional message validation performed with respect to the third message (e.g., in step  1350 ). For example, if at least one condition associated with the third message is met and/or if the third message is valid, then the fourth message may be generated in step  1355 . 
     In one embodiment, data associated with an indication of successful access of the session key may be included in or as the payload of the fourth message in step  1355 . And in one embodiment, data associated with an indication of successful access of the session key may be included in or as another portion of the fourth message in step  1355 . 
     Step  1355  may involve generating authentication data to be included in the fourth message in one embodiment. And in one embodiment, the authentication data may be generated in step  1355  using a security component (e.g.,  122  of computer system  120 ). 
     In one embodiment, the authentication data may be generated in step  1355  using an authentication mechanism such as HMAC, OAuth, OAuth 2.0, OpenID, etc. The authentication data may be generated in step  1355  using a key in one embodiment. For example, where the authentication mechanism used to generate the authentication data in step  1355  is HMAC, the authentication data may be generated by performing a hash function (e.g., MD5, SHA-1, SHA256, SHA512, etc.) on message data (e.g., a header, a token, at least one option, a payload marker, a payload, data associated with an indication of successful access of the session key, some combination thereof, etc.) using a key. And in one embodiment, the message data may be free of the key used to generate the authentication data in step  1355 . 
     An instance of the session key (e.g., accessed and/or stored in step  1345 , accessed in step  2660 , stored in step  2665 , etc.) may be used to generate the authentication data in step  1355  in one embodiment. The instance of the session key may be stored locally at the second computer system (e.g.,  120 ) in one embodiment. For example, the instance of the session key may be stored locally in a security component (e.g.,  122  of computer system  120 ), in a memory (e.g., of computer system  120 ), in a database (e.g., of computer system  120 ), etc. Alternatively, the instance of the session key may be stored remotely (e.g., at another system or device) and accessed by the second computer system (e.g.,  120 ) in a secure manner in one embodiment. Accordingly, an instance of the session key may be securely accessed and used by the second computer system (e.g.,  120 ) to generate the authentication data in step  1355  in one embodiment. 
     In one embodiment, the authentication data may be included in or as the payload of the fourth message in step  1355 . And in one embodiment, the authentication data may be included in or as another portion of the fourth message in step  1355 . 
     The fourth message may be a CoAP message (e.g.,  2400 B of  FIG. 24B ) in one embodiment. As shown in  FIG. 24B , CoAP message  2400 B may include data associated with a header, where the data associated with the header includes data associated with a version (e.g., “1”), a message type (e.g., “ACK” or acknowledgement), a token length (e.g., “1” associated with a length of 1 byte), a code (e.g., a response code of “Content”), and a message identifier (e.g., “0x7a10”). Data associated with a token (e.g., “0x73”) may also be included in CoAP message  2400 B. 
     CoAP message  2400 B may include data associated with at least one option. For example, CoAP message  2400 B may include data associated with a max-age value (e.g., an option value of “0”). In this case, a max-age value of “0” may be used to indicate that CoAP message  2400 B is not to be cached by an intermediary system or device (e.g., situated between the sender of the CoAP message  2400 B and the ultimate recipient of the CoAP message  2400 B) such as a proxy server or other type of computer system or device. 
     As another example, CoAP message  2400 B may include data associated with a query (e.g., including one or more parameters). An option value of “uid=cs120” (e.g., associated with a first parameter) may be associated with a unique identifier (e.g., “cs120”) of a sender of CoAP message  2400 B (e.g., computer system  120 ). An option value of “hs256=1” (e.g., associated with a second parameter) may be associated with an authentication mechanism (e.g., HMAC utilizing a hash function of SHA256) used to generate the authentication data (e.g., “Authentication Data D”) included in CoAP message  2400 B. An option value of “nonce=1” (e.g., associated with a third parameter) may be associated with a nonce (e.g., with a value of “1”) included in CoAP message  2400 B. 
     CoAP message  2400 B may include data associated with at least one option length. For example, CoAP message  2400 B may include data associated with a first option length (e.g., 1 byte) corresponding to data associated with a first option value (e.g., “0”), a second option length (e.g., 9 bytes) corresponding to data associated with a second option value (e.g., “uid=cs120”), a third option length (e.g., 7 bytes) corresponding to data associated with a third option value (e.g., “hs256=1”), etc. 
     As shown in  FIG. 24B , CoAP message  2400 B may include data associated with at least one option identifier. The at least one option identifier may include data associated with an option number and/or an option delta in one embodiment. For example, CoAP message  2400 B may include data associated with a first numerical value (e.g., “14”) as a first option identifier corresponding to a first option (e.g., associated with a max-age value), where the first numerical value (e.g., “14”) may be the delta or difference between the current option number (e.g., “14”) and the option number of the preceding option (e.g., “0” in this case since this is the first option). As such, the first numerical value of “14” may correspond to an option number of “14.” 
     As another example, CoAP message  2400 B may include data associated with a second numerical value (e.g., “1”) as a second option identifier corresponding to a second option (e.g., associated with a query), where the second numerical value (e.g., “1”) may be the delta or difference between the current option number (e.g., “15”) and the option number of the preceding option (e.g., “14”). As such, the second numerical value of “1” may correspond to an option number of “15.” 
     As a further example, CoAP message  2400 B may include data associated with a third numerical value (e.g., “0”) as a third option identifier corresponding to a third option (e.g., associated with a query), where the third numerical value (e.g., “0”) may be the delta or difference between the current option number (e.g., “15”) and the option number of the preceding option (e.g., “15”). As such, the third numerical value of “0” may correspond to an option number of “15.” 
     As shown in  FIG. 24B , CoAP message  2400 B may include data associated with a payload marker (e.g., “0xFF”). CoAP message  2400 B may include data associated with a payload, where the data associated with a payload may include authentication data (e.g., “Authentication Data D”) and/or other data. In one embodiment, the other data may include data associated with an indication of successful access of the session key (e.g., depicted in  FIG. 24B  as the data or content of “Key Transfer Successful”). 
     CoAP message  2400 A and CoAP message  2400 B may share a common message identifier (e.g., “0x7a10”) in one embodiment. CoAP message  2400 A and CoAP message  2400 B may share a common token (e.g., “0x73”) in one embodiment. 
