Patent Publication Number: US-8543684-B2

Title: Method for computing the entropic value of a dynamical memory system

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation-in-Part of U.S. patent application Ser. No. 12/120,075, filed on May 13, 2008, and also claims the benefit of U.S. Provisional Application No. 60/968,009, filed Aug. 24, 2007, the entire disclosures of which are hereby incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to access control systems, devices, and methods. More specifically, the present invention is directed toward the dissemination of information in an access control system having at least one non-networked reader. 
     BACKGROUND 
     Control access systems have historically been completely interconnected by wired and/or wireless connections. More specifically, readers and other types of message hosts are generally in communication with a centralized control system such as a centralized control panel. The interconnectedness of the system allows policy updates to be quickly and efficiently disseminated throughout the access control system. If a policy update (e.g., sending new access permissions to all readers) is necessary, then the centralized control panel would send a message to the networked message hosts notifying them of the new policy. 
     While these completely interconnected systems help to facilitate efficient policy updates they are expensive to install and maintain, especially in large facilities where a significant amount of wire and/or wireless communication devices are required to have each message host in communication with the centralized control panel. Thus, non-networked message hosts (i.e., message hosts which are not in communication with a centralized control system via a direct communication path or message hosts that have a communication path that becomes unavailable), which are also referred to as local hosts, are becoming more desirable due to their autonomy and the low cost associated with their installation and maintenance. The downside to installing non-networked message hosts is that it becomes more difficult to ensure that the non-networked message host receives policy updates. 
     SUMMARY 
     Colonies in control access systems lacking long range or direct communication between message hosts can propagate messages between message hosts by means of an intermediary message carrier. Message hosts are typically stationary objects, such as an access control reader. Message carriers are typically mobile objects, such as an access control token. A message object contains data or information, such as access control policies, that can be understood and used by the message hosts. Message objects can originate at one or more message hosts and can be used by message hosts to perform an action, such as grant access to a secure area. A message object can be introduced utilizing one or more existing members from any colony or can be newly introduced colony members. In a system containing a colony of message hosts and a colony of message carriers, the message carriers can transport a message from one message host to another, thereby propagation the message object among the colony of message hosts. 
     A message originating on one or more message hosts can be conveyed from the message host to a message carrier when the message host and message carrier are in close proximity to each other. If a second message carrier is subsequently put in close proximity to a message host originating a message object, the message object can be conveyed from the message host to the second message carrier. A message carrier, after gaining knowledge of the message object, can transport the message object from a message host with knowledge of the message object, such as a message host that originates a message object, to a second message host with no knowledge of the message object and then convey the message object from the message carrier to the second message host when the message carrier is in close proximity to the second message host. After the message object is conveyed to the second message host, the second message host has knowledge of the message object. 
     Two colony systems are used, for example, in disconnected access control models. Such systems provide a simple and elegant solution for access control without the need to connect readers to a wired network. These systems provide a secure and elegant solution to access control when cost or installation of a wired network is undesirable. While these systems have been in use for more than twenty years, the optimization of these systems has not yet been achieved. 
     It is therefore one aspect of the present invention to improve on the current state of the art by providing a useful, concrete, and tangible result that can be used to understand and design optimal communication in two colony systems. This program can be applied more generally to the understanding and optimization of such two colony systems that rely on message carriers to deliver message objects to non-networked message hosts. 
     Embodiments of the present invention define a metric that provides a measure of information dissemination performance in a system having message hosts that can communicate with each other using a message carrier as an intermediary. Exemplary systems of the type described here are mail delivery where a message, in the form of a letter, is carried from one location to another or, in nature, a colony of bees that carry pollen from one plant to another. What these systems have in common is that a network is formed by the message carriers. The network is comprised of transient and asymmetrical connections between the hosts. A high performance system is defined here as one that is capable of efficient delivery of a message by the message carriers and distributed among the hosts. At least one embodiment of the present invention provides a method of measuring information dissemination efficiency in these systems and, when possible, to improve that efficiency. 
     Small World networks are characterized by localized networks that are connected to each other by critical links that provide a shortcut between otherwise distant or unconnected clusters. One popular example is the Kevin Bacon game where the goal is to find a path between any movie actor and Kevin Bacon using appearances in the same movies as connections. Connections between local clusters (movies) are made by an actor that appears in both movies. 
     An important difference between the actor network in the Kevin Bacon game and a network defined by message hosts and message carriers in an access control system is that a connection made by two actors appearing in the same movie is permanent and bidirectional, while the connection between two message hosts in our system is a transient and unidirectional event. This difference requires a slightly different tactic than the one typically used to study Small World networks. Rather than treating the message carrier population as vertices and the message hosts as edges, or the other way around, two distinct populations are both treated as vertices while the conveyance of a message object between these populations is treated as an edge. 
     This difference requires modifications to many of the standard graph-theory tools used to study networks. For example, if treated like a standard network, a degree distribution would be defined using the connections from message host-to-host; but in accordance with at least some embodiments of the present invention, the degree distribution will describe connections from message host-to-carrier and message carrier-to-host. 
     Related to the degree distribution, an adjacency matrix will not be a square n×n lattice but will have dimensions with the number of message carriers on one side and the number of message hosts on the other. Because each event is effectively a half-step in the process of sharing a message object between two like components, the traditional adjacency matrix can be found by squaring the matrix of the two vertex system. 
     Another consequence of the transient connection is that the connection defined in an adjacency matrix must be replaced with a probability weight representing connection strength to create a weighted adjacency matrix. A Markov Chain Monte Carlo based on a modeled weighted adjacency matrix can be used to simulate the propagation of message objects in the two-colony system. The message-carrier-to-message-host weighted adjacency matrix, W, is the engine that describes the information flow in this two colony network. 
     In one embodiment, a method is provided, the method generally comprising: 
     receiving message host information; 
     receiving message carrier information, wherein message carriers are operable to carry message objects between message hosts; 
     analyzing, with a network analysis module, the message host and message carrier information to determine at least one of (i) an amount of time required for a first message object to be communicated to a predetermined number of message hosts and/or a predetermined number of message carriers and (ii) a number of message hosts and/or message carriers that will receive the first message object within a predetermined amount of time; and 
     providing, with the network analysis module, an output to a user indicating results of the analyzing step. 
     It is one objective of the present invention to provide a secure access control system capable of working with non-networked message hosts (i.e., readers which contain no wired connection to a centralized database and operate quasi autonomously). 
     A Markov Chain Monte Carlo model may be used to examine the performance of a colony of message carriers to distribute message objects among a colony of message hosts. A performance measure may be defined to estimate the chance that an update will not reach its target before it is needed. 
     Disconnected access control networks may be modeled as two separate but interdependent populations, message carriers and message hosts. The interdependence is created because each population can only receive information from the other population when there is no direct message carrier-to-message carrier or door-to-door events, resulting in coupled partial differential equation. 
