Abstract:
A method and computer system for providing access to computer resources on a computer system and includes generating a token containing encrypted user information including credit, authorization, and authentication information. A request is initiated to open an encrypted computer resource stored on the computer system, and execution of a remote application manager component on the computer system is also initiated. The remote application manager component decrypts the token and authenticates a user using authentication information stored in the token. Whether the user is authorized and has sufficient credit are then verified. When the user is approved, the requested computer resource is decrypted and opened. Use of the computer resource is monitored to determine whether the user has sufficient credit to continue using the computer resource. A notification is provided when the monitored usage of the opened computer resource has exceeded the credit.

Description:
TECHNICAL FIELD 
   The present invention relates generally to computer systems, and more specifically to providing access to computer resources over a computer network such as the Internet. 
   BACKGROUND OF THE INVENTION 
   The architecture of computer networks has changed dramatically over the last several decades. In the seventies and early eighties, probably the most prevalent architecture was the mainframe architecture in which a very powerful mainframe computer contained all processing and storage power and users accessed the mainframe via so called “dumb” terminals, which had no processing power and acted merely as user interfaces to the mainframe. The mainframe architecture is prone to system failures because all processing power is located in the powerful mainframe computer, and while the mainframe computer is down no users can access the system. In the eighties, advancements in semiconductor technology enabled significant processing power to be placed on a user&#39;s desktop in the form of a personal computer. Consequently, the predominant computer network architecture defaulted into a distributed architecture, with a number of personal computers being interconnected via a communications network, such as a local area network. Under this type of architecture, each personal computer was able to share resources with the other computers, but many resources, such as application programs, were primarily stored and run independently on each personal computer, due, in part, to bandwidth limitations of communicating over the network. 
   In today&#39;s computing environment, the Internet forms part of a Global Communications Network that interconnects millions of computers via the client-server network architecture. In the client-server architecture, servers are powerful computers dedicated to managing network resources, and clients are personal computers or workstations that run application programs and rely on servers for computer resources such as files and even processing power. The client-server architecture has become a viable network architecture due in part to the dramatically increased bandwidth provided by the communications infrastructure forming the backbone of the Internet, as will be appreciated by those skilled in the art. The distributed processing power between the client and server systems has led to a myriad of third parties that provide software services to a number of users over the Internet or other wide area network. These third parties are known as Application Service Providers (“ASPs”) and they allow users to access software services provided by the ASPs by accessing a server maintained by the ASP over a suitable communications network.  FIG. 1  is a functional block diagram illustrating a conventional ASP system  100  including a client computer system  102  that accesses an ASP server computer system  104  over a communications network  106 , which may be the Internet or other suitable communications network. The client computer system  102  accesses the server computer system  104  to utilize the specific software services provided by the server computer system, which may be simply downloading a desired application program or supplying input to an application running on the server computer system to obtain desired data, as will be described in more detail below. 
   In the example of  FIG. 1 , the client computer system  102  includes a browser  108  that sends Hypertext Transfer Protocol (“HTTP”) requests to the server computer system  104  over the communications network  106 . In response to the applied requests, a server engine  110  on the system  104  processes the requests and provides files to the client computer system  102  such as Web pages  112  and client application programs  114 . The client application programs  114  are shown as including a number of individual application programs AP1-APN, each of which may be independently selected and transferred to the client computer system  102 . The application programs  114  are an example of one type of computer resource that an ASP provider may make available to users, as will be appreciated by those skilled in the art. The Web pages  112  function as the client interface to the ASP server computer system and allow the client computer system  102  to, among other things, select which ones of application programs  114  are to be transferred. 
   In operation, a user of the client computer system  102  accesses the ASP server computer system  104  and typically provides a request that includes various user information, such as user name, credit information, and which ones of the client application programs  114  the user desires to access. The server engine  110  processes the request, which includes verifying the user&#39;s credit, and thereafter transfers the selected application programs  114  to the client computer system  102 . The user of the client computer system  102  thereafter utilizes the transferred application programs  114  as desired. 
   Depending on the type of service been provided by the ASP server computer system  104 , the transferred application programs  114  may correspond to either the entire executable application program including all required system files, such as any required dynamic link library files, or may be an application “stub” or module containing only a portion of the application. When the entire executable application program  114  is transferred, the user simply opens this program as he would any other programs stored on the system  102  and need not be connected to the server computer system  104  when using the application program. This situation may be termed a broken-connection mode of operation because the client computer system  102  and server computer system  104  are not communicating when the application program  114  is being run. In contrast, when an application module is transferred to the client computer system  102 , upon opening this module the application is initiated and the server computer system  104  is contacted and thereafter communicates with the client computer system to execute the application program. This situation may be termed a continuous-connection mode of operation because the client computer system  102  and server computer system  104  are communicating when the application program  114  is being run. 