     In one embodiment, a message type associated with CoAP message  2400 B (e.g., “ACK” or acknowledgement) may correspond to and/or be determined by a message type associated with CoAP message  2400 A (e.g., “CON” or confirmable). And in one embodiment, a response code associated with CoAP message  2400 B (e.g., “Content”) may correspond to and/or be determined by a method code associated with CoAP message  2400 A (e.g., “GET”). In this case, CoAP message  2400 B may include data associated with the request of CoAP message  2400 A (e.g., data associated with an indication of successful access of the session key). 
     Although  FIG. 24B  shows CoAP message  2400 B with a specific number and type of portions, it should be appreciated that CoAP message  2400 B may include a different number and/or type of portions in other embodiments. For example, CoAP message  2400 B may include fewer portions or at least one additional portion. As another example, a plurality of portions of CoAP message  2400 B may be combined into a smaller number of portions. Although  FIG. 24B  shows CoAP message  2400 B with a specific organization of portions, it should be appreciated that CoAP message  2400 B may include a different organization of portions in other embodiments. 
     CoAP message  2400 B may be free of authentication data (e.g., “Authentication Data D”) in one embodiment. Where CoAP message  2400 B is free of authentication data, CoAP message  2400 B may also be free of data associated with a max-age value. Where CoAP message  2400 B is free of authentication data, CoAP message  2400 B may be free of data associated with one or more query parameters. For example, CoAP message  2400 B may be free of a query parameter associated with a unique identifier of a sender of CoAP message  2400 B and/or a target system, a query parameter associated with an authentication mechanism used to generate authentication data, a query parameter associated with a nonce, some combination thereof, etc. 
     In one embodiment, data associated with at least one option may be excluded from CoAP message  2400 B. For example, data (e.g., associated with a host, a port, a path, a max-age value, or some combination thereof) used by intermediary systems or devices (e.g., situated between the sender of CoAP message  2400 B and the ultimate recipient of CoAP message  2400 B) such as a proxy server or other type of computer system or device may be excluded in one or more embodiments where intermediary systems or devices do not exist or are unlikely to exist. 
     Turning back to  FIG. 13B , step  1355  may be performed in accordance with one or more steps of process  2900  of  FIG. 29  in one embodiment.  FIG. 29  shows a flowchart of process  2900  for generating a message associated with successful access of a session key in accordance with one embodiment. In one embodiment, one or more steps of process  2900  may be performed at or by a target system (e.g., the second computer system or computer system  120 ). 
     As shown in  FIG. 29 , step  2910  involves accessing message data including data associated with an indication of successful access of the session key. In one embodiment, step  2510  may be performed using a message generation component (e.g.,  124 ). 
     In one embodiment, the message data accessed in step  2910  may include data other than authentication data. For example, the message data may include data associated with a header (e.g., included in portion  210  of CoAP message  200 ), data associated with a token (e.g., included in portion  220  of CoAP message  200 ), data associated with at least one option (e.g., included in portion  230  of CoAP message  200 ), data associated with a payload marker (e.g., included in portion  240  of CoAP message  200 ), data associated with at least a portion of a payload (e.g., included in portion  250  of CoAP message  200 ), data other than the authentication data (e.g., “Authentication Data D” of CoAP message  2400 B), some combination thereof, etc. 
     As shown in  FIG. 29 , step  2920  involves optionally generating authentication data. In one embodiment, step  2920  may be performed using a security component (e.g.,  122  of computer system  120 ). 
     In one embodiment, the authentication data may be generated in step  2920  using an authentication mechanism such as HMAC, OAuth, OAuth 2.0, OpenID, etc. The authentication data may be generated in step  2920  using a key in one embodiment. For example, where the authentication mechanism used to generate the authentication data in step  2920  is HMAC, the authentication data may be generated by performing a hash function (e.g., MD5, SHA-1, SHA256, SHA512, etc.) on message data (e.g., accessed in step  2910 ) using a key. And in one embodiment, the message data may be free of the key used to generate the authentication data in step  2920 . 
     An instance of a session key (e.g., accessed and/or stored in step  1345 , accessed in step  2660 , stored in step  2665 , etc.) may be used to generate the authentication data in step  2920  in one embodiment. The instance of the session key may be stored locally at a target system (e.g., the second computer system or computer system  120 ) in one embodiment. For example, the instance of the session key may be stored locally in a security component (e.g.,  122  of computer system  120 ), in a memory (e.g., of computer system  120 ), in a database (e.g., of computer system  120 ), etc. Alternatively, the instance of the session key may be stored remotely (e.g., at another system or device) and accessed by a target system (e.g., the second computer system or computer system  120 ) in a secure manner in one embodiment. Accordingly, an instance of the session key may be securely accessed and used by a target system (e.g., the second computer system or computer system  120 ) to generate the authentication data in step  2920  in one embodiment. 
     As shown in  FIG. 29 , step  2930  involves generating a message including the message data (e.g., accessed in step  2910 ). In one embodiment, step  2930  may involve generating a message including the message data (e.g., accessed in step  2910 ) and the authentication data (e.g., generated in step  2920 ). In one embodiment, step  2930  may be performed using a message generation component (e.g.,  124  of computer system  120 ). 
     In one embodiment, where the message generated in step  2930  is a CoAP message (e.g.,  2400 B), step  2930  may involve formatting the message data (e.g., accessed in step  2910 ) in accordance with CoAP (e.g., into one or more portions of CoAP message  200 ). The authentication data (e.g., generated in step  2920 ) may be included in or as the payload (e.g., associated with portion  250  of CoAP message  200 ) of the CoAP message in one embodiment. For example, as shown in  FIG. 24B , authentication data (e.g., “Authentication Data D”) may be included in or as the payload of CoAP message  2400 B. 
     Step  2930  may involve including the data associated with an indication of successful access of the session key (e.g., accessed in step  2910  as at least part of the message data) in or as the payload of the message in one embodiment. For example, as shown in  FIG. 24B , data associated with an indication of successful access of the session key (e.g., the data or content of “Key Transfer Successful”) may be included in or as the payload of CoAP message  2400 B in step  2930 . And in one embodiment, data associated with an indication of successful access of the session key (e.g., the data or content of “Key Transfer Successful”) may be included in or as another portion of the message in step  2930 . 