     Relationships found in disconnected networks may include a scaling for the total number of connections that follows the geometric mean of the number of message carriers and message hosts. In accordance with at least some embodiments of the present invention, connection strengths between message carriers and message hosts follow a Zipf-Mandelbrot distribution with a power of 2. 
     Security entropy of the system can be defined as a measure of the state-of-order for the system, for example it might be defined as the probability that an update will miss its target given a time dependent system state. The security entropy can be calculated and compared to sampled access control data and can be used to measure the security value against a system performance benchmark. Security entropy of a completely connected system would be zero, indicating that the system is fully updated. Disconnected or partially connected systems will have a security entropy that can be greater than zero. Remedies to reduce the security entropy and thereby improve system performance can also be proposed. Such proposals may include suggestions to alter a proposed configuration of message hosts (e.g., by altering the number, location, and/or network communication capabilities of the hosts) and message carriers (e.g., by altering the number, type, and permissions of carriers). 
     The Summary is neither intended or should it be construed as being representative of the full extent and scope of the present invention. The present invention is set forth in various levels of detail and the Summary as well as in the attached drawings and in the detailed description of the invention and no limitation as to the scope of the present invention is intended by either the inclusion or non inclusion of elements, components, etc. in the Summary. Additional aspects of the present invention will become more readily apparent from the detailed description, particularly when taken together with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  depicts a secured premises in accordance with embodiments of the prior art; 
         FIG. 2  depicts an access control system in accordance with embodiments of the present invention; 
         FIG. 3  depicts components of a reader in accordance with embodiments of the present invention; 
         FIG. 4  depicts a data structure used to organize communication histories and policy information in accordance with embodiments of the present invention; 
         FIG. 5  depicts components of a credential in accordance with embodiments of the present invention; 
         FIG. 6  depicts a network analysis tool used to optimize information dissemination in the access control system in accordance with embodiments of the present invention; 
         FIG. 7  is a flow chart depicting a method of optimizing a network configuration with respect to information dissemination in accordance with embodiments of the present invention; 
         FIG. 8  is a flow chart depicting a method of determining information dissemination information in accordance with embodiments of the present invention; 
         FIG. 9  is a flow chart depicting a method of optimizing information dissemination in a fixed network configuration in accordance with embodiments of the present invention; 
         FIG. 10  is a chart illustrating a degree distribution of connections with members in accordance with embodiments of the present invention; and 
         FIG. 11  is a chart illustrating message propagation through the access control system as a function of time in accordance with embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The invention will be illustrated below in conjunction with an exemplary access control system. Although well suited for use with, e.g., a system using access control readers and/or credentials, the invention is not limited to use with any particular type of access control system or configuration of system elements. Those skilled in the art will recognize that the disclosed techniques may be used in any data messaging application in which it is desirable to optimize information dissemination throughout the network. 
     The exemplary systems and methods of this invention will also be described in relation to analysis software, modules, and associated analysis hardware. However, to avoid unnecessarily obscuring the present invention, the following description omits well-known structures, components and devices that may be shown in block diagram form, are well known, or are otherwise summarized. 
     For purposes of explanation, numerous details are set forth in order to provide a thorough understanding of the present invention. It should be appreciated, however, that the present invention may be practiced in a variety of ways beyond the specific details set forth herein. 
     Embodiments of the present invention are generally directed toward devices and methods of using such devices in a secure access system. Although well suited for use in systems and methods employing RF communication protocols, embodiments of the present invention may be suitable for use in systems employing other communication protocols including, but not limited to, optical communication protocols, magnetic communication protocols, chemical messaging, and the like. 
     Referring initially to  FIG. 1 , a secured premises  100  will be described in accordance with at least some embodiments of the present invention. The secured premises  100  displayed may correspond to an actual premises having access control equipment. Alternatively, the secured premises  100  may be simulated and the depicted location of the equipment may correspond to possible locations. For example, the premises may be displayed on a user interface of a computing station such as a personal computer, laptop, or the like and each of the pieces of access control equipment may represent actual equipment that may be used on a real premises. 
     In accordance with at least one embodiment of the present invention, the secured premises  100  may comprise a plurality of access points  104  each having a message host associated therewith. The access points  104  may comprise points of access to the interior of the premises  100 . Alternatively, the access points  104  may comprise points of access to rooms within the premises  100 . 
     In the depicted embodiment, message hosts correspond to access control readers  108 . In addition to access points  104 , the premises  100  may comprise one or more assets  106 . Examples of assets  106  may include secured computing resources (e.g., databases, computers, laptops, servers, etc.), financial resources (e.g., bank accounts, credit accounts, financial information, etc.), physical resources (e.g., office equipment, safes, files, etc.). 
     The assets  106  may also comprise a corresponding message host to control/restrict/monitor access to the asset  106 . In accordance with at least some embodiments of the present invention, the readers  108  may be used to control a user&#39;s access through an associated access point  104  or to an associated asset  106 . A user may be issued a credential  112 , which can be presented to a reader  108  when a user desires access through an access point  104  or to an asset  106 . The credentials  112  may comprise authentication information that can be wirelessly communicated to the readers  108  for verification of the user&#39;s access permissions. When a reader  108  verifies that a valid credential  112  has been presented thereto, the reader  108  may then permit the user access to the associated access point  104  and/or asset  106 . In accordance with at least one embodiment of the present invention access control decision may be made on the credentials  112  rather than the readers  108 . Further details of such an embodiment where decisions can be made on the credential  112  are described in U.S. patent application Ser. No. 11/778,145, entitled “Method and Apparatus for Making a Decision on a Card,” the entire contents of which are hereby incorporated herein by this reference. 
     In addition to carrying a user&#39;s validation information, the credentials  112  may be used as message carriers to carry message objects to the message hosts (i.e., readers  108 ). Exemplary credentials  112  may include, without limitation, Radio Frequency (RF) proximity cards, RF smart cards, magstripe cards, optically based access credentials, biometric authentication credentials, key fobs, CD-ROMS, flash drives, and any other portable medium capable of storing a message object and communicating the message object to a message host. In accordance with at least some embodiments of the present invention, at least some of the message hosts (i.e., readers  108 ) in the premises are non-networked, meaning that they have no direct mechanism of communication with any other message host. Instead, such non-networked message hosts rely on the message carriers to receive a message object and share message objects with other non-networked message hosts. 
       FIG. 2  depicts further details of a secure access system  200  in accordance with at least some embodiments of the present invention. The secure access system  200  generally includes a population of message hosts, typically in the form of access control readers. The population of message hosts may be divided into two types, namely networked message hosts  204  and non-networked message hosts  208 . Networked message hosts  204  comprise the ability to directly communicate with at least one other access control device, such as another networked message host  204  or a server  212 . The direct connection between the networked message hosts  204  and the other access control devices may be facilitated by a network connection  216 . The network connection  216  may be in the form of a wired and/or wireless communication link. 
