Patent Publication Number: US-7219231-B2

Title: Extensible authentication system and method

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is related to co-pending U.S. Patent Application entitled “Parameter Verification in an Authentication System and Method”, accorded Ser. No. 10/060,620, filed on even date herewith, and is now U.S. Pat. No. 7,107,615. 
     TECHNICAL FIELD 
     The present invention is generally related to the field of authentication and, more particularly, is related to an extensible authentication system and method. 
     BACKGROUND OF THE INVENTION 
     Multifunction peripherals have become more and more common in the workplace and in the home. Typical multifunction peripherals often combine the functions of printing, faxing, scanning, and copying into a single device or system. Previously, offices may have had to purchase a printer for computers to print, a facsimile machine to transmit and receive faxes, a scanner to scan documents, and a copy machine to make copies. Now all of these functions are being combined in a single device to save workspace and provide significant cost savings and efficiency. In addition, some multifunction peripherals may provide digital sending capability that enables users to scan a document into digital form and then send the resulting digital document. 
     While a single multifunction peripheral may provide many different functions, it may not be the case that all individuals should have access to all of the capabilities thereof. In some cases, specific individuals may be provided with access to specific functions using some sort of security or authentication routine that limits access to specific functions to specified users. However, as more and more different functions are integrated into multifunction peripherals or any other machine that limits access to specific functions in a similar manner, the security and/or authentication systems used with such devices have to be restructured in order to limit access to such new functionality. This results in inefficiency and additional cost to adapt previous security and/or authentication systems for new functions on a device of restricted use. 
     SUMMARY OF THE INVENTION 
     In light of the foregoing, the present invention provides for a system, method, and a program embodied on a computer readable medium to perform authentication tasks. In one embodiment, the system comprises a number of authentication agents, each of the authentication agents authenticating at least one user parameter by performing at least one authentication task. The authentication task may or may not be unique with respect to the remaining ones of the authentication agents. The system also includes an authentication manager that requests each of the authentication agents to authenticate an unauthenticated user parameter. 
     In another embodiment, the present invention provides for a method for authentication that comprises the steps of providing for a number of authentication agents, each of the authentication agents being configured to perform at least one authentication task, requesting each of the authentication agents to authenticate an unauthenticated user parameter, and, obtaining a response from each of the authentication agents indicating whether the unauthenticated user parameter has been authenticated. 
     In still another embodiment, the present invention provides for a computer program embodied on a computer readable medium for performing authentication. In this regard, the program comprises code that embodies a number of authentication agents, each of the authentication agents authenticating at least one user parameter by performing at least one authentication task, and, code that embodies an authentication manager that requests each of the authentication agents to authenticate an unauthenticated user parameter. 
     Other features and advantages of the present invention will become apparent to a person with ordinary skill in the art in view of the following drawings and detailed description. It is intended that all such additional features and advantages be included herein within the scope of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention can be understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Also, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is a drawing of a multifunction peripheral that employs an authentication system according to an embodiment of the present invention; 
         FIG. 2  is a block diagram of the authentication system employed in the multifunction peripheral of  FIG. 1 ; 
         FIG. 3  is a block diagram of an authentication manager included in the authentication system of  FIG. 2 ; 
         FIG. 4  is a block diagram of an authentication agent included in the authentication system of  FIG. 2 ; 
         FIG. 5  is a flow chart of a “Request Authentication” method implemented in the authentication manager of  FIG. 3 ; and 
         FIG. 6  is a flow chart of an “Authenticate” method implemented in the authentication agent of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to  FIG. 1 , shown is a multi-function peripheral  103  according to an embodiment of the present invention. The multi-function peripheral  103  is a device that combines the operations of several other devices such as, for example, a copy machine, a scanner, a printer, a digital sender, and other devices. It may be the case that access to the various functions performed by the multi-function peripheral  103  is to be restricted to various individuals. The multi-function peripheral  103  includes an authentication system to verify that a user is whom they say they are in order to provide access to the functions of the multi-function peripheral  103  to which that individual is entitled. 