     In one embodiment, step  2930  may involve generating a bit stream or byte stream including the message data (e.g., accessed in step  2910 ). In one embodiment, step  2930  may involve generating a bit stream or byte stream including the message data (e.g., accessed in step  2910 ) and the authentication data (e.g., generated in step  2920 ). The bit stream or byte stream may be formatted in accordance with CoAP in one embodiment. 
     Although  FIG. 29  depicts process  2900  as including a specific number of steps, it should be appreciated that process  2900  may include a different number of steps in other embodiments. Although  FIG. 29  depicts process  2900  as including a specific ordering of steps, it should be appreciated that process  2900  may include a different ordering of steps in other embodiments. 
     Turning back to  FIG. 13B , step  1360  involves optionally communicating the fourth message (e.g., generated in step  1355  and/or in accordance with one or more steps of process  2900  of  FIG. 29 ) from the second computer system (e.g.,  120 ) to the first computer system (e.g.,  110 ). In one embodiment, the fourth message may be communicated in step  1360  over a connection (e.g.,  130  between computer system  110  and computer system  120 ). The fourth message may be communicated in step  1360  as a bit stream or a byte stream in one embodiment. And in one embodiment, step  1360  may involve communicating the fourth message using at least one communication interface (e.g.,  118  of computer system  110 ,  128  of computer system  120 , etc.). 
     In one embodiment, step  1360  may involve communicating the fourth message using DTLS. For example, where the fourth message is a CoAP message (e.g.,  2400 B), step  1360  may involve communicating the fourth message over CoAP using DTLS. 
     Step  1365  involves optionally performing fourth processing associated with the fourth message. In one embodiment, step  1365  may involve performing the fourth processing associated with the fourth message at the first computer system (e.g.,  110 ). For example, responsive to receiving the fourth message (e.g., communicated in step  1360 ), the first computer system (e.g.,  110 ) may perform the fourth processing. And in one embodiment, the fourth processing may be performed using a security component (e.g.,  112 ). 
     Where the fourth message includes authentication data, the fourth processing may involve performing message validation with respect to the fourth message in one embodiment. Message validation may be performed in step  1365  based on authentication data accessed from the fourth message in one embodiment. For example, the first computer system (e.g.,  110 ) may generate second authentication data based on at least a portion of the fourth message (e.g., a header, a token, at least one option, a payload marker, a payload, etc.). The second authentication data may be compared to the authentication data (e.g., included in the fourth message) to verify the authenticity of the second computer system (e.g.,  120 ), verify the integrity of the fourth message, detect and/or act on a replay attack, some combination thereof, etc. 
     In one embodiment, the second authentication data may be generated in step  1365  using an authentication mechanism such as HMAC, OAuth, OAuth 2.0, OpenID, etc. The second authentication data may be generated in step  1365  using a key in one embodiment. For example, where the authentication mechanism used to generate the second authentication data in step  1365  is HMAC, the second authentication data may be generated by performing a hash function (e.g., MD5, SHA-1, SHA256, SHA512, etc.) on at least a portion of the fourth message (e.g., a header, a token, at least one option, a payload marker, a payload, some combination thereof, etc.) using a key. And in one embodiment, the fourth message may be free of the key used to generate the second authentication data in step  1365 . 
     An instance of the session key (e.g., accessed and/or stored in step  1330 , accessed in step  2260 , stored in step  2270 , etc.) may be used to generate the second authentication data in step  1365  in one embodiment. The instance of the session key may be stored locally at the first computer system (e.g.,  110 ) in one embodiment. For example, the instance of the session key may be stored locally in a security component (e.g.,  112  of computer system  110 ), in a memory (e.g., of computer system  110 ), in a database (e.g., of computer system  110 ), etc. Alternatively, the instance of the session key may be stored remotely (e.g., at another system or device) and accessed by the first computer system (e.g.,  110 ) in a secure manner in one embodiment. Accordingly, an instance of the session key may be securely accessed and used by the first computer system (e.g.,  110 ) to generate the second authentication data in step  1365  in one embodiment. 
     In one embodiment, step  1365  may be performed in accordance with one or more steps of process  2800 . In this case, the one or more steps of process  2800  may be performed at or by a caller system (e.g., the first computer system or computer system  110 ). 
     For example, the fourth message may be processed (e.g., in accordance with step  2810 ) in step  1365 . Message validation may be performed in step  1365  (e.g., in accordance with step  2820 ), where the message validation may be performed based on authentication data (e.g., included in the fourth message) in one embodiment. If the fourth message is determined to be valid (e.g., in accordance with step  2830 ), then at least one operation associated with the fourth message may be performed in step  1365  (e.g., in accordance with step  2840 ). Alternatively, if the fourth message is determined to be invalid (e.g., in accordance with step  2830 ), then at least one other operation associated with the fourth message may be performed in step  1365  (e.g., in accordance with step  2850 ). 
     As shown in  FIG. 13B , step  1370  involves increasing the security of communications between the first and second computer systems using the session key. In one embodiment, a respective instance of the session key may be used in step  1370  at each of the first and second computer systems to increase communication security. For example, an instance of the session key (e.g., accessed and/or stored in step  1330 , accessed in step  2260 , stored in step  2270 , etc.) may be used at the first computer system (e.g.,  110 ), whereas another instance of the session key (e.g., accessed and/or stored in step  1345 , accessed in step  2660 , stored in step  2665 , etc.) may be used at the second computer system (e.g.,  120 ). 
     In one embodiment, communication security may be increased in step  1370  by using at least one instance of the session key to generate authentication data and/or perform message validation based thereon. For example, the first computer system (e.g.,  110 ) may access and use an instance of the session key (e.g., accessed and/or stored in step  1330 , accessed in step  2260 , stored in step  2270 , etc.) to generate authentication data to be included in a message. Responsive to receiving the message, the second computer system (e.g.,  120 ) may use another instance of the session key (e.g., accessed and/or stored in step  1345 , accessed in step  2660 , stored in step  2665 , etc.) to perform message validation with respect to the message. In one embodiment, message validation may be performed (e.g., by the second computer system) with respect to the message by generating second authentication data, based on the message, using the another instance of the session key and determining if the second authentication data correlates to authentication data accessed from the message. In this manner, communication security may be increased by allowing the second computer system to verify the authenticity of the sender of the message (e.g., the first computer system), verify the integrity of the message, detect and/or act on a replay attack, some combination thereof, etc. 