     Due to their direct connectivity to other access control devices, the networked message hosts  204  may share message objects with one another without requiring an intermediary message carrier  220 . The server  212  may comprise a permissions server or some other type of centralized control panel that distributes message objects, such as access control policy information, to other networked message hosts  204 . In accordance with at least one embodiment of the present invention, the networked message hosts  204  may be used as access control devices that originate message objects throughout the secure access system  200 . The networked message hosts  204  may originally receive message objects from the server  212  via the network connection  216 . Then, when a message carrier  220 , such as a credential  112 , comes within communication range of the networked message host  204 , the networked message host  204  may communicate the message object to the message carrier  220 . The message carrier  220  may then store the message object and convey the message object to any other message host that it communicates with. In this way, the message carrier  220  can be used to carry a message object from a networked message host  204  to a non-networked message host  208 . 
     In accordance with at least one embodiment of the present invention, the message carrier  220  comprises an RF enabled credential and the message hosts  204 ,  208  comprise RF enabled readers. When the message carrier  220  is brought within a predefined communication range of the message host  204 ,  208 , an RF dialog may be established between the message host  204 ,  208  and message carrier  220 . During this communication dialog, the message host  204 ,  208  may communicate any type of active or most current message objects to the message carrier  220 . The message carrier  220  may, in a likewise fashion, communicate any type of active or most current message objects is has stored on its memory to the message host  204 ,  208 . This allows the message carrier  220  to supply new message objects to the message host  204 ,  208  and receive new message objects from the message host  204 ,  208 . The message carrier  220  can, therefore, be used as a mechanism for the non-networked message hosts  208  to share any message objects they have with other devices in the secure access system  200 . 
     In accordance with at least some embodiments of the present invention, message carriers  220  may only be allowed to send and/or receive message objects to/from message hosts  204 ,  208  after the message carrier  220  has been authenticated by the message host  204 ,  208  and the message host  204 ,  208  has determined that the message carrier  220  currently has permission to access the access point  104  or asset  106  associated with the message host  204 ,  208 . This is particularly useful to help deter the transmission of bad or otherwise unauthorized message objects throughout the secure access system  200 . The message hosts  204 ,  208  may restrict accepting a message object from a message carrier  220  until it has authenticated the message carrier and determined that its access permissions are valid. Additionally, the message hosts  204 ,  208  may refrain from sending a message object to message carriers  220  until there has been a proper authentication and validation of the message carrier  220 . 
     Referring now to  FIG. 3 , details of a reader  108  or similar type of message host  204 ,  208  will be described in accordance with at least some embodiments of the present invention. The reader  108  generally comprises the capability to automatically read data, typically in the form of a message object and/or validation information, from a credential  112 . The reader  108  may also be capable of writing data, typically in the form of a message object, back to the credential  112 . 
     The reader  108 , in accordance with at least one embodiment, comprises a credential communication interface  304  used to communicate back and forth with the credential  112 . The credential communication interface  304  may comprise an RF communication interface (e.g., an RF antenna), a magnetic communication interface (e.g., a magnetic stripe reader), an optical communication interface (e.g., an infrared detector and transmitter), an electrical contact communication interface, or any other means of communicating information to/from a credential  112 . 
     Connected to the communication interface  304  is a controller  308 . In one embodiment, the controller  308  includes a microprocessor, a random number generator, and a cryptographic coprocessor. The controller  308  is capable of properly modulating/demodulating data sent to and received from external devices such as the credential  112 . The controller  308  controls and determines how the reader  108  behaves when a credential  112  is presented to it. The controller  308  may include any general-purpose programmable processor, digital signal processor (DSP) or controller for executing application programming. Alternatively, the controller  308  may comprise a specially configured Application Specific Integrated Circuit (ASIC). 
     The controller  308  may also be provided with control circuitry capable of manipulating an access control device. The access control device is designed to secure the point of access  104  or asset  106  being protected by the reader  108 . The controller  308  is enabled to communicate with the access control device via the access control device interface  332 . Examples of a typical access control device include, without limitation, an electronic lock, a magnetic lock, or an electric strike for a door, a lock for a computer system, a lock for a database, a lock on a financial account, or a lock on a computer application. In one embodiment, the controller  308  actuates the access control device by sending a signal to the access control device via the access control device interface  332  based on results of an access decision made by the controller  308 . Optionally, the access control device may be integral to the reader  108  in one embodiment, in which case an access control device interface  332  would not be necessary. In an alternative embodiment, an access control device is external to the reader  108 , thus necessitating the interface  332 . Examples of an access control device interface  332  include any type of data port such as a USB port, serial data port, parallel data port, a convention wire, a wireless communication port such as a Bluetooth data interface, or any other type of wired or wireless communication interface. 
     In addition to an access control device interface  332 , the reader  108  may further comprise a memory  312 . The memory  312  may be used to store application data, the host unique ID, a communications history log  316 , a set of access policies  320  or other types of message objects, and any other functions that can be executed by the controller  308 . The memory  312  may comprise volatile and/or non-volatile memory. Examples of non-volatile memory include Read Only Memory (ROM), Erasable Programmable ROM (EPROM), Electronically Erasable PROM (EEPROM), Flash memory, and the like. Examples of volatile memory include Random Access Memory (RAM), Dynamic RAM (DRAM), Static RAM (SRAM), or buffer memory. In one embodiment, the memory  312  and the controller  308  are designed to utilize known security features to prevent unauthorized access to the contents of the memory  312  such as side channel analysis and the like. 
     The communication history log  316  may provide a location in memory where a register of all communications for the reader  108  is stored. The communication history log  316  may be used in connection with determining what credentials  112  are typically presented to a particular reader  108  as well as when and with what frequency such credentials  112  are presented to the reader  108 . Thus, the communication history log  316  may serve as a mechanism to model the information flow in a particular secure access system  200 . 
     The reader  108  may further comprise a clock  324 . The clock  324  is depicted as internal to the reader  108 , but the clock may also be external to the reader  108 . The clock  324  tracks the current time. The controller  308  may be adapted to read the time from the clock  324  and provide that time to a credential  112 , for the credential&#39;s communication history log. The clock  324  may further be employed to determine if the holder of a particular credential  112  is currently allowed access to an asset protected by the access control device  312 . The controller  308  may also reference the policies  320  in memory  312  to determine if a credential  112  is allowed access to an associated access point  104  or asset  106  based on the current time as determined by the clock  324 . The controller  308  may also reference the clock  324  to determine when a particular policy  320  should be implemented, in the event that one or more policies  320  is set to have a delayed start and comprises a timer mechanism. 
     A power source  328  may also be included in the reader  108  to provide power to the various devices contained within the reader  108 . The power source  328  may comprise internal batteries and/or an AC-DC converter such as a switch mode power supply or voltage regulator connected to an external AC power source. 