   The user of the client computer system  102  must, of course, pay for the application programs  114  provided by the server computer system  104 . Typically, the user pays for the application programs  114  in one of two ways. In the broken-connection situation, a user typically pays as he goes, meaning that the user simply pays for each application program  114  downloaded to the client computer system  102 . In the continuous-connection situation, the user typically pays via a subscription agreement, allowing the user to pay a periodic subscription fee and obtain access to the services provided by the ASP server computer system  104 . A user is typically assigned a username and password, which the user supplies to gain access to the application programs  114  corresponding to his subscription agreement. 
   Each of the broken-connection and the continuous-connection situations has drawbacks, both from the user&#39;s and ASP&#39;s perspectives. When a user downloads an application program  114  to the client computer system  102 , the user may thereafter use the program on multiple computer systems and provide copies of the program to other users. While the terms of the license under which the user agrees to use the application program  114  may proscribe such conduct, the user may nonetheless take such action. In the continuous-connection environment, the user must connect to the server computer system  104  to run the selected application program  114 , and this connection can dramatically slow the operation of the program, such as when the server computer system  104  has a large number of client computer systems  102  requesting service. Moreover, although a subscription agreement may be limited to a single user and a single machine, a user may provide his password to others, enabling other users to access the computer resources. 
   There is a need for providing users access to computer resources offered by ASPs that overcomes at least some of the shortcomings of the existing ASP systems. 
   SUMMARY OF THE INVENTION 
   According to one aspect of the present invention, a method for providing access to computer resources on a computer system includes generating a token containing encrypted user information including credit, authorization, and authentication information. A request is initiated to open an encrypted computer resource stored on the computer system, and execution of a remote application manager component on the computer system is also initiated. Under the control of the remote application manager component, the token is decrypted and a user of the computer system is authenticated using authentication information stored in the token. Whether the user is authorized to use the requested computer resource using authorization information stored in the token is then verified, as is whether the user has sufficient credit contained in the token to use the requested computer resource using credit information stored in the token. When the user is authenticated, authorized, and has sufficient credit, the requested computer resource is decrypted and opened. Use of the computer resource is then monitored to determine whether the user has sufficient credit to continue using the computer resource. A notification is provided when the monitored usage of the opened computer resource has exceeded the credit. The computer system on which the above method is executed may be a client system. 
   According to another aspect of the present invention, a server system receives client requests from client computers, such client requests including authorization, authentication, and credit information, and verifies credit information contained in such requests. When the credit of a user is verified, the server system generates the token containing the associated user information. The server system also selects computer resources using information contained in the client requests and encrypts each selected computer resource. The server system transfers to the client system the token and the encrypted selected computer resources along with the remote application manager component. The server system may thereafter update credit information and authorization information in response to client request from the client system, and provide the client system with an updated token and updated selection of computer resources. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a functional block diagram of a conventional client-server system in which an application service provider server supplies services to the client system. 
       FIG. 2  is a functional block diagram illustrating a client-server system in which an application service provider server supplies services to client systems according to one embodiment of the present invention. 
       FIG. 3  is a diagram illustrating one embodiment of the token of  FIG. 2 . 
       FIG. 4  is a flow diagram illustrating in the operation of the remote application manager component of  FIG. 2  in more detail. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 2  is a functional block diagram illustrating an ASP system  200  according to one embodiment of the present invention. The ASP system  200  includes an ASP server computer system  202  and client computer systems  204  and  206  that allow an Application Service Provider operating the server computer system to provide computer resources to users in both the broken-connection and continuous-connection environments with reduced concern of unauthorized use and transfer of such computer resources, as will be described in more detail below. In the following description, certain details are set forth to provide a sufficient understanding of the invention. However, it will be clear to one skilled in the art that the invention may be practiced without these particular details. In other instances, well-known components, concepts, and details such as timing and other common software operations have not been shown in detail in order to avoid unnecessarily obscuring the invention. 
   The client computer systems  204  and  206  communicate with the server computer system  202  over communications links  208  and  210 , respectively. The communications links  208  and  210  are illustrated separately to depict a continuous-connection environment via the link  208  and a broken-connection environment via the link  210 , and each link corresponds to any of a variety of communications networks, such as the Internet, Local Area Networks, Wide Area Networks, a wireless network using the Wireless Application Protocol, and the like, as will be appreciated by those skilled in the art. 