     As another example, the second computer system (e.g.,  120 ) may access and use an instance of the session key (e.g., accessed and/or stored in step  1345 , accessed in step  2660 , stored in step  2665 , etc.) to generate authentication data to be included in a message. Responsive to receiving the message, the first computer system (e.g.,  110 ) may use another instance of the session key (e.g., accessed and/or stored in step  1330 , accessed in step  2260 , stored in step  2270 , etc.) to perform message validation with respect to the message. In one embodiment, message validation may be performed (e.g., by the first computer system) with respect to the message by generating second authentication data, based on the message, using the another instance of the session key and determining if the second authentication data correlates to authentication data accessed from the message. In this manner, communication security may be increased by allowing the first computer system to verify the authenticity of the sender of the message (e.g., the second computer system), verify the integrity of the message, detect and/or act on a replay attack, some combination thereof, etc. 
     Communication security may be increased in step  1370  by using at least one instance of the session key to encrypt and/or decrypt at least a respective portion of one or more messages communicated between the first and second computer systems in one embodiment. For example, at least a portion of a message generated by the first computer system (e.g.,  110 ) may be encrypted using the an instance of the session key (e.g., accessed and/or stored in step  1330 , accessed in step  2260 , stored in step  2270 , etc.), and responsive to receiving the message, the encrypted data may be decrypted by the second computer system (e.g.,  120 ) using another instance of the session key (e.g., accessed and/or stored in step  1345 , accessed in step  2660 , stored in step  2665 , etc.). As another example, at least a portion of a message generated by the second computer system (e.g.,  120 ) may be encrypted using the an instance of the session key (e.g., accessed and/or stored in step  1345 , accessed in step  2660 , stored in step  2665 , etc.), and responsive to receiving the message, the encrypted data may be decrypted by the first computer system (e.g.,  110 ) using another instance of the session key (e.g., accessed and/or stored in step  1330 , accessed in step  2260 , stored in step  2270 , etc.). In one embodiment, encryption and/or decryption in step  1370  of at least a respective portion of one or more messages communicated between the first and second computer systems may be performed using AES, Blowfish, RC4, the Extended Tiny Encryption Algorithm (XTEA) scheme, another symmetric-key algorithm, etc. 
     In one embodiment, at least a portion of a message encrypted and/or decrypted using the session key (or at least one instance thereof) in step  1370  may be the payload of the message. The portion of a message encrypted and/or decrypted using the session key (or at least one instance thereof) in step  1370  may include authentication data generated using the session key (or at least one instance thereof) in one embodiment. And in one embodiment, the portion of a message encrypted and/or decrypted using the session key (or at least one instance thereof) in step  1370  may be free of authentication data (e.g., generated using the session key or at least one instance thereof). 
     Step  1370  may involve communicating at least one message using DTLS in one embodiment. For example, where the at least one message is a CoAP message (e.g.,  200 ,  500 A,  500 B, etc.), step  1370  may involve communicating the at least one message over CoAP using DTLS. 
     Where the session key (or at least one instance thereof) is generated by and/or communicated from a third computer system (e.g.,  1430 ), the third computer system may be used to perform one or more operations on behalf of the second computer system (e.g.,  120 ). For example, the third computer system (e.g.,  1430 ) may determine whether the first computer system (e.g.,  110 ) is authorized to communicate with the second computer system (e.g.,  120 ), verify the authenticity of the first computer system (e.g.,  110 ), verify message integrity, detect and/or act on a replay attack, some combination thereof, etc. In this manner, the third computer system (e.g.,  1430 ) may act as an intermediary or broker to assist the second computer system (e.g.,  120 ), thereby increasing communication security. 
     In addition to increasing communication security, use of the third computer (e.g.,  1430 ) system can provide other benefits. For example, offloading operations to the third computer system (e.g.,  1430 ) can reduce the processing resources and/or storage resources utilized by the second computer system (e.g.,  120 ) for communication security. As another example, where the storage resources of the third computer system (e.g.,  1430 ) exceed the storage resources of the second computer system (e.g.,  120 ), use of the third computer system (e.g.,  1430 ) to store data (e.g., registration data, permissions data, permissions configuration data, at least one key, at least one secret key, at least one private key, at least one session key, at least one instance of at least one session key, some combination thereof, etc.) associated with the operations (e.g., offloaded to the third computer system) can allow the second computer system (e.g.,  120 ) to communicate with a larger number of computer systems or devices (e.g., including computer system  110 , at least one other computer system or device, etc.). 
     In one embodiment, step  1370  may be performed in accordance with one or more steps of process  3000  of  FIGS. 30A, 30B, and 30C .  FIGS. 30A, 30B, and 30C  show a flowchart of process  3000  for increasing communication security in accordance with one embodiment. In one embodiment, one or more steps of process  3000  may be performed during and/or define at least a portion of a session. 
     As shown in  FIG. 30A , step  3005  involves accessing message data. In one embodiment, step  3005  may be performed using a message generation component (e.g.,  114  of computer system  110 ,  124  of computer system  120 , etc.). 
     In one embodiment, the message data accessed in step  3005  may include data other than authentication data. For example, the message data may include data associated with a header (e.g., included in portion  210  of CoAP message  200 ), data associated with a token (e.g., included in portion  220  of CoAP message  200 ), data associated with at least one option (e.g., included in portion  230  of CoAP message  200 ), data associated with a payload marker (e.g., included in portion  240  of CoAP message  200 ), data associated with at least a portion of a payload (e.g., included in portion  250  of CoAP message  200 ), data other than the authentication data (e.g., “Authentication Data 1” of CoAP message  500 A, “Authentication Data 2” of CoAP message  500 B, etc.), some combination thereof, etc. 
