PATENT DOCUMENT

Publication Number: US-11475106-B2
Application Number: US-201816177250-A
Country: US
Kind Code: B2

Title: Application usage policy enforcement

Abstract:
Disclosed herein are systems, methods, and non-transitory computer-readable media for enforcing application usage policies. As part of an application purchase transaction, the application distributor creates a unique proof of purchase receipt. This receipt can be bundled with the application and delivered to the purchaser. Each machine can maintain an authorization file that lists the users authorized to use applications on that machine. A system configured to practice the method verifies that a user is authorized to use an application on a machine based on an application proof of purchase receipt and the authorization file. If the application proof of purchase receipt and the authorization file are both valid, the system checks if the user account identifier in the receipt is contained in the authorization file. If so, the user can be considered authorized to use the application on the machine.

Claims:
What is claimed is: 
     
       1. A method for managing an application, the method comprising, at a client device associated with a user account:
 sending a first request to a server device to acquire the application; 
 receiving from the server device, the application and a receipt including a de-authorization count that indicates a limit on a number of client devices associated with the user account that are authorized to execute the application; and 
 in conjunction with launching the application on the client device, and by the application:
 sending, to the server device, a second request to authorize the client device to execute the application, wherein the second request includes an authorization file having the de-authorization count, 
 receiving, from the server device an updated authorization file that includes an updated de-authorization count associated with the user account that indicates that the client device is authorized to execute the application, 
 performing a verification step by comparing the de-authorization count in the receipt against the updated de-authorization count in the updated authorization file and, 
 in response to determining that the verification step is unsuccessful:
 quitting execution of the application. 
 
 
 
     
     
       2. The method of  claim 1 , wherein:
 the verification step is unsuccessful when the receipt or updated authorization file is invalid; and 
 the verification step is successful when the receipt and updated authorization file is valid. 
 
     
     
       3. The method of  claim 2 , wherein the receipt or updated authorization file is invalid when the de-authorization count included in the receipt is greater than the updated de-authorization count included in the updated authorization file. 
     
     
       4. The method of  claim 3 , wherein the receipt and updated authorization file is valid when the de-authorization count is less than or equal to the updated de-authorization count. 
     
     
       5. The method of  claim 1 , wherein the updated authorization file includes a digital signature that is formed based on a private key of the server device. 
     
     
       6. The method of  claim 1 , wherein the first request includes a unique account identifier associated with the client device, and the updated authorization file includes the unique account identifier. 
     
     
       7. A client device configured to manage an application, the client device comprising: at least one processor; and at least one memory storing instructions that, in response to being executed by the at least one processor, cause the client device that is associated with a user account to carry out steps that include:
 sending a first request to a server device to acquire the application; 
 receiving from the server device, the application and a receipt including a de-authorization count that indicates a limit on a number of client devices associated with the user account that are authorized to execute the application; and 
 in conjunction with launching the application on the client device, and by the application:
 sending, to the server device, a second request to authorize the client device to execute the application, wherein the second request includes an authorization file having the de-authorization count, 
 receiving, from the server device an updated authorization file that includes an updated de-authorization count associated with the user account that indicates that the client device is authorized to execute the application, 
 performing a verification step by comparing the de-authorization count in the receipt against the updated de-authorization count in the updated authorization file and, 
 in response to determining that the verification step is unsuccessful:
 quitting execution of the application. 
 
 
 
     
     
       8. The client device of  claim 7 , wherein:
 the verification step is unsuccessful when the receipt or updated authorization file is invalid; and 
 the verification step is successful when the receipt and updated authorization file is valid. 
 
     
     
       9. The client device of  claim 8 , wherein the receipt or updated authorization file is invalid when the de-authorization count included in the receipt is greater than the updated de-authorization count included in the updated authorization file. 
     
     
       10. The client device of  claim 9 , wherein the receipt and updated authorization file is valid when the de-authorization count is less than or equal to the updated de-authorization count. 
     
     
       11. The client device of  claim 7 , wherein the updated authorization file includes a digital signature that is formed based on a private key of the server device. 
     
     
       12. The client device of  claim 7 , wherein the first request includes a unique account identifier associated with the client device, and the updated authorization file includes the unique account identifier. 
     
     
       13. At least one non-transitory computer readable storage medium storing instructions that, when executed by at least one processor included in a client device, cause the client device that is associated with a user account to carry out steps that include:
 sending a first request to a server device to acquire the application; 
 receiving from the server device, the application and a receipt including a de-authorization count that indicates a limit on a number of client devices associated with the user account that are authorized to execute the application; and 
 in conjunction with launching the application on the client device, and by the application:
 sending, to the server device, a second request to authorize the client device to execute the application, wherein the second request includes an authorization file having the de-authorization count, 
 receiving, from the server device an updated authorization file that includes an updated de-authorization count associated with the user account that indicates that the client device is authorized to execute the application, 
 performing a verification step by comparing the de-authorization count in the receipt against the updated de-authorization count in the updated authorization file and, 
 in response to determining that the verification step is unsuccessful:
 quitting execution of the application. 
 
 
 
     
     
       14. The at least one non-transitory computer readable storage medium of  claim 13 , wherein:
 the verification step is unsuccessful when the receipt or updated authorization file is invalid; and 
 the verification step is successful when the receipt and updated authorization file is valid. 
 