     Although not depicted, a reader  108  may further include a communication interface that provides communication capabilities between the reader  108  and external servers or other network nodes. Such a communication interface may include a USB port, a modem, a network adapter such as an Ethernet card, or any other communication adapter known in the art. These types of communication interfaces are typically only included in networked message hosts  204 . 
     Referring now to  FIG. 4 , additional details of the communication history log  316  will be described in accordance with at least some embodiments of the present invention. The communication history log  316  may comprise a number of different data fields, such as, a credential ID field  404 , a read time field  408 , a message object indicator field  412 , a message object details filed  416 , and a timer mechanism field  420 . The communication history log  316  may be used to store communications history for an associated reader  108 . The communications history  316  may be refreshed on a periodic (e.g., daily, weekly, monthly, yearly) basis. Alternatively, the communications history  316  may be maintained for the life of the reader  108 , in which case additional memory capacity may need to be added to the reader  108  during the course of its life. 
     The credential ID field  404  may comprise identification information for each credential  112  presented to the reader  108 . The information in the credential ID field  404  may include a unique card number assigned to the credential  112 , a user&#39;s name associated with the credential  112 , or some other information that uniquely identifies the credential  112 . Non-unique information may also be maintained in the credential ID field  404  such as site codes or other information that identifies a group to which the credential  112  belongs. 
     The read time field  408  may comprise information relating to the time when a particular credential  112  communicated with the reader  108 . The value in the read time field  408  may be obtained by referencing the clock  324 . The read time may be maintained to any type of granularity (e.g., months, weeks, days, hours, seconds, etc.), depending upon the required accuracy of read time. If no accurate read time is required, then the read time field  408  may simply provide an indication of the sequence in which a particular credential  112  was read relative to another credential  112 . 
     The message object indicator field  412  may contain information showing whether a particular credential  112  sent a policy or similar type of message object to the reader  108  and/or whether the reader sent a policy or similar type of message object to the credential  112 . The message object indicator field  412  may also provide identification information for certain message objects. More specifically, message objects may be circulated throughout the secure access system  200  with a particular name or identifier. When the message object is received by a new access control device, the message object identifier may be maintained in the message object indicator field  412  so that a reader  108  has a quick reference record of the message objects which it has received. Additionally, message object indicators may be provided for message objects which are transmitted to credentials  112 . This allows a system administrator to determine which credentials  112  have a particular message object stored thereon, without actually checking the credential  112  itself. 
     The message object details field  416  may contain details about the policy or message object which was transmitted to/from the reader  108 . In accordance with at least one embodiment of the present invention, when a message object corresponds to a new access control policy, the message object details field  416  incorporates a definition of the access control update. Such access control updates generally include a change in access rights for at least one credential  112  to access at least one point of access  104  or asset  106  associated with reader  108 . For example, if access permissions for a particular credential  112  have been revoked (e.g., because a user associated with the credential  112  no longer works for a company maintaining the premises  100 ), then the message object details field  416  may incorporate instructions telling all readers  108  to stop allowing the identified credential  112  access to associated access points  104  and/or assets  106 . Thus, information maintained in the message object details field  416  (and message objects in general) typically includes an identification of at least one credential  112  and an access rule for that at least one credential  112 . Alternatively, the message object may correspond to an application update for one or more applications stored on the reader  108 , in which case the message object details field  416  may comprise the updated application as well as instructions for the reader  108  to install the new application. Another type of message object used in accordance with at least some embodiments of the present invention may include a reader enable update. In this particular embodiment, the readers  108  may be adapted to stop allowing access to any credential  112  after a predetermined amount of time unless the reader receives a new message object renewing the reader&#39;s  108  activity subscription. 
     The message object, in addition to providing instructions for the reader  108  (or credential  112  in some applications) may also include a timer mechanism  420 . The timer mechanism  420  may define a life span for a particular message object. The information in the timer mechanism field  420  may include details related to the life span of the message object. More specifically, the timer mechanism  420  associated with a particular message object may cause the message object to become active only after a predetermined time. In other words, a delayed policy update may be implemented with message objects having timer mechanism  420  that define a certain time after the message object was first distributed before the message object becomes active (i.e., the timer mechanism may define a predetermined time in which a reader  108  should begin implementing the instructions contained within the message object). The timer mechanism  420  may also define how long a particular message object is to remain active. This particular implementation may utilize the timer mechanism to deactivate the message object after a predetermined amount of time, unless a new message object is received extending the timer mechanism. Accordingly, information in the timer mechanism field  420  may be used to define the beginning and end of an associated message object&#39;s lifetime. In accordance with at least some embodiments of the present invention, the timer mechanism may be appended to a message object at the beginning/end of the message object details or in a header of the message object. A flag may also be included in communications that contain a message object if the message object contains a timer mechanism  420 . Such a flag will allow the receiving access control device to search the message object for the relevant timer mechanism. 
       FIG. 5  depicts an exemplary credential  112  which will now be described in accordance with at least some embodiments of the present invention. The credential  112  may include a communication interface  504  that allows the credential  112  to communicate with external devices such as the reader  108 . The communication interface  504  may comprise an RF antenna that allows the credential  112  to receive and transmit data without contact. In other embodiments a magnetic, optical, or electrical contact communication interface  504  may be utilized. 
     A controller  508  may be connected to the communication interface  504 . The controller  504 , in one embodiment, includes a microprocessor, a random number generator, and a cryptographic coprocessor. The controller  508  may include any general-purpose programmable processor, digital signal processor (DSP) or controller for executing application programming. Alternatively, the controller  508  may comprise a specially configured application specific integrated circuit (ASIC). Similar to the controller  308  on the reader  108 , the controller  508  includes known security features that substantially prevent unauthorized access to the contents of memory  512 . 
     The memory  512  typically comprises non-volatile memory, such as flash memory. Non-volatile memory is generally used because the credential  112  is preferably a passive credential meaning that it does not have an internal source of power. Rather, the credential  112  uses energy from an RF field created by the reader  108  to power its components. Contents of the memory  512  may include a communication history log  516 , policies  520  and other message objects, and any other applications to be executed by the credential  112 . The communication history log  516  is similar to the communication history log  316  stored on the reader  108  except the credential ID field  404  is replaced with a reader ID field, where the reader ID field identifies reader with which the credential  112  has communicated with. More particularly, the reader ID field identifies readers  108  to which the credential  112  has transmitted message objects and readers  108  from which the credential  112  has received message objects. 
     In an alternative embodiment the credential  112  may be provided with an onboard power supply. Such credentials  112  are known as active credentials  112 . An active credential  112  can keep its own trusted time that can be synchronized with the network devices during interactions with readers  108 , for example. This way the credential  112  can also control when certain message objects having a timer mechanism  420  should be activated and/or deactivated based on a reference to the internal clock. 