     As shown in  FIG. 30A , step  3007  involves accessing a session key (or an instance thereof). In one embodiment, step  3007  may be performed using a security component (e.g.,  112  of computer system  110 ,  122  of computer system  120 , etc.). 
     For example, step  3007  may involve accessing an instance of a session key (e.g., accessed and/or stored in step  1330 , accessed in step  2260 , stored in step  2270 , etc.) at a caller system (e.g., the first computer system or computer system  110 ). Step  3007  may involve accessing an instance of the session key that is stored locally at a caller system (e.g., the first computer system or computer system  110 ) in one embodiment. For example, the instance of the session key may be accessed in step  3007  from a security component (e.g.,  112  of computer system  110 ), a memory (e.g., of computer system  110 ), a database (e.g., of computer system  110 ), etc. Alternatively, the instance of the session key may be remotely accessed by a caller system (e.g., the first computer system or computer system  110 ) in step  3007  from another system or device in one embodiment. 
     As another example, step  3007  may involve accessing an instance of a session key (e.g., accessed and/or stored in step  1345 , accessed in step  2660 , stored in step  2665 , etc.) at a target system (e.g., the second computer system or computer system  120 ). Step  3007  may involve accessing an instance of the session key that is stored locally at the target system in one embodiment. For example, the instance of the session key may be accessed in step  3007  from a security component (e.g.,  122  of computer system  120 ), a memory (e.g., of computer system  120 ), a database (e.g., of computer system  120 ), etc. Alternatively, the instance of the session key may be remotely accessed by the target system in step  3007  from another system or device in one embodiment. 
     As shown in  FIG. 30A , step  3010  involves generating authentication data using the session key (e.g., accessed in step  3007 ). In one embodiment, step  3010  may be performed using a security component (e.g.,  112  of computer system  110 ,  122  of computer system  120 , etc.). 
     In one embodiment, the authentication data may be generated in step  3010  using an authentication mechanism such as HMAC, OAuth, OAuth 2.0, OpenID, etc. Where the authentication mechanism used to generate the authentication data in step  3010  is HMAC, the authentication data may be generated by performing a hash function (e.g., MD5, SHA-1, SHA256, SHA512, etc.) on message data (e.g., accessed in step  3005 ) using the session key (e.g., accessed in step  3007 ). In one embodiment, the message data may be free of the session key (e.g., accessed in step  3007 ). 
     As shown in  FIG. 30A , step  3015  involves optionally generating encrypted data using the session key. Step  3015  may involve encrypting data to generate the encrypted data (e.g., as or including ciphertext). In one embodiment, the data encrypted in step  3015  may include at least a portion of the message data (e.g., accessed in step  3005 ), at least a portion of the authentication data (e.g., generated in step  3010 ), some combination thereof, etc. And in one embodiment, the encrypted data may be generated in step  3015  using AES, Blowfish, RC4, the Extended Tiny Encryption Algorithm (XTEA) scheme, another symmetric-key algorithm, etc. 
     Where the encrypted data includes authentication data, it should be appreciated that the encrypted authentication data (e.g., as ciphertext) may be generated by performing a plurality of operations using the session key (or an instance thereof). For example, the authentication data may be generated (e.g., in step  3010 ) using an instance of the session key, and the authentication data (e.g., alone, or with other data or content) may be encrypted (e.g., in step  3015 ) using the instance of the session key. 
     In one embodiment, the data encrypted in step  3015  may include data or content associated with a payload. For example, step  3015  may involve encrypting authentication data (e.g., “Authentication Data 1”) associated with and/or to be included in a payload of a message (e.g., CoAP message  500 A). As another example, step  3015  may involve encrypting authentication data (e.g., “Authentication Data 2”) and/or other data (e.g., the data or content of “22.5 C”) associated with and/or to be included in a payload of a message (e.g., CoAP message  500 B). 
     As shown in  FIG. 30A , step  3020  involves generating a message including the message data (e.g., accessed in step  3005 ) and the authentication data (e.g., generated in step  3010 ). In one embodiment, step  3020  may be performed using a message generation component (e.g.,  114  of computer system  110 ,  124  of computer system  120 , etc.). 
     In one embodiment, where the message generated in step  3020  is a CoAP message (e.g.,  500 A,  500 B, etc.), step  3020  may involve formatting the message data (e.g., accessed in step  3005 ) in accordance with CoAP (e.g., into one or more portions of CoAP message  200 ). The authentication data (e.g., generated in step  3010 ) may be included in or as the payload (e.g., associated with portion  250  of CoAP message  200 ) of the CoAP message in one embodiment. For example, as shown in  FIG. 5A , authentication data (e.g., “Authentication Data 1”) may be included in or as the payload of CoAP message  500 A. As another example, as shown in  FIG. 5B , authentication data (e.g., “Authentication Data 2”) may be included in or as the payload of CoAP message  500 B. 
     Step  3020  may involve including other data or content (e.g., accessed in step  3005  as at least part of the message data) in or as the payload of the message in one embodiment. For example, as shown in  FIG. 5B , other data or content (e.g., “22.5 C”) may be included in or as the payload of CoAP message  500 B in step  3020 . And in one embodiment, other data or content (e.g., accessed in step  3005  as at least part of the message data) may be included in or as another portion of the message in step  3020 . 
     Step  3020  may involve including encrypted data (e.g., generated in step  3015 ) in or as the payload of the message in one embodiment. For example, where encrypted data includes authentication data (e.g., “Authentication Data 1” as depicted in  FIG. 5A ), step  3020  may involve including the authentication data as encrypted data (e.g., as ciphertext) in or as the payload of the message (e.g., CoAP message  500 A). As another example, where encrypted data includes authentication data (e.g., “Authentication Data 2” as depicted in  FIG. 5B ) and other data or content (e.g., “22.5 C” as depicted in  FIG. 5B ), step  3020  may involve including the authentication data and the other data or content as encrypted data (e.g., as ciphertext) in or as the payload of the message (e.g., CoAP message  500 B). And in one embodiment, step  3020  may involve including encrypted data (e.g., generated in step  3015 ) in or as another portion of the message in step  3020 . 
