Abstract:
A representational state transfer-based model for a computing environment uses models resources with links between them. Security principals are resources which can be independently authenticated. Each resource may be associated with an authorization policy that determines level of access, protocol supported. Successfully presenting security credentials at a security principal allows use of an instance of the security principal (i.e. application) as well as generation of an authentication token that can be presented across the computing environment to resources subscribing to the same authorization policy. As security principals with different security policies are authenticated, the appropriate tokens may be combined to allow broader access without undue re-authentication for resources subscribing to the same security policy. Authorization requirements (policies) may be attached to links to resources so that an application instance can dynamically discover authentication rules for that resource by inspecting the link.

Description:
RELATED APPLICATION 
       [0001]    This application is a continuation-in-part of co-pending U.S. patent application Ser. No. 12/042,637, filed Mar. 4, 2008, the entire disclosure of which is hereby incorporated by reference for all purposes. 
     
    
     BACKGROUND 
       [0002]    The success of the Web and email may be due to their scalability and interoperability. In part, such scalability and interoperability are enabled by standardized message formats, protocols, and addressing schemes. The Web in particular takes advantage of URI (universal resource identifier) addressing to find endpoints. Traditionally, endpoints were software components supporting remote procedure calls. However, a new model for network-based computing uses a representational state transfer (REST) paradigm. In the REST paradigm, sources of specific information are called resources and are identified, typically, by a URI. A connector can mediate the requests made for resources. Servers, caches, tunnels, etc., are all examples of connectors. Each may make or forward a request without explicit knowledge of where the actual resource may be. 
         [0003]    Resources may be owned by one entity, hosted by another entity, and support connectors may be from virtually anywhere. Varying requirements for security resulting from this variety may prevent transparent operation of such a mesh of resources, because different participants may have different requirements for security. In addition, not all participants may support the same security processes and protocols. 
         [0004]    For example, one resource owner may require public key authentication and support only elliptic curve key types. However, a requester attempting to use that resource may support only RSA key types. Further, the requester may have to traverse a network that requires an SSL2 secure communication protocol for transport sercurity while another path may not. 
       SUMMARY 
       [0005]    A computing environment, including both client and cloud computing entities, may be modeled as resources with relationships between them modeled as links. An authenticatable entity is modeled as a security principal. When a security principal, for example, a user, device, or application, issues a request against a resource, the cloud may invoke an authentication engine to examine an authentication policy or policies in place for that resource. The security principal&#39;s credentials may be examined with respect to the authentication policy or policies, and, if found acceptable, the authentication engine may grant access to the resource and issue an authentication token for use by an instance of the resource to use in related requests to other resources. The authentication token may also be used to allow the security principal, for example, a user, more elevated access to the resource (e.g. granting admin rights). 
         [0006]    Any links to the resource may also include authorization token links so that an application instance can discover any authorization requirements by inspecting all resource links for authorization token links. 
         [0007]    More than one authentication policy may be associated with a resource. For example, a resource may have a policy associated with the resource owner as well as the resource host. A policy may describe requirements for use of the resource, requirements for access to the resource (e.g. administrative access), security protocols supported by the resource, etc. The policy may also include operational rules, for example, that one CPU is granted per authorization. 
         [0008]    As described in the above-referenced related application, a combination of resource caching and resource synchronization may allow the use of the authentication scheme by both client-based applications and cloud-based applications or services. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  illustrates a example of a computer capable of supporting operations in a cloud computing environment; 
           [0010]      FIG. 2  illustrates a cloud computing environment supporting flexible scalable application authorization; and 
           [0011]      FIG. 3  illustrates a method of performing flexible scalable application authorization. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    Although the following text sets forth a detailed description of numerous different embodiments, it should be understood that the legal scope of the description is defined by the words of the claims set forth at the end of this patent. The detailed description is to be construed as exemplary only and does not describe every possible embodiment since describing every possible embodiment would be impractical, if not impossible. Numerous alternative embodiments could be implemented, using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims. 