     In this respect, the multi-function peripheral  103  includes a processor  113  and a memory  116 , both of which are coupled to a local interface  119 . The local interface  119  may be, for example, a data bus with an accompanying control/address bus as can be appreciated by those with ordinary skill in the art. The processor  113 , memory  116 , and the local interface  119  make up a processor circuit that is generally known by those with ordinary skill in the art. The multi-function peripheral  103  may also include one or more display devices  123  and one or more user input devices  126 . The display device  123  is coupled to the local interface  119  by virtue of the display interface  129 . Correspondingly, the user input device  123  is coupled to the local interface  119  through one or more input interfaces  133 . In this respect, the display interface  129  and the input interface  133  may comprise, for example, appropriate input/output cards or other such devices as are generally known by those with ordinary skill in the art. 
     The multifunction peripheral  103  may also include a number of components that are employed to perform the various functions of copying, scanning, printing, digital sending and other functions. Such components may include, for example, paper path hardware to guide paper during the performance of the various functions, a printing assembly, scanning sensors and other scanning hardware, copying hardware, and other components. Such components are generally known by those with ordinary skill in the art and not discussed herein in detail. 
     The input devices may comprise, for example, a keyboard, keypad, touch pad, touch screen, microphone, or one or more push buttons, etc. The display devices may comprises, for example, cathode ray tubes (CRTs), liquid crystal display screens, gas plasma-based flat panel displays, indicator lights, or other types of display devices, etc. 
     The multi-function peripheral  103  also includes various components that are stored on the memory  116  and are executable by the processor  113 . These components include an operating system  136  and a multi-function control system  139 . The multi-function control system  139  includes an authentication system  143  according to an aspect of the present invention. 
     The operating system  136  is executed to control the allocation and usage of hardware resources in the multifunction peripheral such as the memory, processing time and peripheral devices. In this manner, the operating system  136  serves as the foundation on which applications depend as is generally known by those with ordinary skill in the art. 
     The multi-function control system  139  is executed by the processor  113  in order to control the various operations of the multi-function peripheral  103  in performing various functions including copying, scanning, printing, digital sending, and any other functions that may be formed by the multi-function peripheral  103 . The authentication system  143  is implemented in the multi-function peripheral  103  to authenticate a user to ensure that they are who they represent themselves to be and to limit access to the user to the various functions of the multi-function peripheral  103  to which that individual is entitled. In one embodiment, the authentication system  143  is programmed in an appropriate computer language, such as, for example, C, C++, Java, and other appropriate programming languages. 
     The memory  116  is defined herein as both volatile and nonvolatile memory and data storage components. Volatile components are those that do not retain data values upon loss of power. Nonvolatile components are those that retain data upon a loss of power. Thus, the memory  116  may comprise, for example, random access memory (RAM), read-only memory (ROM), hard disk drives, floppy disks accessed via an associated floppy disk drive, compact discs accessed via a compact disc drive, magnetic tapes accessed via an appropriate tape drive, and/or other memory components, or a combination of any two or more of these memory components. In addition, the RAM may comprise, for example, static random access memory (SRAM), dynamic random access memory (DRAM), or magnetic random access memory (MRAM) and other such devices. The ROM may comprise, for example, a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or other like memory device. 
     In addition, the processor  113  may represent multiple processors and the memory  116  may represent multiple memories that operate in parallel. In such a case, the local interface  119  may be an appropriate network that facilitates communication between any two of the multiple processors, between any processor and any one of the memories, or between any two of the memories etc. The processor  113  may be electrical or optical in nature. 
     Next, a discussion is provided of the general operation of the multi-function peripheral  103  in authenticating a user to provide access to the various functions of the multi-function peripheral  103 . Assume that a user approaches the multi-function peripheral  103  to perform one of the various functions provided thereby. For example, assume that a user wishes to scan in a document and transmit the same in a digital form to another individual using electronic mail. This may be done where the multifunction peripheral  103  is coupled to a network using a digital sending capability of the multifunction peripheral  103 . Further assume that the individual must be authenticated as there are a limited number of people who have access to the digital sending capability of the multifunction peripheral. 
     To begin, the user manipulates the user input device  126  to indicate the particular function that the user desires to employ on the multi-function peripheral  103 , such as the digital sending capability. In response, the multi-function control system  139  implements the authentication system  143  to verify that the user is the person that they claim to be in order to implement the appropriate function that they desire. The authentication system  143  thus displays a request on the display device  123  that the user enter appropriate user parameters such as, for example, a user password or user name, etc. Alternatively, the user may be required to provide user parameters such as biometric identification information or other identifying indicia through the various user input devices  126  employed with the multi-function peripheral  103 . 