     In one embodiment, step  3020  may involve generating a bit stream or byte stream including the message data (e.g., accessed in step  3005 ) and the authentication data (e.g., generated in step  3010 ). In one embodiment, step  3020  may involve generating a bit stream or byte stream including the encrypted data (e.g., generated in step  3015 ) and/or other data (e.g., at least a portion of the message data, at least a portion of the authentication data, etc.). The bit stream or byte stream may be formatted in accordance with CoAP in one embodiment. 
     As shown in  FIG. 30A , step  3030  involves communicating the message (e.g., generated in step  3020 ). Where the message is generated (e.g., in step  3020 ) at a caller system (e.g., the first computer system or computer system  110 ), step  3030  may involve communicating the message from the caller system to a target system (e.g., the second computer system or computer system  120 ). Alternatively, where the message is generated (e.g., in step  3020 ) at a target system (e.g., the second computer system or computer system  120 ), step  3030  may involve communicating the message from the target system to a caller system (e.g., the first computer system or computer system  110 ). 
     In one embodiment, the message may be communicated in step  3030  over a connection (e.g.,  130  between computer system  110  and computer system  120 ). The message may be communicated in step  3030  as a bit stream or a byte stream in one embodiment. And in one embodiment, step  3030  may involve communicating the message using at least one communication interface (e.g.,  118  of computer system  110 ,  128  of computer system  120 , etc.). 
     Step  3030  may involve communicating the message using Datagram Transport Layer Security (DTLS) in one embodiment. For example, where the message is a CoAP message (e.g.,  200 ,  500 A,  500 B, etc.), step  3030  may involve communicating the message over CoAP using DTLS. 
     As shown in  FIG. 30B , step  3040  involves receiving the message (e.g., communicated in step  3030 ). Where the message is communicated (e.g., in step  3030 ) from a caller system (e.g., the first computer system or computer system  110 ), step  3040  may involve receiving the message at a target system (e.g., the second computer system or computer system  120 ). Alternatively, where the message is communicated (e.g., in step  3030 ) from a target system (e.g., the second computer system or computer system  120 ), step  3040  may involve receiving the message at a caller system (e.g., the first computer system or computer system  110 ). 
     In one embodiment, the message may be received in step  3040  over a connection (e.g.,  130 ). The message may be received in step  3040  as a bit stream or a byte stream in one embodiment. And in one embodiment, step  3040  may involve receiving the message using a communication interface (e.g.,  118  of computer system  110 ,  128  of computer system  120 , etc.). 
     Step  3040  may involve receiving the message using Datagram Transport Layer Security (DTLS) in one embodiment. For example, where the message is a CoAP message (e.g.,  200 ,  500 A,  500 B, etc.), step  3040  may involve receiving the message over CoAP using DTLS. 
     As shown in  FIG. 30B , step  3042  involves accessing a session key (or an instance thereof). And in one embodiment, step  3042  may be performed using a security component (e.g.,  112  of computer system  110 ,  122  of computer system  120 , etc.). 
     Where the message is received at a caller system (e.g., the first computer system or computer system  110 ) in step  3040 , step  3042  may involve accessing an instance of a session key (e.g., accessed and/or stored in step  1330 , accessed in step  2260 , stored in step  2270 , etc.) at the caller system. Step  3042  may involve accessing an instance of the session key that is stored locally at a caller system (e.g., the first computer system or computer system  110 ) in one embodiment. For example, the instance of the session key may be accessed in step  3042  from a security component (e.g.,  112  of computer system  110 ), a memory (e.g., of computer system  110 ), a database (e.g., of computer system  110 ), etc. Alternatively, the instance of the session key may be remotely accessed by a caller system (e.g., the first computer system or computer system  110 ) in step  3042  from another system or device in one embodiment. 
     Where the message is received at a target system (e.g., the second computer system or computer system  120 ) in step  3040 , step  3042  may involve accessing an instance of a session key (e.g., accessed and/or stored in step  1345 , accessed in step  2660 , stored in step  2665 , etc.) at the target system. Step  3042  may involve accessing an instance of the session key that is stored locally at a target system (e.g., the second computer system or computer system  120 ) in one embodiment. For example, the instance of the session key may be accessed in step  3042  from a security component (e.g.,  122  of computer system  120 ), a memory (e.g., of computer system  120 ), a database (e.g., of computer system  120 ), etc. Alternatively, the instance of the session key may be remotely accessed by a target system (e.g., the second computer system or computer system  120 ) in step  3042  from another system or device in one embodiment. 
     In one embodiment, the session keys accessed in steps  3007  and  3042  may be different instances of the same session key. For example, the session keys accessed in steps  3007  and  3042  may be different instances of the same session key generated (e.g., at or by the third computer system or computer system  1430 ) in step  1320 , in step  2035 , etc. 
     As shown in  FIG. 30B , step  3044  involves optionally determining whether the session key (e.g., accessed in step  3042 ) is valid. In one embodiment, step  3044  may be performed using a security component (e.g.,  112  of computer system  110 ,  122  of computer system  120 , etc.). 
     In one embodiment, step  3044  may involve determining whether the session key (e.g., accessed in step  3042 ) is valid based on expiration data (e.g., accessed in step  2650 ). For example, the session key may be determined to be valid in step  3044  if the session key is not expired (e.g., as determined based on the expiration data). As another example, the session key may be determined to be invalid in step  3044  if the session key is expired (e.g., as determined based on the expiration data). If the session key is determined to be valid in step  3044 , then step  3046  may be performed. 
     As shown in  FIG. 30B , step  3046  involves optionally decrypting at least a portion of the message using the session key (e.g., accessed in step  3042 ). In one embodiment, where the message includes encrypted data (e.g., generated in step  3015 ), the at least a portion of the message decrypted in step  3046  may include the encrypted data. And in one embodiment, the at least a portion of the message may be decrypted in step  3046  using AES, Blowfish, RC4, the Extended Tiny Encryption Algorithm (XTEA) scheme, another symmetric-key algorithm, etc. And in one embodiment, step  3046  may be performed using a security component (e.g.,  112  of computer system  110 ,  122  of computer system  120 , etc.). 