     
     
       15. The at least one non-transitory computer readable storage medium of  claim 14 , wherein the receipt or updated authorization file is invalid when the de-authorization count included in the receipt is greater than the updated de-authorization count included in the updated authorization file. 
     
     
       16. The at least one non-transitory computer readable storage medium of  claim 15 , wherein the receipt and updated authorization file is valid when the de-authorization count is less than or equal to the updated de-authorization count. 
     
     
       17. The at least one non-transitory computer readable storage medium of  claim 13 , wherein the updated authorization file includes a digital signature that is formed based on a private key of the server device. 
     
     
       18. The at least one non-transitory computer readable storage medium of  claim 13 , wherein the first request includes a unique account identifier associated with the client device, and the updated authorization file includes the unique account identifier.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. application Ser. No. 12/907,915, filed Oct. 19, 2010, entitled “APPLICATION USAGE POLICY ENFORCEMENT,” which is incorporated herein by reference in its entirety for all purposes. 
    
    
     FIELD 
     The present disclosure relates to enforcing application usage policies and more specifically to preventing unauthorized execution of an application on a computer. 
     BACKGROUND 
     An important feature of computer software is that a single piece of software can be installed on multiple machines without a need to alter the software. This is advantageous for the software developer because they can develop the software once and then distribute it to many different users without any additional work. It is also advantageous for the user because he or she can move their software from one machine to another, for example, when the user buys a new computer. Software portability also makes it possible for a user to buy a single copy of the software and simultaneously install it on multiple computers, which in some situations may be undesirable. For example, some software may be very costly to produce and have a very small target market. In this case, unauthorized copying may prevent the developer from recouping their costs. 
     To prevent unauthorized copying, software developers often employ an installation process that requires a unique product key for each installation of the software. This approach prevents unauthorized copying, but it also makes it difficult for a user to migrate from one machine to another. Furthermore, this solution is cumbersome when a software developer has a policy that allows a user to install the software on a specified number of machines. 
     SUMMARY 
     Additional features and advantages of the disclosure will be set forth in the description which follows, and in part will be obvious from the description, or can be learned by practice of the herein disclosed principles. The features and advantages of the disclosure can be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features of the disclosure will become more fully apparent from the following description and appended claims, or can be learned by the practice of the principles set forth herein. 
     Disclosed herein are systems, methods, and non-transitory computer-readable storage media for enforcing application usage policies. 
     In an application server embodiment, a system configured to practice the method is configured to receive a purchase request. In response to the request, the system can create a proof of purchase receipt for that purchase. The receipt can include various pieces of information about the purchase transaction, such as the user&#39;s account identifier, the application identifier, the application version number, the purchase date, and parental control ratings for the application. The system can sign the receipt, bundle it with the application, and send the application bundle to the requesting client device. 
     In a client device embodiment, when a user wants to use an application on a machine, the system can verify that the usage adheres to the usage policies. When a user purchases an application, an application proof of purchase receipt is included with the application. To run the purchased application on a particular client device, the account identifier associated with the purchased application must be authorized on the client device. Each client device can maintain an authorization file that can specify a client identifier for that client machine and all of the user identifiers authorized to use applications on that client device. When a user attempts to use an application, the system can verify that the proof of purchase receipt and the authorization file are valid. Additionally, the system can verify that the user specified in the proof of purchase receipt is in the authorization file. In some embodiments, if the user is not in the authorization file, the system can make a request to authorize the user. 
     As an example enforcement mechanism, the system can include a de-authorization counter to try to prevent a user from circumventing the application usage policy. A de-authorization count field can be included in the application proof of purchase receipt and the authorization file. A de-authorization count can also be maintained by the system. When a user makes a request to purchase an application, the system can construct a proof of purchase receipt for that purchase which includes the current de-authorization count for the user. When a user attempts to use an application, the system can verify that proof of purchase receipt and the authorization file are valid. Additionally, the system can verify that the user specified in the proof of purchase receipt is in the authorization file. Finally, the system can verify that the de-authorization count in the receipt is less than or equal to the de-authorization count in the authorization file. This enforcement mechanism can provide a simple way for a user to transfer the application a set number of times, according to the terms of the application usage policy. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to describe the manner in which the above-recited and other advantages and features of the disclosure can be obtained, a more particular description of the principles briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only exemplary embodiments of the disclosure and are not therefore to be considered to be limiting of its scope, the principles herein are described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
         FIG. 1  illustrates an exemplary system configuration for application distribution and usage; 
         FIG. 2  illustrates an exemplary application purchase; 
         FIG. 3  illustrates an exemplary application purchase receipt; 
         FIG. 4  illustrates an exemplary method embodiment for application purchase; 
         FIG. 5  illustrates an exemplary authorization file; 
         FIG. 6  illustrates an exemplary authorization request; 
         FIG. 7  illustrates an exemplary scenario for authorization on purchase; 
         FIG. 8  illustrates an exemplary method for authorization on application launch; 
         FIG. 9  illustrates an exemplary method embodiment for application verification; 
         FIG. 10  illustrates exemplary application purchase receipt and authorization file with de-authorization counters; 
         FIG. 11  illustrates an exemplary method embodiment for application verification using de-authorization counters; 