   The server computer system  202  includes a client interface component  212  that processes requests received from the client computer systems  204 ,  206  and communicates with other components on the server computer system to provide the client computer systems with responses to such requests. An accounting and billing component  214  receives credit and billing information from the client interface component  212  and processes such information to verify a user&#39;s credit and bill the user for his use of the selected computer resources. A plurality of application programs  216  are stored on the server computer system  202 , and correspond to one type of computer resource that may be supplied to the client computer systems  204 ,  206 . The client interface component  212  selects particular ones of application programs  216  in response to corresponding client requests, encrypts the selected application programs, and provides the encrypted application programs to the client computer systems  204 ,  206 . A token generation component  218  receives user information from the client interface component  212  and generates a token  220  using this information, where the token corresponds to a binary file containing encrypted user information, as will be described in more detail below. A key generation component  222  is responsible for generating encryption keys for use by the client interface component  212  in encrypting application programs  216  and the token generation component  218  in encrypting information. The key generation component  222  may utilize any of a variety of encryption methodologies in generating the encryption keys, and in one embodiment utilizes the Public Key encryption methodology to obtain public-private key pairs. 
   Each of the client computer systems  204  and  206  includes a number of components that have been downloaded from the server computer system  202 . The client computer system  204  includes the token  220  and a plurality of application modules AM1-AMN, each application module being an encrypted file corresponding to a selected application program  216  on the server computer system  202 . A remote application manager component  224  operates as a supervisory component to decrypt the token  220  and verify that a user is permitted to use a particular application module AM1-AMN, and thereafter decrypts the corresponding application module to enable the user to utilize the application module, as will be discussed in more detail below. The client computer system  204  is also shown as including a phantom application  226 , which corresponds to an object which, when opened, initiates execution of corresponding application program stored on the server computer system  202 . The phantom application  226  is thus similar to the application modules AM1-AMN except that no portion of the application program is actually stored on the client computer system  204 . The client computer system  204  may contain any combination of application modules AM1-AMN and phantom applications  226 . 
   The client computer system  206  also includes the token  220  and remote application manager component  224 , along with a plurality of application programs AP1-APN, each application program being an encrypted file corresponding to a selected program  216  on the server computer system  202 . Each application program AP1-APN is a complete executable program including any necessary system files, as previously discussed with reference to  FIG. 1 . The remote application manager component  224  once again operates as a supervisory component to decrypt the token  220  and verify that a user should be permitted to use a particular application program AP1-APN, and thereafter decrypts the corresponding application program to enable the user of the client computer system  206  to utilize the application program. 
   In one embodiment, the client computer system  206  includes a card reader  226  that is adapted to receive a “smart card”  228  on which the token  220  is stored. The card reader  226  reads the token  220  stored on the smart card  228  and provides the token to the remote application manager component  224 . The smart card  228  may be any type of compact card on which the token  220  may be stored, such as a true smart card containing embedded intelligence and memory, a credit card, an ATM card, and the like. The use of the smart card  228  enables a user to utilize multiple client computer systems to access the server computer system  202 , and also provides added security in that presumably only the authorized user will be in possession of the smart card. Although the card reader  226  and smart card  228  are shown connected to the client computer system  206 , they could also be utilized in the client computer system  204 . 
   The specific type of user information stored in the token  220  aids in understanding the overall operation of the ASP system  200 , and thus, before describing such overall operation, the token  220  will be described in more detail with reference to  FIG. 3 .  FIG. 3  illustrates one embodiment of the token  220  which, as previously mentioned, corresponds to an encrypted binary file containing a variety of user information. In the example of  FIG. 3 , the user information is stored in a number of fields within the token  220 . Starting from the leftmost side of the token  220 , the token includes a plurality of authentication fields  300  that are utilized to ensure that only a particular user may access the associated computer resources. As will be understood by those skilled in the art, authentication is a process of identifying an individual to ensure that an individual is who he claims to be, and this is to be distinguished from authorization, which is a process of granting individuals access to specific computer resources based on their identity (i.e., their authentication). 