     With reference now to  FIG. 6 , a network analysis tool  604  will be described in accordance with at least some embodiments of the present invention. The network analysis tool  604  may reside on and be executed by a processing platform such as a server, computer, laptop, etc. The network analysis tool  604  may be used to analyze the both simulated secure access systems  200  and actual secure access systems  200 . More specifically, the network analysis tool  604  may employ an optimization agent  608  to optimize the efficiency with which information (e.g., a message object) is disseminated through an access control system having at least one non-networked message host  208 . In accordance with at least some embodiments of the present invention, the optimization agent  608  may be adapted to analyze a proposed configuration of access control devices (e.g., location and network capabilities of message hosts  204 ,  208  and number of credentials  112 ) and then suggest changes to the proposed configuration that would optimize the dissemination of message objects through the secure access system  200 . The optimization agent  608  may also be adapted to analyze actual configurations of access control devices and then either provide statistics related to the flow of message objects in the secure access system  200  or provide suggestions for optimizing the dissemination of message objects through the secure access system  200 . 
     The inputs to the network analysis tool  604  may include, for example, message host configuration information  612 , message carrier configuration information  616 , network flow information  620 , and policy dissemination requirements  624 . The message host configuration information  612  may include the number and location of message hosts  204 ,  208  in the secure access system  200  as well as each message hosts&#39; network capabilities. More specifically, the message host configuration information  612  may indicate whether a particular message host is a networked message host  204  or non-networked message host  208 , and if it is a networked message host  204  what other access control devices the networked message host  208  is capable of communicating with directly. The message host configuration information may be provided as actual data representing an actual layout of message hosts  204 ,  208  or as simulation data representing a proposed layout of message hosts  204 ,  208 . 
     The message carrier information  616  may include the number and type of message carriers  220  in the secure access system  200 . Additionally, the message carrier information  616  may define the access permissions of certain credentials  112 . This information may be worth noting in embodiments where credentials  112  are limited to sending and receiving message objects with message hosts  204 ,  208  only when they are authorized to access assets  106  or access points  104  associated with the message hosts  204 ,  208 . It is in these particular embodiments where such information will affect the dissemination of a message object through the secure access system  200 . 
     In a simulated secure access system  200 , the network flow information  620  may be estimated based on typical information flow conditions. More specifically, the network flow information  620  may be based on the actual network flow information of other secure access systems  200  having a similar configuration to the secure access system  200  being simulated. In an analysis of an actual secure access system  200 , however, the network flow information  620  may either be simulated or determined based on historical network flows of the system  200 . More specifically, the network flow information  620  may be determined by referencing the communication history  316 ,  516  of the access control devices to determine what message carriers  220  traditionally communicate with what message hosts  204 ,  208 . The level of detail of this information  620  may be based upon the level of detail of information maintained in the communication history logs  316 ,  516 . For example, if read time is stored to the second, then the same granularity of information may be incorporated into the network flow information  620 . 
     The policy dissemination requirements  624  may be user defined. These requirements may be provided in a number of different ways (e.g., either as restrictions or as goals). The policy dissemination requirements  624  specify how quickly message objects should be shared throughout a particular secure access system  200 . The policy dissemination requirements  624  may be defined in terms of a required number of access control devices (e.g., a percentage of message hosts  204 ,  208  and/or message carriers  220 ) that need to receive a particular message object within a certain time or the amount of time in which a certain number of access control devices need to receive a particular message object. 
     The network analysis tool  604  may receive all of the above-described input information and employ the optimization agent  608  to determine various ways in which message objects can be distributed through the secure access system  200  more efficiently. In accordance with at least some embodiments of the present invention, one measure of system performance as determined by the optimization agent  608  is the degree of separation between a message originating host  204 ,  208  and other message hosts  204 ,  208  or message carriers  220  in the system  200 . The degree of separation counts the minimum number of message conveying steps expected for the message object to reach a selected message host  204 ,  208  or message carrier  220  in a two-colony system (e.g., a secure access system  200  comprising networked and non-networked message hosts  204 ,  208 ). 
     In accordance with at least some embodiments of the present invention, the standard definition for connectedness, k, of a network does not satisfy the requirements of a two-colony system. The connectedness, k c , of a message carrier can be alternatively defined as the number of unique message hosts  204 ,  208  that were visited by that message carrier  220  at least once during a given time period. Similarly each message host  204 ,  208  has a value, k h , representing the number of unique message carriers  220  that it shared a transaction with during the same time period. Histograms of k for message carriers and message hosts can be used to categorize the type of network, an example of which is depicted in  FIG. 10 . 
     Most networks, in general, fit into one of three degree distribution classifications: Scale Free Networks have fat-tails, indicating more long range connections, and are characterized by a power law; Geometric Networks can be hierarchical and have an exponential distribution in k; Random Networks are more localized and follow a Poisson distribution. 
     An alternative to matching a distribution to the degree distribution is to perform spectral analysis to the message host-to-message host adjacency matrix W hh  or message carrier-to-message carrier matrix W cc  found by squaring the message carrier-to-message host adjacency matrix W ch . Spectrum of random networks will follow the Wigner Semicircle, while scale free networks will have a triangular shape. Structured networks, such as hierarchical networks, will have more complex spectra. 
     Experimental and Modeled Value of k 
     Modeling degree distribution requires two pieces of information, one is the sum of all connections, Σk, and the other is the shape of the distribution. For purposes of this illustration, the k-distribution is assumed to be exponential. 
     Measured values of Σk indicate that the total number of connections can be modeled based on the number of message carriers, n c , and the number of doors, n r    
     Sparseness of Message Carrier—Message Host Adjacency Matrix (A ch ) 
     The total sum of connections in the system  200  can be used to calculate the sparseness of the adjacency matrix. The connected fraction can be found by dividing the number of expected connections by the number of possible connections. Then the fraction of zeros, ZF, is found by subtracting the connected fraction from one. 
     
       
         
           
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     Modeling the Message Carrier-Message Host Adjacency Matrix (A ch ) 
     When the degree distribution is well known (e.g., in an actual secure access system  200 ), a general approach can be used to find an appropriate generating function for the adjacency matrix. If the degrees are assumed to follow an exponential k-distribution profile and matching constraints for the modeled value of k for both the message carrier and message host populations, then the adjacency matrix is filled by assigning random elements in A ch  a connection value of 1 based on the probability P(C, H), where C and H are message carriers and message hosts, respectively. This process is repeated until all Σk connections have been assigned. 
     Weighted Adjacency Matrix (W ch ) 
     The adjacency matrix, A, is then modified to become a weighted adjacency matrix, W, by replacing the connections in A with the event probability. The probability can be found experimentally by sampling the events from operational access control sites over a specified period of time. In the adjacency matrix, a value of one indicates that a transient connection existed at least once during the measurement period, and the weighted matrix specifies the strength of that connection. A zero in the adjacency matrix indicates a zero probability for the specified connection in the weighted matrix. 