         [0013]    It should also be understood that, unless a term is expressly defined in this patent using the sentence “As used herein, the term ‘______’ is hereby defined to mean . . . ” or a similar sentence, there is no intent to limit the meaning of that term, either expressly or by implication, beyond its plain or ordinary meaning, and such term should not be interpreted to be limited in scope based on any statement made in any section of this patent (other than the language of the claims). To the extent that any term recited in the claims at the end of this patent is referred to in this patent in a manner consistent with a single meaning, that is done for sake of clarity only so as to not confuse the reader, and it is not intended that such claim term by limited, by implication or otherwise, to that single meaning. Finally, unless a claim element is defined by reciting the word “means” and a function without the recital of any structure, it is not intended that the scope of any claim element be interpreted based on the application of 35 U.S.C. §112, sixth paragraph. 
         [0014]    With reference to  FIG. 1 , an exemplary system for implementing the claimed method and apparatus includes a general purpose computing device in the form of a computer  110 . Components shown in dashed outline are not technically part of the computer  110 , but are used to illustrate the exemplary embodiment of  FIG. 1 . Components of computer  110  may include, but are not limited to, a processor  120 , a system memory  130 , a memory/graphics interface  121 , also known as a Northbridge chip, and an I/O interface  122 , also known as a Southbridge chip. The system memory  130  and a graphics processor  190  may be coupled to the memory/graphics interface  121 . A monitor  191  or other graphic output device may be coupled to the graphics processor  190 . 
         [0015]    A series of system busses may couple various system components including a high speed system bus  123  between the processor  120 , the memory/graphics interface  121  and the I/O interface  122 , a front-side bus  124  between the memory/graphics interface  121  and the system memory  130 , and an advanced graphics processing (AGP) bus  125  between the memory/graphics interface  121  and the graphics processor  190 . The system bus  123  may be any of several types of bus structures including, by way of example, and not limitation, such architectures include Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MCA) bus and Enhanced ISA (EISA) bus. As system architectures evolve, other bus architectures and chip sets may be used but often generally follow this pattern. For example, companies such as Intel and AMD support the Intel Hub Architecture (IHA) and the Hypertransport™ architecture, respectively. 
         [0016]    The computer  110  typically includes a variety of computer readable media. Computer readable media can be any available media that can be accessed by computer  110  and includes both volatile and nonvolatile media, removable and non-removable media. By way of example, and not limitation, computer readable media may comprise computer storage media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can accessed by computer  110 . 
         [0017]    The system memory  130  includes computer storage media in the form of volatile and/or nonvolatile memory such as read only memory (ROM)  131  and random access memory (RAM)  132 . The system ROM  131  may contain permanent system data  143 , such as identifying and manufacturing information. In some embodiments, a basic input/output system (BIOS) may also be stored in system ROM  131 . RAM  132  typically contains data and/or program modules that are immediately accessible to and/or presently being operated on by processor  120 . By way of example, and not limitation,  FIG. 1  illustrates operating system  134 , application programs  135 , other program modules  136 , and program data  137 . 
         [0018]    The I/O interface  122  may couple the system bus  123  with a number of other busses  126 ,  127  and  128  that couple a variety of internal and external devices to the computer  110 . A serial peripheral interface (SPI) bus  126  may connect to a basic input/output system (BIOS) memory  133  containing the basic routines that help to transfer information between elements within computer  110 , such as during start-up. 
         [0019]    A super input/output chip  160  may be used to connect to a number of ‘legacy’ peripherals, such as floppy disk  152 , keyboard/mouse  162 , and printer  196 , as examples. The super I/O chip  160  may be connected to the I/O interface  122  with a bus  127 , such as a low pin count (LPC) bus, in some embodiments. Various embodiments of the super I/O chip  160  are widely available in the commercial marketplace. 