     Step  3046  may involve decrypting at least a portion of the message (e.g., as ciphertext) to generate other data (e.g., as or including plaintext or unencrypted data) in one embodiment. The other data may include at least a portion of the message data (e.g., accessed in step  3005 ), at least a portion of the authentication data (e.g., generated in step  3010 ), the data used to generate the encrypted data (e.g., in step  3015 ), some combination thereof, etc. 
     The key used to decrypt at least a portion of the message (e.g., in step  3046 ) and the key used to generate encrypted data (e.g., in step  3015 ) may be different instances of the same session key (e.g., each stored at and/or accessible to a respective computer system) in one embodiment. In this manner, a symmetric-key algorithm may be used to secure data (e.g., used to generate the encrypted data in step  3015  and/or generated as a result of the decryption performed in step  3046 ) communicated using one or more messages. 
     As shown in  FIG. 30B , step  3048  involves optionally determining whether the decryption (e.g., performed in step  3046 ) is successful. In one embodiment, step  3048  may be performed using a security component (e.g.,  112  of computer system  110 ,  122  of computer system  120 , etc.). If the decryption (e.g., performed in step  3046 ) is determined to be successful in step  3048 , then step  3050  may be performed. 
     As shown in  FIG. 30C , step  3050  involves processing the message. In one embodiment, step  3050  may involve processing the message as received in step  3040 . In one embodiment, step  3050  may involve processing the message including other data generated as a result of decryption performed in step  3046 . And in one embodiment, the other data (e.g., generated as a result of decryption performed in step  3046 ) may be processed in step  3050  alone or in combination with at least one other portion of the message (e.g., in the format or state as received in step  3040 ). 
     Processing of the message in step  3050  may involve accessing authentication data from the message in one embodiment. In one embodiment, step  3050  may involve processing the message using a security component (e.g.,  112  of computer system  112 ,  122  of computer system  120 , etc.). And in one embodiment, where the message is a CoAP message, step  3050  may be performed in accordance with step  650  and/or one or more steps of process  900  of  FIG. 9 . 
     As shown in  FIG. 30C , Step  3060  involves performing message validation (e.g., with respect to the message received in step  3040 , processed in step  3050 , etc.). The message validation may be used to verify the authenticity of the sender of the message and/or the integrity of the message. Where the message includes a nonce, the message validation may be used to detect a replay attack. 
     In one embodiment, message validation may be performed in step  3060  based on authentication data (e.g., accessed from the message in step  3050 ). And in one embodiment, message validation may be performed in step  3060  using at least one message invalidity condition. 
     Where message validation is performed based on authentication data, message validation may be performed in step  3060  by comparing second authentication data to the authentication data in one embodiment. For example, the recipient of the message (e.g., computer system  110 , computer system  120 , etc.) may generate second authentication data based on at least a portion of the message (e.g., a header, a token, at least one option, a payload marker, a payload, some combination thereof, etc.). The second authentication data may be compared to the authentication data (e.g., included in the message and/or accessed in step  3050 ) to verify the authenticity of the sender of the message (e.g., computer system  110 , computer system  120 , etc.), verify the integrity of the message, detect and/or act on a replay attack, some combination thereof, etc. 
     In one embodiment, the second authentication data may be generated in step  3060  using an authentication mechanism such as HMAC, OAuth, OAuth 2.0, OpenID, etc. The second authentication data may be generated in step  3060  using a key in one embodiment. For example, where the authentication mechanism used to generate the second authentication data in step  3060  is HMAC, the second authentication data may be generated by performing a hash function (e.g., MD5, SHA-1, SHA256, SHA512, etc.) on at least a portion of the message (e.g., a header, a token, at least one option, a payload marker, a payload, some combination thereof, etc.) using a key. And in one embodiment, the message may be free of the key used to generate the second authentication data in step  3060 . 
     An instance of a session key may be used to generate the second authentication data in step  3060  in one embodiment. For example, where the message is received (e.g., in step  3040 ) at a caller system (e.g., the first computer system or computer system  110 ), an instance of a session key (e.g., accessed and/or stored in step  1330 , accessed in step  2260 , stored in step  2270 , etc.) may be used by the caller system to generate the second authentication data in step  3060 . The instance of the session key may be stored locally at the caller system in one embodiment. For example, the instance of the session key may be stored locally in a security component (e.g.,  112  of computer system  110 ), in a memory (e.g., of computer system  110 ), in a database (e.g., of computer system  110 ), etc. Alternatively, the instance of the session key may be stored remotely (e.g., at another system or device) and accessed by the caller system in a secure manner in one embodiment. Accordingly, an instance of a session key may be securely accessed and used by a caller system (e.g., the first computer system or computer system  110 ) to generate the second authentication data in step  3060  in one embodiment. 
     As another example, where the message is received (e.g., in step  3040 ) at a target system (e.g., the second computer system or computer system  120 ), an instance of a session key (e.g., accessed and/or stored in step  1345 , accessed in step  2660 , stored in step  2665 , etc.) may be used by the target system to generate the second authentication data in step  3060 . The instance of the session key may be stored locally at the target system in one embodiment. For example, the instance of the session key may be stored locally in a security component (e.g.,  122  of computer system  120 ), in a memory (e.g., of computer system  120 ), in a database (e.g., of computer system  120 ), etc. Alternatively, the instance of the session key may be stored remotely (e.g., at another system or device) and accessed by the target system in a secure manner in one embodiment. Accordingly, an instance of a session key may be securely accessed and used by a target system (e.g., the second computer system or computer system  120 ) to generate the second authentication data in step  3060  in one embodiment. 
     Where message validation is performed using at least one message invalidity condition, the message may be determined to be invalid in step  3060  if any of the at least one message invalidity condition is triggered in one embodiment. For example, the message may be determined to be invalid in step  3060  responsive to a failure to access a unique identifier associated with the sender of the message. As another example, the message may be determined to be invalid in step  3060  responsive to a failure to access a nonce from the message. As a further example, the message may be determined to be invalid in step  3060  responsive to determining that a nonce accessed from the message is not different from another nonce accessed from a previous message. As yet another example, the message may be determined to be invalid in step  3060  responsive to determining that a payload of the message is not at least a predetermined size. And as another example, the message may be determined to be invalid in step  3060  responsive to a failure to access a key (e.g., an instance of the session key) used to generate the second authentication data or otherwise perform the message validation. 