     Such user input devices  126  may comprise, for example, a keyboard to enter a user name or password, as well as more complex user input devices  126 , such as a retinal scanner, fingerprint scanner, and/or other input devices. The user inputs the user parameters using one or more of the user input devices  126 . The authentication system  143  then verifies the user parameters. For example, the parameters to be entered may be a user&#39;s password and user name. Such information may be stored in a network server that is coupled to the multi-function peripheral  103  through a local area network or other network. The authentication system  143  may authenticate the user parameters by requesting that the network server verify that the user name and password are active on the network if such status provides access to the digital sending capabilities of the multifunction peripheral. Alternatively, such information may be maintained in a database that is consulted by the authentication system  143  to verify that the user has access to the digital sending capabilities. 
     With reference to  FIG. 2 , shown is a functional block diagram of the primary components of the authentication system  143  as it interacts with other components according to an embodiment of the present invention. As shown in  FIG. 2 , each block represents a module, object, or other grouping or encapsulation of underlying functionality as implemented in programming code. However, the same underlying functionality may exist in one or more modules, objects, or other groupings or encapsulations that differ from those shown in  FIG. 2  without departing from the present invention as defined by the appended claims. 
     The authentication system  143  includes an authentication manager  153  and a number of authentication agents  156 . According to an aspect of the present invention, the authentication system  143  can include any number of authentication agents  156 . Communication between the authentication manager  153  and the authentication agents  156  is accomplished by sending appropriate calls and responses to each other as is customary in an object-oriented environment. 
     The authentication system  143  also includes an agent priority table  159 . The agent priority table  159  is generated by the authentication manager  153  to track the existence of the authentication agents  156 . The authentication system  143  also interfaces with the user input devices  126  and with external authentication services  163  to obtain authentication of user parameters as will be described. In addition, the authentication system  143  interfaces with an application  166  that is implemented upon successful authentication of a user. In the case of the multi-function peripheral  103  ( FIG. 1 ), the application  166  may be a feature or function of the multi-function control system  139 . For example, the application  166  might be the digital sending function, copy function, or print function, etc. 
     Next, the operation of the authentication system  143  is described. To begin, upon startup of the multi-function peripheral  103 , the authentication manager  153  executes a method to discover all of the authentication agents  156  that are stored in the memory  116 . The discovery of the authentication agents  156  is accomplished, for example, using the Component Object Model (COM) created by Microsoft Corporation of Redmond, Wash. The COM architecture allows for the discovery of objects by employing a category manager with which objects are registered. For a discussion of the COM architecture, see Dale Rogerson,  Inside COM , Microsoft Press, Redmond, Wash., 1997, the entire text of which is incorporated herein by reference. 
     The discovered authentication agents  156  are then listed in the agent priority table  159  that is ultimately consulted by the authentication manager  153  in sending authentication requests to the respective authentication agents  156 . Each of the authentication agents  156  includes a priority level value. The order in which the authentication agents  156  are listed in the agent priority table  159  is based upon the priority level values within each of the authentication agents  156 . Alternatively, the order in which the authentication agents  156  are listed in the agent priority table  159  may depend upon the order in which each of the authentication agents  156  was registered or included in the authentication system  143 , or the order may be determined in some other manner. 
     The discovery of the authentication agents  156  in this manner points to the fact that the authentication system  143  is extensible in that there is no static coupling between the authentication manager  153  and the authentication agents  156 . That is to say, the authentication manager  153  does not know how many authentication agents  156  there are until discovered. The fact that such static coupling does not exist in the architecture of the authentication agent  143  allows for the easy addition of authentication agents  156  thereto in specific applications without having to modify the authentication manager  153 . Specifically, if a new type of authentication is desired for a particular function, all that is necessary is that a new authentication agent  156  be created and added to the authentication system  143 , thus reducing time and effort to accomplish such a modification. The extensibility of the authentication system  143  is further reflected in other interaction between the authentication manager  153  and the authentication agents  156  as will be discussed. 