     Plotting the number of events in each non-zero element in experimental data shows a power law distribution for the connection frequency probability mass function. 
     The probability mass function of connection strengths may follow a power-law distribution for waiting time, particularly the generalized Zipf function known as the Zipf-Mandelbrot law: 
     
       
         
           
             
               
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     One benefit of using this function in the analysis agent is the cutoff of the fat-tail typical in power law distributions by the normalization constraint, k&lt;N. The experimental value for s in the equation is very close to 2 for some systems. The analysis agent can utilize this definition of P w  by setting s=2 and defining a relationship for q based on population inputs. 
     Each element in A ch  is assigned a connection strength drawn from this distribution to create the weighted adjacency matrix, W ch . After assigning weights to W ch  the matrix, is normalized to make the sum of probabilities equal to one. 
     A bias may be utilized by the analysis agent to represent the phenomena seen in actual systems  200  to produce a probability distribution that has a higher likely connection strength in the weighted adjacency matrix W cr  for vertexes that are connecting high k colony members. The analysis agent may also modify the connection strength based on time. 
     Markov Chain Monte Carlo 
     The weighted adjacency matrix is used along with a pair of state vectors for each update issued to the system. The two state vectors respectively record which message carriers and which message hosts have received the update via a message object. At each step of a Markov Chain Monte Carlo (MCMC) a connection is randomly drawn from the weighted adjacency matrix. The states of the selected members are checked and if one and only one of the components has the update, then the update is propagated to the other member. If both or neither members has an update, then the result is null. Here interest lies in following the state vector, F, with each step rather than finding an equilibrium state (which can be assumed to be a vector of fully updated components). 
     The propagation of information in the message carrier population, Γ c , depends on both the number of message hosts that have the information, Λ r , and the number of message carriers without the knowledge of the message object available to receive a message object. Similarly the velocity of information in the message host population depends on both the number of message carriers and message hosts with the message.
 
Γ c   =f   c (Λ c ,Λ h )Γ h   =f   h (Λ c ,Λ h )
 
     Velocity, Γ, is the time (or event) derivative of the position (or number), Λ. This leads to two coupled partial differential equations in Λ, e.g. if Λ is a function of time: 
     
       
         
           
             
               
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     This codependence of information flow results in a self-limiting system where neither the message carrier population nor message host population will tend to get far ahead of the other. While this is a general rule, there are conditions where one velocity can initially be faster than the other. 
     In the equations above the velocity can be measured as either the propagation of the update per event, Λ(e) or per time, Λ(t). The natural unit used by the analysis agent in its calculations is based on events. A relationship between event units and time units can be used to convert the results to units of time. 
     Model Results 
     Performance of message delivery in an operational two colony system can be studied (e.g., by the network analysis tool  604 ) by constructing the weighted adjacency matrix, W cr , based on data from a one colony system with the conveyance of a message object being inferred when a message carrier  220  visits a first message host  204 ,  208  and then a second message host  204 ,  208 . The weighted adjacency matrix is used to propagate information in a Markov process. The simplest model has just two input values, the number of message carriers, n c , and the number of message hosts, n r . A message is initialized on one or more colony members and allowed to flow through the system. Exemplary model results (e.g., output  628 ) obtained by the network analysis tool  604  are depicted in  FIG. 11 . 
     Generally depicted on the graph is the population of either the message carriers, Λ c , or the message hosts, Λ h , modeled from actual site data (e.g., communication history logs  316 ,  516 ), that have received or were initialized with a message object. In accordance with at least one embodiment of the present invention, the line is the average of multiple MCMC trials. 
     Model Improvements 
     In accordance with at least some embodiments of the present invention, the optimization agent  608  may be operable to generate a number of different outputs  628  depending upon whether it is analyzing a proposed layout of a secure access system  200  or an actual layout of a secure access system  200 . Examples of the types of outputs  628  which may be generated by the optimization agent  608  will be discussed in further detail below. 
     Loop Events 
     Loop events are identified as diagonal components in the host-to-host adjacency matrix, W hh , where W hh  is a square matrix resulting from multiplying the weighted adjacency matrix by its transpose. These events affect the system performance by taking away from the number of possibly productive event, essentially acting to lower the effective number of events in a given time period. The optimization agent  608  may suggest configuration changes to reduce the number of loop events. 
     Time Dependent Adjacency Matrix (W cr ) 
     As mentioned earlier, connection strengths in the weighted adjacency matrix change over time. Connection strengths may have a diurnal cycle caused by variations in activity levels during the day. The connection strengths may also have weekly components due to lower activity on weekends and may also have annual cycles due to holidays, etc. Connection strengths can also change relative to each other due to periodically changing traffic patterns. In a two-colony system containing message objects transported by message carriers  220  that are constrained to pass particular message hosts  204 ,  208  there will be a beneficial effect to the efficiency of the system. Accordingly, the optimization agent  608  may provide as an output  628  suggestions to enhance connection strengths, for example by suggesting additional constraint points be included in the secure access system  200 . 
     Free Ride Events 
     In a system that constrains message carriers  220  thereby requiring them to visit specific message hosts  204 ,  208 , it may increase the possibility that one or more second message carriers  220  will “piggy back” or “tailgate” past a message host  204 ,  208  by bypassing the message host when a contemporaneous first message carrier communicates with the message host and fulfills the communication requirements. When tailgating occurs it is possible for message carriers  220  to bypass message hosts  204 ,  208  without delivering or receiving a message object. There will also be more opportunities for tailgating when the message carrier  220  population is large compared to the message host  204 ,  208  population so that the average k r  is high. Thus, the optimization agent  608  may suggest ways in which tailgating may be reduced, for example by increasing the number of message hosts  204 ,  208  in the system  200  or by suggesting additional security measures which can be taken to reduce tailgating. 
     Security Entropy 
     An important measure of a two-colony message system is its ability to maintain an environment that is current with respect to message object updates. These systems have a level of uncertainty in the currentness of information for all members in the system. The term “security entropy” is used herein to describe the chance than a message update (i.e., a message object) is available but not delivered in time due to the uncertainty in the system. A failure can be defined as an event between a message carrier  220  and a message host  204 ,  208  that occurs before the update has propagated to either member. The chance that an update will fail is the product of the chance of an event and the chance that neither member has received updated message object. The value determined by this calculation may be provided by the analysis tool in the output  628  to either help design a communication system  200  configuration or to make improvements to an operational communication system  200  configuration. 
     Improving System Performance 
     In addition to providing, as an output  628 , statistics related to the flow of information in the secure access system  200 , the network analysis tool  604  may employ the optimization agent  608  to determine if there are any ways to more quickly disseminate a message object throughout the secure access system  200 . Such determinations made by the optimization agent  608  may be provided as suggestions to a user in the form of an output  628 . Examples of such suggestions will be described in further detail below. 