         [0020]    In one embodiment, bus  128  may be a Peripheral Component Interconnect (PCI) bus, or a variation thereof, may be used to connect higher speed peripherals to the I/O interface  122 . A PCI bus may also be known as a Mezzanine bus. Variations of the PCI bus include the Peripheral Component Interconnect-Express (PCI-E) and the Peripheral Component Interconnect-Extended (PCI-X) busses, the former having a serial interface and the latter being a backward compatible parallel interface. In other embodiments, bus  128  may be an advanced technology attachment (ATA) bus, in the form of a serial ATA bus (SATA) or parallel ATA (PATA). 
         [0021]    The computer  110  may also include other removable/non-removable, volatile/nonvolatile computer storage media. By way of example only,  FIG. 1  illustrates a hard disk drive  140  that reads from or writes to non-removable, nonvolatile magnetic media. The hard disk drive  140  may be a conventional hard disk drive. 
         [0022]    Removable media, such as a universal serial bus (USB) memory  153 , firewire (IEEE 1394), or CD/DVD drive  156  may be connected to the PCI bus  128  directly or through an interface  150 . A storage media  154  may coupled through interface  150 . Other removable/non-removable, volatile/nonvolatile computer storage media that can be used in the exemplary operating environment include, but are not limited to, magnetic tape cassettes, flash memory cards, digital versatile disks, digital video tape, solid state RAM, solid state ROM, and the like. 
         [0023]    The drives and their associated computer storage media discussed above and illustrated in  FIG. 1 , provide storage of computer readable instructions, data structures, program modules and other data for the computer  110 . In  FIG. 1 , for example, hard disk drive  140  is illustrated as storing operating system  144 , application programs  145 , other program modules  146 , and program data  147 . Note that these components can either be the same as or different from operating system  134 , application programs  135 , other program modules  136 , and program data  137 . Operating system  144 , application programs  145 , other program modules  146 , and program data  147  are given different numbers here to illustrate that, at a minimum, they are different copies. A user may enter commands and information into the computer  20  through input devices such as a mouse/keyboard  162  or other input device combination. Other input devices (not shown) may include a microphone, joystick, game pad, satellite dish, scanner, or the like. These and other input devices are often connected to the processor  120  through one of the I/O interface busses, such as the SPI  126 , the LPC  127 , or the PCI  128 , but other busses may be used. In some embodiments, other devices may be coupled to parallel ports, infrared interfaces, game ports, and the like (not depicted), via the super I/O chip  160 . 
         [0024]    The computer  110  may operate in a networked environment using logical connections to one or more remote computers, such as a remote computer  180  via a network interface controller (NIC)  170 . The remote computer  180  may be a personal computer, a server, a router, a network PC, a peer device or other common network node, and typically includes many or all of the elements described above relative to the computer  110 . The logical connection between the NIC  170  and the remote computer  180  depicted in  FIG. 1  may include a local area network (LAN), a wide area network (WAN), or both, but may also include other networks. Such networking environments are commonplace in offices, enterprise-wide computer networks, intranets, and the Internet. The remote computer  180  may also represent a web server supporting interactive sessions with the computer  110 , or in the specific case of location-based applications may be a location server or an application server. 
         [0025]    In some embodiments, the network interface may use a modem (not depicted) when a broadband connection is not available or is not used. It will be appreciated that the network connection shown is exemplary and other means of establishing a communications link between the computers may be used. 
         [0026]      FIG. 2  illustrates a computing environment  200  including a client entity  202  and a computing cloud  204 . As described in the related application noted above, a ticketing system adapted for use with a cloud-based services platform is provided by a ticket-based authorization model in which the authorization requirements for traversing a mesh of resources associated with a cloud service are annotated in the links used by resources to refer to other resources. The meshes are thus self-describing with respect to the association (i.e., the links) between resources as well as the authorization required to access resources. Resource access employs a principal ticket which asserts that a caller at a client (e.g., a security principal representing a device or identity associated with a user) is authenticated, plus zero or more claim tickets. The claim tickets make additional assertions about the caller that the cloud service may use to check to determine that the caller is authorized to access the resource. The principal and claim tickets are signed so that their authenticity may be checked by the cloud service. 