         FIG. 12  illustrates an exemplary de-authorization counter usage scenario; and 
         FIG. 13  illustrates an exemplary system embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Various embodiments of the disclosure are discussed in detail below. While specific implementations are discussed, it should be understood that this is done for illustration purposes only. A person skilled in the relevant art will recognize that other components and configurations may be used without parting from the spirit and scope of the disclosure. The present disclosure addresses the need in the art for improved methods of selecting targeted content presented to a user based on characteristics descriptive of the user and/or the user&#39;s interaction with one or more items of targeted content. 
     The presently disclosed system and method is particularly useful for enforcing application usage policies on a computer. An exemplary system configuration  100  for application distribution and usage is illustrated in  FIG. 1 , wherein electronic devices  102 ,  104  communicate via a network  110  with an electronic application distributor  112 . The system can be configured for use on a wide area network, such as that illustrated in  FIG. 1 . However, the present principles are applicable in a wide variety of network configurations that facilitate the intercommunication of electronic devices. For example, each of the components of system  100  in  FIG. 1  can be implemented in a localized or distributed fashion in a network. 
     In system  100 , the user terminals  102  and  104  interact with the application distributor  112 , via direct and/or indirect communication, to obtain computer programs, also known as applications. Any number or type of user terminals can interact with the application distributor  112 . For example, a user terminal  102  can be a desktop computer; a laptop computer; a handheld communication device, e.g., mobile phone, smart phone, tablet, or any other type of device connecting using multiple or non-persistent network sessions; etc. The user terminal  102  makes a request, such as a purchase request, to the application distributor  112 . The application distributor  112  responds by either delivering the requested content to the requesting user terminal  102  or denying the request. A request can be denied, for example, due to a failure on the part of the user terminal  102  to supply an adequate method of payment. 
     To facilitate enforcement of application usage policies, the application distributor can provide the requesting user terminal an application proof of purchase receipt along with the purchased application.  FIG. 2  illustrates an exemplary application purchase  200 . In the exemplary application purchase  200 , the user terminal  102  makes a purchase request to the application distributor  112 . As part of the purchase request, the user terminal  102  can provide account information for the requesting user. In some configurations, the account information can be a username and password. In other configurations, the account authorization can occur as a separate interaction with the application distributor  112  and thus, the account information can be a unique account identifier, such as a DSid. After receiving the purchase request, the application distributor  112  can create an application bundle  206  composed of the application  208  and the application proof of purchase receipt  210 . The application distributor  112  can then deliver the application bundle  206  to the user terminal  102 . As will be discussed in more detail below, the application proof of purchase receipt can be used at a later time to aid in enforcing a usage policy for the application. 
     A purchase transaction includes any kind of transaction for a recipient to obtain an application and does not necessarily require an exchange of money or other value. The purchase transaction can include a third party giving the application as a gift to the recipient, or the recipient can redeem a coupon, promotional code, or similar instrument in exchange for the application. In some cases, a purchase request can be made for a free application. Regardless of whether a monetary exchange is required to obtain the application, the application distributor can provide an application proof of purchase receipt with the application. 
     An application proof of purchase receipt can include a variety of information, as illustrated in the exemplary proof of purchase receipt  300  in  FIG. 3 . The application proof of purchase receipt can include more or less information than is shown in  FIG. 3 . The proof of purchase receipt body  302  can include various account information associated with the user who purchased the application. The user can be an individual, a group of individuals, or an organization. The account information can include the user&#39;s ID, such as a username. The account information can also include a unique account identifier for the user, such as the DSid. In some configurations, instead of including the plaintext DSid, the proof of purchase receipt body  302  can include a unique representation of the DSid. For example, the unique representation can be a one-way representation of DSid, e.g., f(DSid). In some cases, the unique representation can be used to improve security of the receipt and/or user privacy. The proof of purchase receipt body  302  can also include various pieces of information about the purchased application. For example, the proof of purchase receipt body  302  can include the ID, the version number, and the parent control rating of the purchased application. In some cases, additional information about the application can be included in the receipt, such as an application signature. Additionally, the proof of purchase receipt body  302  can include the purchase date. 
     In some configurations, an application proof of purchase receipt body  302  can include additional and/or alternative information. Furthermore, the organization of the information within the proof of purchase receipt  300  can vary with the configuration of the system. In one variation, a server retains a full or partial copy of the application proof of purchase receipt  300 . 
     In some configurations, the proof of purchase receipt  300  can be in plaintext, which would make it readable to any user that can understand the file layout. To prevent and/or detect unauthorized modification of the proof of purchase receipt  300 , the proof of purchase receipt  300  can include a receipt signature  304 . The receipt signature  304  can be any digital signature that can be used to detect unauthorized modification of the proof of purchase receipt. For example, the application distributor  112  can use a cryptographic hash function to generate a digital signature of the proof of purchase receipt body  302 . In some configurations, the application distributor  112  can use a public key system to generate the digital signature. In this case, the application distributor  112  uses its private key to generate the receipt signature  304 . A user terminal, the application distributor, and/or any other device with access to the application distributor&#39;s public key can then verify the receipt  300 . Alternatively, the application distributor  112  can use a private key system to generate the receipt signature  304 . In this case, unless the application distributor  112  shares its private key, only the application distributor can verify the receipt  300 . 