     Select Individuals for Initial Update 
     The invention described in this analysis so far is generally based on the distribution of message objects in a two colony system where there the message object update is initiated with a single member and then allowed to spread throughout the system  200 . When an update is initiated through a single individual in the system (e.g., a single originating access control device), the unique characteristics of the chosen individual can have a significant impact on the system performance. It is not always possible to choose the initiation point, but in systems that provide the choice an individual in the system can be chosen to optimize cost, convenience, and performance. Typically, a high k-value is beneficial in spreading information, but it is also important to note that initializing message carriers  220  can spread information faster in the message host  204 ,  208  population and vice versa. Another important consideration is taking advantage of the constraints that cause message carriers  220  to visit particular message hosts  204 ,  208 , which has the dual benefit of producing a component with a high k-value with the additional benefit of a high connection strength with the message hosts  204 ,  208 . Furthermore, in systems with a strong diurnal cycle, the benefit from such constriction points can be most pronounced at the beginning of the day, making the system  200  efficient at distributing message objects early in the update cycle. All of these factors may be considered when the optimization agent  608  suggests an originating secure access device, which can correspond to either a message carrier  220  or message host  204 ,  208 . 
     More Connected Components 
     Having more colony members initialized with the message object update has a direct impact on the update probability, P nu (t). This improvement gives both a better starting position and a better initial rate for the update to propagate making it a useful tool for controlling performance. Accordingly, the optimization agent  608  may suggest that one or more previously non-networked message hosts  208  have their communication capabilities altered to make them become a networked message host  204 . The optimization agent  608  may also suggest which access control device the message host should be connected to. 
     Pre-Launched Updates 
     When message objects can be released into a system in advance of their eventual need then a pre-launch of the updates with a delayed “activation” will greatly improve the apparent performance of the message delivery system. The delayed activation may be facilitated by incorporating a timer mechanism  420  into the message object such that the message object is activated as some point in time after it is initially distributed into the system  200 . 
     Forced Updates 
     One of the problematic issues for message object delivery in a two colony network is the concern that an individual in one or both colonies is missed altogether in the updating process. While a well maintained system  200  may keep components updated on average, some components can miss updates for long periods of time. To address this concern a forced update can be required by the system. Forced updates can be implemented either on a regular scheduled or required after a period of inactivity. Again, the timer mechanism  420  may be utilized to have a particular message host  204 ,  208  or message carrier  220  become inactive after a predetermined amount of time unless it receives a new message object. This will force users of the message carriers  220  to go and obtain a new message object on a periodic basis. 
     A combination of Pre-Launch Updates and Forced Updates can be used to produce a zero entropy delayed-update. 
     Referring now to  FIG. 7 , a method of optimizing the configuration of a secure access system  200 , particularly in a simulation environment, will be described in accordance with at least some embodiments of the present invention. The method is initiated when the network analysis tool  604  receives message host configuration information  612  (step  704 ). The message host information  612  may include information related to the number, location, and type (e.g., networked or non-networked capabilities) of each message host  204 ,  208  in a secure access system  200 . 
     The network analysis tool  604  then receives the message carrier configuration information  616  (step  708 ). This information may include the number and types of message carriers  220  in the secure access system  200  as well as the access permissions associated with each message carrier  220 . 
     Thereafter, the network analysis tool  604  receives the network flow information  620 , which defines potential ways in which message carriers  220  will travel through the secure access system  200  (step  712 ). More specifically, the network flow information  620  may be based on data received from communication logs of other access control devices in similar secure access systems. In a simulation, the flow information  620  may also include predicted times when certain message carriers  220  will communicate with certain message hosts  204 ,  208 . 
     Once the network analysis tool  604  has received the necessary inputs to simulate the activity of the secure access system  200 , the network analysis tool  604  proceeds by generating a probability matrix based on the network flow (step  716 ). The probability matrix may include probabilities related to whether certain access control devices (e.g., message hosts  204 ,  208  and/or message carriers  220 ) will receive a message object within a predetermined time after the message object is introduced into the secure access system. Additionally, the probability matrix may also provide information showing the number of access control devices that will receive a message object within a predetermined time to within a predetermined probability. 
     A Markov process may generate the probability matrix as described above. The resulting probability matrix may then be compared to information (e.g., in the form of a message object carrying new access control policy information) flow requirements for the secure access system (step  720 ). The results of that comparison may then be provided as output  628  to a user of the network analysis tool  604  (step  724 ). More specifically, if the probabilities in the matrix meet or exceed the information flow requirements, then the network analysis tool  604  may indicate that the proposed configuration meets the requirements. Alternatively, if the information flow requirements are greatly exceeded, the network analysis tool  604  may suggest ways to decrease the cost of implementing the proposed secure access system  200 . For example, the network analysis tool  604  may indicate on the user interface which networked hosts  204  may be changed to a non-networked host  208  while still meeting the information flow requirements. This indication may be made by coloring the identified message host in a different color or shading it in a different manner from the other message hosts  204 ,  208 . Alternatively, if the information flow requirements are not met, then the network analysis tool  604  may identify certain message hosts  204 ,  208  that should either be relocated or have their communication capabilities changed. These identified message hosts  204 ,  208  may also be highlighted on the user interface and the network analysis tool  604  may further highlight the area in the premises  100  where another message host  204 ,  208  should be placed. 
     With reference now to  FIG. 8 , a method of determining information (e.g., message object) dissemination statistics will be described in accordance with at least some embodiments of the present invention. The method begins when actual host configuration information  612  and actual carrier information  616  is received at the network analysis tool  604  (steps  804  and  808 ). The actual host configuration information  612  may be retrieved directly from a server or similar type of computing platform that is controlling the secure access system  200 . Alternatively, the configuration information  612  may be input manually by a user of the network analysis tool  604 . 
     Thereafter, the information flows are simulated based on information received from the communication history logs  316 ,  516  of the message hosts  204 ,  208  and carriers  220  (step  812 ). This simulation re-creates, within a certain degree of approximation, how a message object will be distributed throughout an actual secure access system. Moreover, the historical information can be used to project future flow statistics for the same secure access system  200 . 
     After the information flow activity has been simulated, the network analysis tool  604  continues by generating the probability matrix showing the probability statistics for the information flow (step  816 ). The probability matrix may then be used to determine information dissemination statistics (step  820 ). The type of information dissemination statistics may include statistics related to how quickly a message object will be shared with the entire secure access system  200 , how quickly a message object will be shared with a certain portion of the secure access system  200 , what is the probability that a message object will be provided to a particular access control device within a predetermined time, what is the probability that a message object will not be shared with a particular access control device within a predetermined time, an indication of time needed for a message object to reach a particular access control device within a predetermined probability, and so on. 