     The message validation may be performed in step  3060  using a security component (e.g.,  112  of computer system  110 ,  122  of computer system  120 , etc.) in one embodiment. And in one embodiment, where the message is a CoAP message, step  3060  may be performed in accordance with step  660 , one or more steps of process  1000  of  FIG. 10 , one or more steps of process  1100  of  FIG. 11 , some combination thereof, etc. 
     As shown in  FIG. 30C , step  3070  involves determining whether the message (e.g., received in step  3040 , processed in step  3050 , etc.) is valid (e.g., based on the results of the message validation performed in step  3060 ). Step  3070  may be performed using a security component (e.g.,  112  of computer system  110 ,  122  of computer system  120 , etc.) in one embodiment. If it is determined in step  3070  that the message is valid, then step  3080  may be performed. 
     Step  3080  involves performing at least one operation associated with the message (e.g., received in step  3040 , processed in step  3050 , etc.). In one embodiment, step  3080  may involve performing at least one operation using an operation component (e.g.,  116  of computer system  110 ,  126  of computer system  120 , etc.). 
     In one embodiment, the at least one operation performed in step  3080  may include at least one operation associated with a request of the message. For example, where the message is associated with a request to obtain data or content (e.g., a temperature, a voltage, etc.), the at least one operation may involve accessing the requested data or content. 
     The at least one operation performed in step  3080  may include communication of another message in one embodiment. For example, responsive to determining that the message is valid (e.g., in step  3070 ), another message may be communicated in step  3080  from the recipient of the message. Another message may be communicated in step  3080  to the sender of the message (e.g., received in step  3040 , processed in step  3050 , etc.), to another computer system or device, etc. In one embodiment, where another message is generated and/or communicated in step  3080 , step  3080  may involve repeating or otherwise performing one or more steps of process  3000 . 
     In one embodiment, the at least one operation performed in step  3080  may include at least one operation associated with a response of the message. For example, where the message is associated with a response including data or content, the at least one operation may include processing the data or content, performing one or more other operations with respect to the data or content, etc. 
     Step  3080  may be performed in accordance with step  2840  of process  2800  in one embodiment. And in one embodiment, where the message (e.g., received in step  3040 , processed in step  3050 , etc.) is a CoAP message, step  3080  may be performed in accordance with step  680  of process  600 . 
     Alternatively, if it is determined in step  3070  that the message (e.g., received in step  3040 , processed in step  3050 , etc.) is not valid, then at least one other operation associated with the message may be performed in step  3090 . In one embodiment, step  3090  may involve performing at least one operation using an operation component (e.g.,  116  of computer system  110 ,  126  of computer system  120 , etc.). 
     In one embodiment, step  3090  may involve acting responsive to a message validation failure such as a triggering of a message invalidity condition (e.g., corresponding to one or more steps of process  1100 , a failure to access a unique identifier associated with the sender of the message, a failure to access a nonce from the message, determining that a nonce accessed from the message is not different from another nonce accessed from a previous message, determining that a payload of the message is not at least a predetermined size, a failure to access a key used to generate the second authentication data or otherwise perform the message validation, some combination thereof, etc.), another message validation failure (e.g., determining that the second authentication data generated based on at least a portion of the message does not correlate to authentication data accessed from the message, another message validation failure, etc.), etc. And in one embodiment, step  3090  may involve acting on a suspected or detected replay attack. 
     The at least one other operation performed in step  3090  may include ignoring the message (e.g., received in step  3040 , processed in step  3050 , etc.) in one embodiment. For example, another message may not be generated and/or communicated in reply to the message (e.g., received in step  3040 , processed in step  3050 , etc.) in step  3090 . As another example, no further processing related to the message (e.g., received in step  3040 , processed in step  3050 , etc.) may be performed in step  3090 . And in one embodiment, the at least one other operation performed in step  3090  may include limiting access to the recipient (e.g., of the message received in step  3040 ) of the sender (e.g., of the message communicated in step  3030 ). 
     In one embodiment, one or more steps of process  3000  may be repeated with respect to at least one other message. For example, where a message is generated and communicated (e.g., in accordance with one or more steps of process  3000 ), at least one other message may be generated and/or communicated (e.g., in accordance with one or more steps of process  3000 ). In one embodiment, the message may be associated with a request, and the at least one other message may be associated with at least one response (e.g., related to the request of the message). 
     Although  FIG. 30  depicts process  3000  as including a specific number of steps, it should be appreciated that process  3000  may include a different number of steps in other embodiments. Although  FIG. 30  depicts process  3000  as including a specific ordering of steps, it should be appreciated that process  3000  may include a different ordering of steps in other embodiments. 
     Although  FIG. 14  shows system  1400  with a specific number and type of systems or devices, it should be appreciated that system  1400  may include a different number and/or type of systems or devices in other embodiments. For example, system  1400  may include more than one instance of computer system  110  and/or computer system  120  in one or more other embodiments. Where system  1400  includes more than one instance of computer system  110 , each instance of computer system  110  may communicate with computer system  120  over a respective connection (e.g., similar to connection  130 ). Where system  1400  includes more than one instance of computer system  120 , each instance of computer system  120  may communicate with computer system  110  over a respective connection (e.g., similar to connection  130 ). As such, embodiments can increase the security associated with communication of messages between any number of systems or devices. 
     Although  FIGS. 13A and 13B  depict process  1300  as including a specific number of steps, it should be appreciated that process  1300  may include a different number of steps in other embodiments. Although  FIGS. 13A and 13B  depict process  1300  as including a specific ordering of steps, it should be appreciated that process  1300  may include a different ordering of steps in other embodiments. 
     In the foregoing specification, embodiments have been described with reference to numerous specific details that may vary from implementation to implementation. Thus, the sole and exclusive indicator of what is, and is intended by the applicant to be, the invention is the set of claims that issue from this application, in the specific form in which such claims issue, including any subsequent correction thereto. Hence, no limitation, element, property, feature, advantage, or attribute that is not expressly recited in a claim should limit the scope of such claim in any way. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.