       FIG. 4  is a flowchart illustrating steps in an exemplary method  400  for an application purchase that includes a proof of purchase receipt. For the sake of clarity, this method is discussed in terms of an exemplary system such as is shown in  FIG. 1 . Although specific steps are shown in  FIG. 4 , in other embodiments, a method can have more or less steps than shown. The method steps discussed in this and other figures can be implemented in the shown order or combination, or in any other order or combination. 
     At various points, the application distributor  112  receives a request from a user to purchase an application ( 402 ). The purchase request can come from any user terminal with access to the application distributor  112 . As described above, the purchase request can include account information for the requesting user that can be used to facilitate the transaction, such as the user&#39;s account identifier. 
     In response to the purchase request, the application distributor  112  constructs an application proof of purchase receipt ( 404 ), such as the receipt  300  in  FIG. 3 . The application proof of purchase receipt can be unique to the transaction. For example, even if the user has previously purchased the application, the proof of purchase receipt associated with this purchase request will be different. However, in some configurations, the proof of purchase receipt can be unique to the user, application pair, instead of the transaction. After constructing the application proof of purchase receipt, the application distributor  112  creates an application bundle, based on the application purchase receipt and the application ( 406 ), and sends the application bundle to the requesting user ( 408 ). 
     After purchasing an application, it may be possible to use that application on multiple user terminals. To prevent a user from abusing this capability, an application developer and/or application distributor can institute a usage policy that limits the number of user terminals on which an application can be used at any one time. For example, suppose an application costs ten dollars. A user could purchase the application and then sell a copy of the application to nine of his friends for one dollar. Each of the ten users was then able to obtain a copy of the ten-dollar application for one dollar. In some cases, an application developer may be okay with this scenario; however, in other cases, such activity may prevent the developer from recouping their development costs. To curb such activity, a policy can be established to limit the number of copies to, say, five machines. One way of ensuring that a user only runs an application on a specified number of machines is to have the user authorize each machine on which he or she wants to use the application. 
     An authorization file, which can reside on the user&#39;s machine, can be used to facilitate user authorization.  FIG. 5  illustrates an exemplary authorization file  500 . The authorization file  500  can include an authorization file body  502 . The authorization file body  502  can include a unique machine identifier for the machine associated with the authorization file  500 . The unique machine identifier can be an identifier that can be linked to a user terminal. For example, the various hardware components in a computer can be associated with a unique identifier, such as a serial number. One or more of these serial numbers can be used to create a unique machine identifier. 
     The authorization file body  502  can also contain one or more unique account identifiers, e.g., DSid. The account identifiers contained in the authorization file  500  indicate the users who are authorized to use purchased applications on the machine. In some configurations, instead of including the plaintext DSid, the authorization file body  502  can include a unique representation of the DSid. For example, the unique representation can be a one-way representation of DSid, e.g., f(DSid). In some cases, the unique representation can be used to improve security of the receipt and/or user privacy. 
     In some configurations, an authorization file body  502  can include additional and/or alternative information. Furthermore, the organization of the information within the authorization file  500  can vary with the configuration of the system. 
     In some configurations, the authorization file  500  can be in plaintext, which would make it readable to any user that can understand the file layout. To prevent and/or detect unauthorized modification of the authorization file  500 , the authorization file  500  can include an authorization file signature  504 . The authorization file signature  504  can be any digital signature that can be used to detect unauthorized modification of the authorization file. For example, the application distributor  112  can use a cryptographic hash function to generate a digital signature of the authorization file body  502 . In some configurations, the application distributor  112  can use a public key system to generate the digital signature. In this case, the application distributor  112  uses its private key to generate the authorization file signature  504 . A user terminal, the application distributor, and/or any other device with access to the application distributor&#39;s public key can then verify the authorization file  500 . Alternatively, the application distributor  112  can use a private key system to generate the authorization file signature  504 . In this case, unless the application distributor  112  shares its private key, only the application distributor can verify the authorization file  500 . 
     An authorization request can be made to the application distributor or any other device responsible for authorizing the users in the system. The authorization file can be used to keep track of which users are authorized to run applications on a particular user terminal, while the server can maintain authorization records to keep track of how many machines and/or the exact machines that each user is authorized on. The authorization records on the server can be used to make sure a user is not authorized on more machines than allowed by the usage policy. 
       FIG. 6  illustrates an exemplary user authorization scenario  600 . To authorize a user on a machine, the server  606  receives the authorization file  602  and the user&#39;s unique account identifier  604 . The server  606  then checks the authorization records  608  to verify that the user is not already authorized on the maximum number of machines allowed under the usage policy. In this example, the user DSid 8  is only authorized on one machine, which is less than the limit, so the server  606  can authorize the user. To authorize the user, the server  606  updates the entry in the authorization records for the user to include the machine identifier in the authorization file  602 , i.e., M 1 . This yields the authorization records  610 . The server also updates the authorization file by adding the user&#39;s account number, i.e., f(DSid 8 ), and re-signing the file. The server  606  then returns the updated authorization file  612  to the user&#39;s machine. In some configurations, the server  606  can maintain other information in the authorization records. Other methods of authorization are also possible using all or part of these steps. 
     In some configurations, the usage policy can be static across all users and all applications, or the usage policy can be user-specific and/or application-specific. For example, a usage policy can be designed such that any user can be authorized to use any of the applications they purchased on up to five machines at any given time. However, the system can also be configured such that a usage policy can be specified for an individual application. For example, one application could allow users to use the application on 10 machines, while another application may only allow the user to use the application on 4 machines. To support a variable usage policy scheme the server  606  may need to store additional information in the authorization records. 