     The network analysis tool  604  may then generate outputs  628  providing the determined information dissemination statistics to a user (step  824 ). The user may be allowed to interact with a user interface to change how the information is displayed as well as what information is displayed to the user. For example, the user may be allowed to select a particular message host on the user interface, and all of the probabilities associated with that message host (e.g., probability that it will receive a message object before a predetermined time, probability that it will not receive a message object before a predetermined time, amount of time required for it to receive a message object within a predetermined probability, number of interactions with message carriers  220  it will need before it receives the message object, etc.) as well as any other pertinent information related to the selected message host. A similar function may be performed for a selected message carrier  220  or a population of message hosts  204 ,  208  and/or message carriers  220 . 
     Referring now to  FIG. 9 , a method of optimizing the dissemination of information (e.g., message objects) through a secure access system  200  will be described in accordance with at least some embodiments of the present invention. The method is initiated when actual host  204 ,  208  and carrier  220  information is received at the network analysis tool  604  (steps  904  and  908 ). The network analysis tool  604  may then employ the optimization agent  608  to analyze the configuration of the secure access system  200  to determine if there are any ways to enhance the efficiency with which a message object is distributed throughout the system  200  (step  912 ). The optimization agent  608  may analyze past simulations as well as actual distributions of message objects for the secure access system  200  or access systems having similar configurations to the secure access system  200  under scrutiny. 
     During its analysis of the system  200  configuration the network analysis tool  604  will utilize the optimization agent  608  to determine if there are any possible constraint points in the system  200  (step  916 ). Constraint points typically correspond to points in the premises  100  where a large proportion of message carriers  220  will have to pass. Typical constraint points are entry/exit doors for the building, main entrances, lobbies, restrooms, etc. If there is at least one possible constraint point identified, then the optimization agent  608  will suggest one or more of the identified constraint points as a point where a message object should be originated (step  920 ). More specifically, the optimization agent  608  will identify access control devices (e.g., a message host  204 ,  208 ) associated with the identified constraint point and suggest that the identified message host be used as an originating access control device. Additionally, if the message host corresponds to a non-networked message host  208 , then the optimization agent  608  may also suggest that the networking capabilities of the host  208  be changed such that it becomes a networked message host  204 . This would make the introduction of the message object to the system  200  easier since a system administrator would then be able to provide the message object to the host  204  remotely rather than having to carry the message object to the message host  208  on a message carrier  220 . 
     The optimization agent  608  may also analyze the system  200  configuration to determine if there are any message carriers  220 , such as credentials  112 , which are typically more active than other message carriers  220  (step  924 ). For example, there may be certain users who have to visit a larger portion of a premises  100  than other users. As one example, often times maintenance personnel are required to visit an entire premises  100  on a daily basis whereas other types of personnel only visit certain parts of a premises regularly. The message carrier  220  associated with such active users may provide a good originating message carrier  220 . These active message carriers  220  may be identified by analyzing and comparing the communication history logs  316  of the message hosts  204 ,  208  to search for message carriers  220  that communicated with a large number of the message hosts  204 ,  208 . 
     In the event that an active message carrier  220  or a number of active message carriers  220  are identified, then the optimization agent  608  may suggest that one or more of the identified active message carriers  220  be used as an origination point for the message object (step  928 ). Such message carriers  220  may then be given a forced update to initiate the dissemination of the message object throughout the system  200 . 
     The optimization agent  608  may further analyze the system  200  to determine if a delayed update would be possible, and if so, whether such an update is allowable based on preferences of the system administrator (step  932 ). If a delayed update is possible, then the optimization agent  608  may suggest that a delayed update be performed (step  936 ). To accomplish this, the optimization agent  608  may provide a suggestion that rather than having the message object be distributed in an active fashion, the message object should be distributed with a timer mechanism, which will delay the activation of the message object (step  940 ). The optimization agent  608  may also analyze previous information dissemination statistics for the system  200  to determine the value for the timer mechanism. More specifically, the optimization agent  608  may set the value of the timer mechanism equal to the average amount of time that is required for a message object to be shared with a predetermined percentage of the access control devices in the system. For example, the value of the timer mechanism may be set equal to 2 days if it historically takes two days for 99% of the access control devices to receive a message object. 
     After the various suggestions have been generated by the optimization agent  608 , they are provided to the user of the system  200  (step  944 ). The suggested optimizations may be implemented at the discretion of the system administrator depending upon the nature and importance of the message object and the amount of security required for the secure access system  200 . 
     While the above-described flowchart has been discussed in relation to a particular sequence of events, it should be appreciated that changes to this sequence can occur without materially effecting the operation of the invention. Additionally, the exact sequence of events need not occur as set forth in the exemplary embodiments. The exemplary techniques illustrated herein are not limited to the specifically illustrated embodiments but can also be utilized with the other exemplary embodiments and each described feature is individually and separately claimable. 
     The systems, methods and protocols of this invention can be implemented on a special purpose computer in addition to or in place of the described access control equipment, a programmed microprocessor or microcontroller and peripheral integrated circuit element(s), an ASIC or other integrated circuit, a digital signal processor, a hard-wired electronic or logic circuit such as discrete element circuit, a programmable logic device such as PLD, PLA, FPGA, PAL, a communications device, such as a server, personal computer, any comparable means, or the like. In general, any device capable of implementing a state machine that is in turn capable of implementing the methodology illustrated herein can be used to implement the various data messaging methods, protocols and techniques according to this invention. 
     Furthermore, the disclosed methods may be readily implemented in software (e.g., as instructions stored on a computer-readable medium) using object or object-oriented software development environments that provide portable source code that can be used on a variety of computer or workstation platforms. Alternatively, the disclosed system may be implemented partially or fully in hardware using standard logic circuits or VLSI design. Whether software or hardware is used to implement the systems in accordance with this invention is dependent on the speed and/or efficiency requirements of the system, the particular function, and the particular software or hardware systems or microprocessor or microcomputer systems being utilized. The analysis systems, methods and protocols illustrated herein can be readily implemented in hardware and/or software using any known or later developed systems or structures, devices and/or software by those of ordinary skill in the applicable art from the functional description provided herein and with a general basic knowledge of the computer arts. 
     Moreover, the disclosed methods may be readily implemented in software that can be stored on a storage medium, executed on a programmed general-purpose computer with the cooperation of a controller and memory, a special purpose computer, a microprocessor, or the like. In these instances, the systems and methods of this invention can be implemented as program embedded on personal computer such as an applet, JAVA® or CGI script, as a resource residing on a server or computer workstation, as a routine embedded in a dedicated communication system or system component, or the like. The system can also be implemented by physically incorporating the system and/or method into a software and/or hardware system, such as the hardware and software systems of a communications device or system. 
     It is therefore apparent that there has been provided, in accordance with the present invention, systems, apparatuses and methods for optimizing data messaging in a secure access system having at least one non-networked reader. While this invention has been described in conjunction with a number of embodiments, it is evident that many alternatives, modifications and variations would be or are apparent to those of ordinary skill in the applicable arts. Accordingly, it is intended to embrace all such alternatives, modifications, equivalents and variations that are within the spirit and scope of this invention.