         [0027]    When a resource in a mesh requires a claim ticket for access, the requirement is expressed by including a URI (Universal Resource Identifier) that identifies where the claim ticket may be retrieved as an attribute on links to that resource. Optionally, a resource link may be arranged to include an inline value of the required claim ticket as an attribute which eliminates the extra step of retrieving the required claim ticket. By associating links to the resources with the authorization requirements for accessing the resources, a client can traverse a mesh and access its resources while obtaining the required claim tickets along the way. 
         [0028]    As illustrated in  FIG. 2 , the client entity  202  may include one or more of a user  206 , a device  208 , an application  210 , etc. One feature of the elements of the client entity  202  is that each is authenticable. 
         [0029]    The cloud-based services platform, or simply, the computing cloud  204 , may include a number of resources that are navigable by links or references. For example, in  FIG. 2 , resources include R 0   212 , R 1   214 , R 2   216 , R 3   218 , and R 4   220 . 
         [0030]    The resources may each have an associated security policy P 1   222 , P 2   224 , or more (not depicted). The security policies may be stored in a policy repository  226 . Each security policy  222 ,  224 , etc. may be related to a party with an interest in the resource. For example, a first security policy P 1   222  may specify access criteria specified by an owner of the resource used to limit what users may access the resource. Additional first security policy P 1  criteria may describe what credentials must be presented for higher level, e.g. administrator, access to the resource. The first security policy P 1   222  may also include additional access criteria, protocols, cryptographic algorithms, key lengths, etc. 
         [0031]    A second security policy P 2   224 , may represent the interests of a host of the resource, for example, specifying required authentication protocols, such as RSA public key over an SSL2 transport. As with the first security policy P 1 , the second security policy P 2  may also specify additional access conditions, protocols, cryptographic algorithms, key lengths, etc. 
         [0032]    As depicted in  FIG. 2 , a resource may be associated with one or more security policies, or in the case of resource R 4   220 , may not have any security policy. 
         [0033]    An authentication engine  228  may handle requests made for access to a resource, for example, a request from application  210  for access to resource R 0   212 . The request may include the security credentials of the application  210 , such as a ID/password or signed challenge response. In one embodiment, the request uses an HTTP protocol with an authentication header and token. 
         [0034]    The authentication engine  228  may examine the credentials and evaluate them in view of the appropriate security policies that may be in place for the selected resource. When the security policy is met by the credential, one or more authorization tokens T 1   230 , T 2   232 , or T 3   234  may be generated. The tokens  230 ,  232 ,  234 , etc. may be stored in a token repository  236 . 
         [0035]    Additionally, authorization token links  238 ,  240 , and  242  may be attached to relevant links so that in traversing links to resources, an application instance may find a link to the token repository  236 , or other resource, from which the authorization token may be retrieved upon successfully satisfying the associated authentication requirements. It is therefore possible to dynamically discover any authorization requirements by inspecting all resource links to detect the presence of authorization token links. In this fashion, authorization rules for the computing environment are self-describing. 
         [0036]    In operation, the security principal  202 , be it a user with a LiveID credential, a first or third party application  210 , such as a code function or gadget, may request services from the computing cloud  204 . The request and credentials may be passed to a resource  212  and the credentials and related security policy verified at the authentication engine  228 . 
         [0037]    The authentication engine  228  may generate one or more tokens  230 ,  232 ,  234 . Should the resource  212  need to make subsequent calls to additional resources, e.g. R 1  or R 2 ,  214  or  216 , respectively, the links to the resources may be examined for authorization token links  238  and  240  to determine the appropriate security requirements and to retrieve the previously generated tokens if required. When the representation returned for R 0   212  contains links to resources R 2   216  and R 1   214 , each link is annotated with an authorization token link as a link attribute. The authorization token link for R 1   214  refers to T 1   230  and the authorization token link for R 2   216  refers to T 2   232 . 
         [0038]    Before issuing a request to interact with resource R 1   214 , the client must first issue a request to T 1  to obtain an authorization token. The authorization engine may generate the requested authorization token on demand, based on the security credentials provided by the client. 