     In some configurations, user authorization can occur at the time the user purchases the application.  FIG. 7  illustrates an exemplary scenario  700  for authorization on purchase. In method  700 , the user terminal  102  makes a purchase request to the application distributor  112 . In addition to account information, such as the DSid, the purchase request can include an authorization file  706  that resides on the user terminal  102 . The application distributor  112  can create the application bundle  708  using the method  400  in  FIG. 4  and can perform the authorization method  600  in  FIG. 6  to update the authorization records and produce the authorization file  710 . The application distributor  112  can then send the application bundle and updated authorization file  710  to the requesting user terminal  102 . In some configurations, the application distributor  112  acts as an intermediary for the authorization request and simply passes the authorization request off to another device or server that will return the authorization file to the application distributor  112 . In some cases, the user is authorized on the user terminal  102  prior to making the purchase request. In this case, the application distributor  112  can either return the authorization file unchanged or not return the file at all. In some configurations, the user terminal can determine that the user is authorized on the machine without making an authorization request to the server. 
     In some cases, authorization on purchase may be unnecessary because the user has no intention of using the application on the machine from which he or she purchased the application. For example, a user may have a slow Internet connection at home, but a very fast connection at work. In some cases, the Internet connection speeds may not matter, but for large applications a slow network connection can prevent a user from purchasing a particular application. To improve the user&#39;s purchasing experience, the user may decide to purchase the application at work and then transfer the application to the user&#39;s home computer. For example, the user may transfer the application to a disk, e.g., CD-ROM, DVD, USB drive, etc., and then transfer the application to the home computer, or the user may establish a direct high-speed connection between the user&#39;s work computer and home computer, e.g., through an Ethernet connection. Furthermore, to allow the user to copy the application to more than one machine, authorization can occur when the user attempts to use the application. 
       FIG. 8  illustrates an exemplary scenario  800  for authorization on application launch. In this scenario, the user makes a purchase request from the user terminal  102 . The purchase request is sent to the application distributor  112  where application bundle  806  is prepared using method  400  in  FIG. 4 . The application bundle  806  is sent to the user terminal  102 . At some point, the application bundle  806  is copied to user terminal  104  where the user attempts to use the application. Upon launch of the application, the user terminal sends an authorization request to the server  606 . In some configurations, the server  606  and the application distributor  112  can be the same. However, in other cases, the server  606  and the application distributor  112  can be different. As part of the authorization request, the server  606  receives the authorization file  812  and the user&#39;s account identifier  814 . The server  606  performs the authorization method  600  in  FIG. 6  and returns the updated authorization file  816  to the user terminal  104 . Now that the user is authorized on the machine, the user can use the application. In some configurations, a user may already be authorized to use applications on the machine. In this case, no updates to the authorization file are required. Furthermore, in some cases, the user terminal determines that the user is authorized without making an authorization request to the server. 
     The user authorization scenario  600  in  FIG. 6  only prevents a user from being authorized to run applications on more than a specified number of machines. By incorporating the application proof of purchase receipt created at the time of purchase, application verification can enforce an application usage policy that limits the use of a particular application to a specified number of machines or instances at any given time. For example, the application can be limited to five separate instances in five different guest virtual machines that all reside on a single host physical machine. When a user purchases an application, an application purchase receipt is included with the application. To use a purchased application on a particular machine, the account identifier in the proof of purchase receipt must be authorized on the machine. As described above, each machine can maintain a single authorization file that can specify the machine identifier for the machine and all account identifiers of users authorized to run applications on the machine. If the account identifier in the proof of purchase receipt is contained in the authorization file, the application can be used on the machine. However, if the user associated with the application is not authorized on the machine, the user can be authorized using an authorization method such as method  600  in  FIG. 6 . Both the proof of purchase receipt and the authorization file can be verified to prevent unauthorized modification of the proof of purchase receipt and/or authorization file and ensure that the receipt belongs to the application and the authorization file belongs to the machine. 
     The exemplary application verification method  900  in  FIG. 9  can be used to enforce an application usage policy that is directed at limiting the purchasing user to a specified number of machines. The verification method  900  can use the application proof of purchase receipt  300  in  FIG. 3  and the authorization file  500  in  FIG. 5 . For the sake of clarity, method  900  is discussed in terms of an exemplary system  100  as shown in  FIG. 1 . Although specific steps are shown in  FIG. 9 , in other embodiments, a method can have more or less steps than shown. 
     The application verification method  900  can be used each time a user launches an application and can be performed locally by the machine on which the application resides. However, the system can also be configured such that application verification is performed less frequently, such as on the first launch of the application. Additionally, application verification can be performed by making a verification request to a server or it can be a combination of local and remote actions. 
     Upon application launch, the user terminal  102  receives a request to verify an application based on a proof of purchase receipt  300  and an authorization file  500  ( 902 ). As part of the application verification, the user terminal  102  can verify the proof of purchase receipt  300 , by first checking that the signature of the receipt is valid ( 904 ). If the signature is not valid, then it is likely that the receipt has been altered so the verification process is aborted and verification fails. If the signature is valid, the user terminal  102  checks if the application identifier in the receipt matches the identifier of the application being verified ( 906 ). If it does not match, verification fails. If the application identifier does match, the user terminal  102  checks if the application version number in the receipt matches the version number of the application being verified ( 908 ). If the version number does not match, the verification method fails, otherwise verification continues. 