   In the embodiment of  FIG. 3 , the first authentication field  300  is a hardware tag field  302  containing information about the specific client computer system  204 ,  206  on which the associated computer resources may be utilized. The hardware tag field  302  may, for example, correspond to a processor identification number of the microprocessor running on the client computer system  204 ,  206 . Recall that the token generation component  218  on the server computer system  202  generates the token  220 , and thus during initialization appropriate information for generating this tag is transferred from the client computer system  204 ,  206  to the server computer system. The second authentication field  300  is a user identification field  304  containing information such as a user&#39;s name, address, telephone number, and so on, to provide additional information for authenticating the user. The final illustrated authentication field  300  is a user Pretty Good Privacy (“PGP”) key  306  that references information contained on the server computer system  202  and in this way provides further user authentication since even if someone were to obtain the information in the fields  302 ,  304  they should would not typically know the PGP key  306 . The PGP technique for encrypting messages is based on the public-key method and will be understood by those skilled in the art. 
   A maintenance field  308  includes a user timestamp  310  corresponding to the time on the client computer system  204 ,  206  when the token  220  was generated. A server timestamp  312  stores the time on the server computer system  202  when the token  220  was generated. These timestamps  310 ,  312  ensure that the duration for which a user accesses a computer resource may be accurately tracked. An authorization field  314  includes an application identification field  316  that includes an application identification number for each application program the user is authorized to use. The application identification number is a unique number associated with each application program, as will be appreciated by those skilled in the art. An application authorization level field  318  stores information regarding particular authorization levels for each authorized application (i.e., each application identification stored in the field  312 ). Each authorized application may have a number of different authorization levels, and which authorization level a particular user has is stored in the field  318 . 
   An accounting field  320  includes a use credit field  322  containing a value corresponding to the time for which a user may utilize the associated computer resources, and a use value field  324  corresponding to the time for which the user has actually utilized the computer resources. The difference between the fields  322  and  324  yields the time remaining for the user to utilize the computer resources. The fields  322 ,  324  may contain values corresponding to different ways of measuring a user&#39;s use of the computer resources. For example, instead of the duration for which the resource is used, the fields  322 ,  324  could include integer values, with the field  322  having a value indicating how many times a user is allowed to access the computer resource and the field  324  indicating how many times he has accessed the resource. In this way, the number of times the user may access the computer resource is limited, regardless of how long he accesses the resource each time. Other methods for measuring a user&#39;s use of the computer resource may also be utilized, as will be appreciated by those skilled in the art. The token  220  may further include additional fields  326  containing various other information such as error detection and correction fields, as will be understood by those skilled in the art. 
   The overall operation of the ASP system  200  will now be described in more detail. Initially, the client computer systems  204 ,  206  contact the server computer system  202  to establish service with the Application Service Provider. In the following example, it is assumed the client computer system  206  has contacted the server computer system  202 . The client interface component  212  handles this interface with the client computer system  206 , and may, for example, provide Web pages to the client computer systems allowing users to supply billing, credit, and personal information, as well as information about the computer resources the user desires to access, in addition to any other information the server computer system  202  desires to collect. The client interface component  212  thereafter supplies billing and credit information to the accounting in billing component  214  which, in turn, verifies the user&#39;s credit and establishes billing records. If the user&#39;s credit is declined, the component  214  notifies the client interface component  212 , which then notifies the client computer system  206 . The component  214  similarly notifies the client interface component  212  when the user&#39;s credit is approved, and the following discussion assumes the credit has been approved. 
   The client interface component  212  supplies the user information to be contained in the token  220  to the token generation component  218 , and activates the key generation component  222  to generate an encryption key to be utilized for the client computer system  206  being processed. The token generation component  218  thereafter encrypts the user information received from the client interface component  212  using the encryption key to thereby generate the token  220 . The client interface component  212  uses the key to encrypt the application programs  216  corresponding to the selected application programs contained in the supplied user information. At this point, the client interface component  212  transfers the token  220 , the encrypted application programs  216  (designated application programs AP1-APN on the client computer system  206 ), and the remote application manager component  224  to the client computer system  206 . 
   When the user of the client computer system  206  attempts to open one of the transferred application programs AP1-APN, the remote application manager  224  operates in combination with the token  220  and the selected application program to provide the user access to the selected program. The process executed by the remote application manager component  224  will be described in more detail with reference to the flow diagram of  FIG. 4 . In step  400 , the user attempts to open the selected application program AP1-APN, which initiates execution of the remote application manager  224  and the process proceeds immediately to step  402 . In step  402 , the process determines whether the selected application program is loaded on the client computer system  206 . The Application Service Provider may load menus onto the client computer system  206  during the initialization process, and such menus may indicate all application programs AP1-APN provided by the Application Service Provider, regardless of whether the client computer system  206  is authorized to use such programs. When the determination in step  402  is negative, the process goes to step  404 , contacts the server computer system  202 , and steps the user through a process by which the user may gain access to the selected application program AP1-APN. This process would include the server computer system  202  transferring the encrypted application program to client computer system  206 . 