         [0039]    As more resources are traversed, the client can build up a dictionary of entries for each resource link, remembering which authorization tokens were needed in order to interact with that resource. This reduces the need to repeatedly obtain authorization tokens for resources that it interacts with multiple times. 
         [0040]    This process allows abstraction of security policies, authentication, and resource traversal, reducing overhead in both storage of policies and tokens, and of computing power used to repetitively validate credentials. Further, because the authorization rules are self describing, additional overhead to maintain databases of security status and pointers are eliminated. This abstraction applies to both first and third party security principals whether inside or outside the computing cloud  204 . 
         [0041]      FIG. 3  illustrates a method  300  of performing application authentication in a cloud computing environment, for example, the cloud computing environment  200  of  FIG. 2 . The cloud computing environment  200  may include a plurality of resources that may be exposed to a requesting entity. One or more security principals, i.e. authenticatable entities, may be associated with the cloud computing environment  200  and may request access to or services from one or more of the resources. Internal to the cloud computing environment  200 , one resource may request access to or services from another resource. At block  302 , a security policy  222  may be created and associated with at least one resource. More than one security policy may be generated and more than one security policy may be associated with a single resource. 
         [0042]    The security policy  222  may specify a credential requirement for use of the resource or for access to the resource. That is, one level of credential may allow use of a program or gadget, while another credential may allow the requester to access the resource, for example, as an administrator to perform a maintenance function. The security policy  222  may specify a cryptographic policy, such as requiring the use of 3DES or RSA public keys and/or a minimum key strength. One security policy applied to a resource may be associated with a first entity having an interest in the resource, for example an owner of the resource. Another security policy applied to the same resource may be associated with a second entity having an interest in the resource, such as a host of the resource. Other parties with an interest in the resource who may also contribute to additional security policies may include an author, a security monitor, an auditor, etc. 
         [0043]    In one embodiment, a set of standard policies may be developed and stored that may be associated with one or more resources. The use of standard policies can minimize the risk of a missed criteria as well as create a more uniform security environment. 
         [0044]    At block  304  the cloud computing environment  200  may receive a request from a security principal to access a resource. The request may include a security credential of the security principal. When receiving the request for access, the cloud computing environment  200  may route the request to an authentication engine  228  instead of or in addition to routing the request to the correct resource. 
         [0045]    At block  306 , the authentication engine  228  may determine which, if any, security policies may be applicable to the requested resource. The authentication engine  228  may then determine whether the credentials presented satisfy the requirements of the security policy  226 . If the credentials do not satisfy the requirements, the process ends. Assuming the credentials meet the requirements of the security policy  222 , e.g. both the protocol and key data requirements of the security policy, execution may continue. 
         [0046]    At block  308 , the authorization engine  228  may generate an authorization token  230  when the security credential satisfies the at least one security policy  222 . The authorization engine  228  may generate a token for the requested resource. The authentication engine  228  may generate a token for each security policy in the mesh for which the supplied credential satisfies its requirements. The one or more authorization tokens may be stored in a token repository  236 . Alternatively, as a link is traversed, the policy may be discovered and a token generated. In either case, the authentication engine  228  may generate a separate authentication token for each security policy successfully authenticated. 
         [0047]    At block  310 , security policy-related information may be attached to a resource link used to traverse to the resource. The security policy-related information may correspond to the one or more security policies attached to the resource. The security policy-related information may be an authorization token link  238  identifying a second resource from which the authorization token is retrievable. 
         [0048]    At block  312 , security policy information attached to the resource link, e.g. an authorization token link  238 , may be inspected to determine a security requirement for the resource. In this manner, even as the resources are realigned in the mesh, the security requirements are self-describing. 
         [0049]    Returning to block  314 , after one or more authentication tokens are generated, the resource may forward an authentication token from an instance of the resource, that is, a specific incarnation of the resource related to operation related to the request, to another resource. Such use of authentication tokens eliminates the need for successive authentication each time an entity is accessed related to the first request.