     The verification method  900  can also include a verification of the authorization file  500 . To verify the authorization file  500 , the user terminal  102  checks if the signature on the file is valid ( 910 ). If the signature is not valid, then it is likely that the authorization file has been altered so the verification process is aborted and verification fails. If the signature is valid, the user terminal  102  checks if the machine identifier in the authorization file matches the identifier for the user terminal  102  ( 912 ). If it does not match, verification fails. If the machine identifier does match, the verification continues. 
     Depending on the configuration, steps  904 ,  906  and  908  can be performed before, after, or in parallel with steps  910  and  912 . Furthermore, steps  904 - 912  do not have to be performed at all, but by performing the steps a level of assurance can be gained that the files are unaltered and correspond with the application and machine. After verifying the receipt  300  and authorization file  500 . The user terminal  102  checks if the account number in the receipt, e.g., f(DSid), is in the authorization file ( 914 ). If so, the user who purchased the application is authorized on the machine, so the application can launch ( 916 ). If the user who purchased the application is not already authorized, the user terminal  102  can make an authorization request to the application distributor  112  ( 918 ). If the authorization request succeeds ( 920 ), the application can launch ( 916 ) otherwise verification fails. 
     In some configurations, the verification method  900  can occur inside of the application. In this case, the action taken upon a verification failure depends on the application developer. For example, upon verification failure, the application could quit. Alternatively, upon verification failure, the application could continue executing, but only limited functionality may be available. Additionally, depending on the configuration, the application may not be able to request authorization for the user. 
     Using the verification method  900  described above, the user associated with a purchased application can use the application on the number of machines specified in the usage policy. For example, if the maximum number of machines is five, the user can copy the application to five different machines and go through the authorization process on each machine. If the user wants to use the application on a 6th machine, the user has to de-authorize one of the already authorized machines. To do so, the user can send a “de-authorize” request from one of the authorized machines. Alternatively, in some configurations, the user can send a “de-authorize all” request from any machine, which will have the effect of de-authorizing all machines that the user was authorized on. After de-authorizing a machine, the user can go back to the 6th machine and authorize it. At this point, if the verification method  900  succeeds, the user can use the application. 
     In some cases, a user may attempt to circumvent the maximum machine usage policy. One way that a user may attempt to do this is as follows. Suppose the user associated with the purchased application is already authorized on the maximum number of machines, say five. To free up an authorization, the user de-authorizes a machine. However, prior to issuing the “de-authorize” request, the user makes a copy of the authorization file on the machine. After the de-authorization, the user copies the authorization file back into place. Now the machine thinks the user is authorized even though the user has been de-authorized. 
     To address this circumvention attack a de-authorization count field can be added to the application proof of purchase receipt and the authorization file. Additionally, a de-authorization count can also be maintained on the server.  FIG. 10  illustrates an exemplary proof of purchase receipt  1002  and authorization file  1004  with de-authorization count fields. In the authorization file  1004 , a separate de-authorization count can be associated with each authorized account identifier. Each time a user de-authorizes a machine, the de-authorization count on the server associated with the account identifier can be incremented. When a user purchases a new application, the de-authorization count in the authorization record associated with the user can be included in the application proof of purchase receipt. Additionally, when a user authorizes a machine, the de-authorization count associated with that account identifier can be included in the authorization file. 
     The de-authorization count can also be incorporated in the application verification method. When a user attempts to use an application, the verification method can perform all of the steps described in the verification method  900 . However, the verification method can also check that the de-authorization count in the receipt is less than or equal to the de-authorization count in the authorization file. If this check fails, the user can be prevented from using the application on that machine. 
       FIG. 11  illustrates an exemplary application verification method  1100  that uses the de-authorization counters. The verification method  1100  can use the application proof of purchase receipt  1002  and the authorization file  1004  in  FIG. 10 . For the sake of clarity, method  1100  is discussed in terms of an exemplary system such as is shown in  FIG. 1 . Although specific steps are shown in  FIG. 10 , in other embodiments, a method can have more or less steps than shown. 
     The application verification method  1100  can be used each time a user launches an application and can be performed locally by the machine on which the application resides. However, the system can also be configured such that application verification is performed less frequently, such as on the first launch of the application. Additionally, application verification can be performed by making a verification request to a server or it can be a combination of local and remote actions. 
     Upon application launch, the user terminal  102  receives a request to verify an application based on a proof of purchase receipt  1002  and an authorization file  1004  ( 1102 ). The user terminal  102  can then verify that the proof of purchase receipt  1002  and authorization file  1004  are valid using steps similar to  904 - 912  in  FIGS. 9  ( 1104  and  1106 ). If either validation step fails, the verification method aborts and the verification fails. Depending on the configuration, step  1104  can be performed before, after, or in parallel with step  1106 . Furthermore, steps  1104  and  1106  do not have to be performed at all, but by performing the steps a level of assurance can be gained that the files are unaltered and correspond with the application and machine. 
     After verifying the receipt  1002  and authorization file  1004 , the user terminal  102  checks if the account number in the receipt, e.g., f(DSid), is in the authorization file ( 1108 ). If so, the user who purchased the application is authorized on the machine and the verification can proceed to check the de-authorization counts. If the user who purchased the application is not already authorized, the user terminal  102  can make an authorization request to the application distributor  112  ( 1110 ). If the authorization request succeeds ( 1114 ), the user terminal  102  can proceed to check the de-authorization counts. 