   Once step  404  is complete or if the determination in step  402  is positive, the process goes to step  406  and decrypts the token  220 . The process then goes to step  408  and examines the contents of the decrypted token component  224  to determine whether the selected application is authorized for use. When the determination in step  408  is positive, the process goes immediately to step  410  and decrypts and executes the selected application program. From step  410 , the process goes to step  412  and monitors the use of the selected application program. The process then goes to step  414  and determines whether the credit contained in the token  220  has expired. When the determination in step  414  is negative, the process proceeds to step  416  and determines whether the user has indicated a desire to stop running the selected application program. When the determination in step  416  is negative, the process goes back to step  412  and continues executing steps  412  and  414  to monitor the use of the selected application program AP1-APN and ensure that the user has sufficient credit to continue using the program. When the determination in step  416  is positive, indicating the user desires to stop running the selected application program, the process goes immediately to step  418  and the selected application program is once again encrypted along with the token  220 . From step  418  the process goes to step  420  and terminates. 
   When the determination in step  414  is positive, this indicates the user&#39;s credit contained in the token  220  has expired and the process goes to step  422  and warns the user to save his work. From step  422 , the process goes to step  424  and determines whether the user wishes to continue running the selected application program AP1-APN. When the determination in step  424  is negative, the process goes immediately step  418  and encrypts the selected application program and the token  220 , and then goes to step  420  terminates. When the determination in step  424  is positive, the process goes to step  426  and contacts the server computer system  202  to obtain additional credit for the user. Once the server computer system  202  has been contacted, the process goes to step  428  and determines whether the user has sufficient credit. When the process arrives at step  428  in this manner, the inquiry in step  428  is necessarily negative and the process goes immediately step  430 . In step  430 , the user is presented with a billing screen and provides required information to obtain additional credit. 
   From step  430 , the process goes to step  432  and supplies the information entered in step  430  to the server computer system  202 . From step  432 , the process goes to step  434  and determines whether the user&#39;s credit has been approved or declined by the server computer system  202 . When the determination in step  434  is negative, the users credit has been declined and the process goes immediately to step  420  and terminates. When the determination in step  434  is positive, the user&#39;s credit has been approved and the process goes to step  436  and a new token  220  is received from the server computer system  202 . The new token  220  contains updated credit information so that the user may access the desired application programs AP1-APN. From step  436 , the process goes back to step  406 . As indicated in  FIG. 4  in step  436 , the new token  220  may also included updated authorization information, which occurs when the process arrives at step  436  via a different route, as will now be described in more detail. 
   Going back to step  408 , when the determination in step  408  is negative the selected application program AP1-APN is not authorized for use. As a result, the process goes to step  438  and contacts the server computer system  202  in order to obtain authorization for the selected application program AP1-APN. In step  438 , the user will supply any required information to obtain access to the selected application program AP1-APN. From step  438 , the process goes to step  428  and determines whether the user has sufficient credit. If the determination in step  428  is positive, the process goes to step  436  and receives a new token from the server computer system  202 . It should be noted that when the process arrives at the step  436  via the determination in step  408  being negative and the determination in step  428  being positive, the new token  220  received in step  436  will include only updated authorization information. Conversely, when the process arrives at step  436  via steps  426  and  428 , the new token  220  received in step  436  will include only updated credit information. When the process arrives at the step  436  via the step  434 , the new token  220  may include both updated credit and authorization information. 
   With the ASP system  200 , an Application Service Provider can provide application programs for certain periods of time in both broken-connection and continuous-connection environments. Moreover, with the system  200  the versions of application programs being run by users may be conveniently updated each time the client computer system  204 ,  206  contacts the server computer system  202  to obtain additional credit. The system  200  also provides added security for Application Service Providers because unauthorized copies of the application programs may not be made, and users may be limited to a particular client computer system  204 ,  206  on which they can use the selected application programs. In the embodiment where the token  220  is contained on a smart card  228 , each user also realizes added security in preventing unauthorized use of the application programs since the smart card is required to access to such programs. 
   It is to be understood that even though various embodiments and advantages of the present invention have been set forth in the foregoing description, the above disclosure is illustrative only, and changes may be made in detail, and yet remain within the broad principles of the invention. For example, although the components described above would typically be implemented in software on suitable processing circuitry, where appropriate such components may be also be implemented using either digital or analog circuitry, or a combination of both. Therefore, the present invention is to be limited only by the appended claims.