     At step  1112 , the user terminal  102  verifies the de-authorization counts by checking that the de-authorization count in the receipt is less than or equal to the de-authorization count in the authorization associated with account identifier. If so, verification has succeeded and the user terminal  102  can launch the application ( 1116 ). If the de-authorization count verification fails, it is likely a de-authorization attack has occurred so the user is prevented from using the application on the machine. 
     As with the verification method  900 , verification method  1100  can be performed within the application. In this case, the action taken upon a verification failure depends on the application developer. For example, upon verification failure, the application could quit. Alternatively, upon verification failure, the application could continue executing, but only limited functionality may be available. Additionally, depending on the configuration, the application may not be able to request authorization for the user. 
       FIG. 12  illustrates an exemplary de-authorization counter usage scenario. In this scenario, the user with account identifier DSid 1  is currently authorized on five machines: M 1 -M 5 . The user also wants to be able to use applications on a sixth machine M 6 , but the usage policy limits the number of authorizations to five. This initial scenario set up is reflected in the authorization files for machines M 5  and M 6  and in authorization records on the server ( 1210 ). Machine M 5 &#39;s authorization file contains and entry for DSid 1  with an associated de-authorization count of zero. Machine M 6 &#39;s authorization file is empty. The authorization records on the server show that DSid 1  is authorized on machines M 1 -M 5  and the user has not de-authorized any machines. 
     In an attempt to use applications on a sixth machine M 6 , the user makes a copy of the authorization file on M 5  and then de-authorizes the machine. These actions are reflected in the authorization file on machine M 5  and the authorization records on the server ( 1220 ). Machine M 5 &#39;s authorization file is now empty. Additionally, the de-authorization count is increased to one and M 5  has been removed from the list of authorized machines in the authorization records on the server. 
     The user now authorizes machine M 6 . This action results in two changes, which are reflected in machines M 5  and M 6  and the server ( 1230 ). First, the authorization file on machine M 6  is updated to include DSid 1  with a de-authorization count of 1. Second, the authorization records on the server are updated to include machine M 6  in the list of authorized machines. 
     After the authorization, the user replaces the authorization file with the old authorization file and purchases an application. The changes are reflected in machines M 5  and M 6  and the server ( 1240 ). The de-authorization count in the proof of purchase receipt is 1. When the user attempts to use the application on machine M 5 , the machine can verify the application using verification method  1100 . Since the de-authorization count in the proof of purchase receipt is greater than the de-authorization count in the authorization file, the verification method  1100  will fail at step  1112 . The user can then be prevented from using the application on the machine. 
     The disclosure now turns to a discussion of a general-purpose computing device. All or part of the components shown in  FIG. 13  and discussed below can be used to implement the various devices and infrastructure elements discussed above. With reference to  FIG. 13 , an exemplary system  1300  includes a general-purpose computing device  1300 , including a processing unit (CPU or processor)  1320  and a system bus  1310  that couples various system components including the system memory  1330  such as read only memory (ROM)  1340  and random access memory (RAM)  1350  to the processor  1320 . The system  1300  can include a cache  1322  of high speed memory connected directly with, in close proximity to, or integrated as part of the processor  1320 . The system  1300  copies data from the memory  1330  and/or the storage device  1360  to the cache  1322  for quick access by the processor  1320 . In this way, the cache  1322  provides a performance boost that avoids processor  1320  delays while waiting for data. These and other modules can be configured to control the processor  1320  to perform various actions. Other system memory  1330  may be available for use as well. The memory  1330  can include multiple different types of memory with different performance characteristics. It can be appreciated that the disclosure may operate on a computing device  1300  with more than one processor  1320  or on a group or cluster of computing devices networked together to provide greater processing capability. The processor  1320  can include any general purpose processor and a hardware module or software module, such as module  1   1362 , module  2   1364 , and module  3   1366  stored in storage device  1360 , configured to control the processor  1320  as well as a special-purpose processor where software instructions are incorporated into the actual processor design. The processor  1320  may essentially be a completely self-contained computing system, containing multiple cores or processors, a bus, memory controller, cache, etc. A multi-core processor may be symmetric or asymmetric. 
     The system bus  1310  may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. A basic input/output (BIOS) stored in ROM  1340  or the like, may provide the basic routine that helps to transfer information between elements within the computing device  1300 , such as during start-up. The computing device  1300  further includes storage devices  1360  such as a hard disk drive, a magnetic disk drive, an optical disk drive, tape drive or the like. The storage device  1360  can include software modules  1362 ,  1364 ,  1366  for controlling the processor  1320 . Other hardware or software modules are contemplated. The storage device  1360  is connected to the system bus  1310  by a drive interface. The drives and the associated computer readable storage media provide nonvolatile storage of computer readable instructions, data structures, program modules and other data for the computing device  1300 . In one aspect, a hardware module that performs a particular function includes the software component stored in a non-transitory computer-readable medium in connection with the necessary hardware components, such as the processor  1320 , bus  1310 , output device  1370 , and so forth, to carry out the function. The basic components are known to those of skill in the art and appropriate variations are contemplated depending on the type of device, such as whether the device  1300  is a small, handheld computing device, a desktop computer, or a computer server. 
     Although the exemplary embodiment described herein employs the hard disk  1360 , it should be appreciated by those skilled in the art that other types of computer readable media which can store data that are accessible by a computer, such as magnetic cassettes, flash memory cards, digital versatile disks, cartridges, random access memories (RAMs)  1350 , read only memory (ROM)  1340 , a cable or wireless signal containing a bit stream and the like, may also be used in the exemplary operating environment. Non-transitory computer-readable storage media expressly exclude media such as energy, carrier signals, electromagnetic waves, and signals per se. 
     To enable user interaction with the computing device  1300 , an input device  1390  represents any number of input mechanisms, such as a microphone for speech, a touch-sensitive screen for gesture or graphical input, keyboard, mouse, motion input, speech and so forth. An output device  1370  can also be one or more of a number of output mechanisms known to those of skill in the art. In some instances, multimodal systems enable a user to provide multiple types of input to communicate with the computing device  1300 . The communications interface  1380  generally governs and manages the user input and system output. There is no restriction on operating on any particular hardware arrangement and therefore the basic features here may easily be substituted for improved hardware or firmware arrangements as they are developed. 
     For clarity of explanation, the illustrative system embodiment is presented as including individual functional blocks including functional blocks labeled as a “processor” or processor  1320 . The functions these blocks represent may be provided through the use of either shared or dedicated hardware, including, but not limited to, hardware capable of executing software and hardware, such as a processor  1320 , that is purpose-built to operate as an equivalent to software executing on a general purpose processor. For example the functions of one or more processors presented in  FIG. 13  may be provided by a single shared processor or multiple processors. (Use of the term “processor” should not be construed to refer exclusively to hardware capable of executing software.) Illustrative embodiments may include microprocessor and/or digital signal processor (DSP) hardware, read-only memory (ROM)  1340  for storing software performing the operations discussed below, and random access memory (RAM)  1350  for storing results. Very large scale integration (VLSI) hardware embodiments, as well as custom VLSI circuitry in combination with a general purpose DSP circuit, may also be provided. 
     The logical operations of the various embodiments are implemented as: (1) a sequence of computer implemented steps, operations, or procedures running on a programmable circuit within a general use computer, (2) a sequence of computer implemented steps, operations, or procedures running on a specific-use programmable circuit; and/or (3) interconnected machine modules or program engines within the programmable circuits. The system  1300  shown in  FIG. 13  can practice all or part of the recited methods, can be a part of the recited systems, and/or can operate according to instructions in the recited non-transitory computer-readable storage media. Such logical operations can be implemented as modules configured to control the processor  1320  to perform particular functions according to the programming of the module. For example,  FIG. 13  illustrates three modules Mod 1   1362 , Mod 2   1364  and Mod 3   1366  which are modules controlling the processor  1320  to perform particular steps or a series of steps. These modules may be stored on the storage device  1360  and loaded into RAM  1350  or memory  1330  at runtime or may be stored as would be known in the art in other computer-readable memory locations. 
     Embodiments within the scope of the present disclosure may also include tangible and/or non-transitory computer-readable storage media for carrying or having computer-executable instructions or data structures stored thereon. Such non-transitory computer-readable storage media can be any available media that can be accessed by a general purpose or special purpose computer, including the functional design of any special purpose processor as discussed above. By way of example, and not limitation, such non-transitory computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code means in the form of computer-executable instructions, data structures, or processor chip design. When information is transferred or provided over a network or another communications connection (either hardwired, wireless, or combination thereof) to a computer, the computer properly views the connection as a computer-readable medium. Thus, any such connection is properly termed a computer-readable medium. Combinations of the above should also be included within the scope of the computer-readable media. 
     Computer-executable instructions include, for example, instructions and data which cause a general purpose computer, special purpose computer, or special purpose processing device to perform a certain function or group of functions. Computer-executable instructions also include program modules that are executed by computers in stand-alone or network environments. Generally, program modules include routines, programs, components, data structures, objects, and the functions inherent in the design of special-purpose processors, etc. that perform particular tasks or implement particular abstract data types. Computer-executable instructions, associated data structures, and program modules represent examples of the program code means for executing steps of the methods disclosed herein. The particular sequence of such executable instructions or associated data structures represents examples of corresponding acts for implementing the functions described in such steps. 
     Those of skill in the art will appreciate that other embodiments of the disclosure may be practiced in network computing environments with many types of computer system configurations, including personal computers, hand-held devices, multi-processor systems, microprocessor-based or programmable consumer electronics, network PCs, minicomputers, mainframe computers, and the like. Embodiments may also be practiced in distributed computing environments where tasks are performed by local and remote processing devices that are linked (either by hardwired links, wireless links, or by a combination thereof) through a communications network. In a distributed computing environment, program modules may be located in both local and remote memory storage devices. 
     The various embodiments described above are provided by way of illustration only and should not be construed to limit the scope of the disclosure. Those skilled in the art will readily recognize various modifications and changes that may be made to the principles described herein without following the example embodiments and applications illustrated and described herein, and without departing from the spirit and scope of the disclosure.

Metadata:
Filing Date: 20181031
Publication Date: 20221018
Grant Date: 20221018
Priority Date: 20101019
Inventors: CIUDAD, JEAN-PIERRE
FARRUGIA, AUGUSTIN J.
M'RAIHI, DAVID
TOUBLET, BERTRAND MOLLINIER
FASOLI, GIANPAOLO
SULLIVAN, NICHOLAS T.
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F21/105", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F21/105", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06Q30/0641", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06Q30/0601", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F21/10", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06Q30/0601", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06Q30/0641", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06Q30/0601", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F21/105", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06Q30/0641", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 44872612