     Each of the authentication agents  156  is configured to perform an authentication task that provides for the authentication of at least one user parameter that is supplied by a user by virtue of the user input devices  126 . Each authentication agent  156  may authenticate one or more user parameters supplied by the user. The user parameters that are authenticated by a respective agent  156  may include at least one parameter that may or may not be unique with respect to the remaining authentication agents  156 . 
     According to one aspect of the present invention, when a particular authentication agent  156  wishes to authenticate a parameter that was supplied by a user, then the authentication agent  156  may communicate with an appropriate external authentication service  163 . Such an external authorization service  163  serves to authenticate the specific parameter. For example, the external authentication service  163  may reside in a server coupled to a local area network or other network. Assume that the multi-function peripheral  103  is also coupled to the same network. Such an external authentication service  163  may be employed, for example, to verify that a specific username or password associated with a user that has access to a computer system on the network as can be appreciated by those with ordinary skill in the art. 
     Alternatively, the authentication agent  156  may include the functionality that causes the authentication of a particular parameter by itself without the use of an external authentication service  163 . The actual act of authentication may involve, for example, comparing an unauthenticated parameter with a table or database of known parameters for a match. When a match occurs, the parameter has been authenticated. Note there are many other approaches that may be employed to authenticate parameters as is generally known to those with ordinary skill in the art. 
     Assuming that a user wishes to employ the multi-function peripheral  103  ( FIG. 1 ) to perform a specific function such as transmitting a document by way of a digital sender, etc., then the user indicates the desired function through an appropriate user input device  126 . The authentication manager  153  then implements a “Request Authentication” method to obtain authentication of the user. Upon executing the Request Authentication method, the authentication manager  153  consults the agent priority table  159  to determine the first authentication agent  156  that is to be called upon to authenticate a particular parameter of the user. 
     The authentication manager  153  then sends a message to such authentication agent  156  that includes the desired function that the user wishes to implement on the multifunction peripheral  103 . Upon being called by the authentication manager  153  to authenticate the user, the first authentication agent  156  determines whether it is supposed to authenticate the user for the function that the user wishes to implement. That is to say, a particular authentication agent  156  may or may not be used to authenticate a user for a predetermined function of the multi-function peripheral  103 . 
     Assuming that the authentication agent  156  does perform an authentication procedure for the desired function, then the authentication agent  156  executes a method to query the user to enter or otherwise provide a user parameter for authentication. Assuming the user parameter is authenticated, the authentication agent  156  returns a “valid” message to the authentication manager  153  indicating that the user was authenticated. The authentication manager  153  then moves to obtain authentication from the next authentication agent  156 , if there are any remaining to query. If the authentication was unsuccessful, then the authentication agent  156  returns a “rejected” message indicating that the user has not been authenticated. In such case, the authentication manager  153  responds by denying the user access to the desired function of the multifunction peripheral  103  or other device. 
     If it is the case that the authentication agent  156  does not perform authentication for the desired function, then the authentication agent  156  returns a “valid” message to the authentication manager  153  indicating that the user has been authenticated. This action provides further evidence of the extensibility of the architecture of the authentication system  143 . In particular, if an authentication agent  156  is not to perform an authentication task for a specific desired function to be accessed, then by sending a “valid” reply, the authentication manager assumes that the user was authenticated by the specific authentication agent  156  an proceeds accordingly. Alternatively, a separate message may be sent to the authentication manager  153  by the authentication agent  156  that indicates that the authentication agent  156  does not perform authentication for the desired function. In such case, the authentication manager  153  should be configured to recognize such a message. In any event, the authentication manager  153  would proceed with the authentication procedure regardless of whether a “valid” message or an “inapplicable” message is received from the authentication agent  156 . 
     To authenticate a user, an authentication agent  156  first obtains the user parameter through an appropriate user input device  126 . Thereafter, the authentication agent  156  either performs the authentication of the user parameter itself or requests an external authentication service  163  to authenticate the user parameter. 
     In implementing the Request Authentication method, the authentication manager  153  sends an authentication request to each one of the authentication agents  156  based upon the position in the agent priority table  159 . Upon receiving a response that indicates that the authentication was a success from any one of the authentication agents  156 , then the authentication manager  153  proceeds to request authentication from the next authentication agent  156  listed in the agent priority table  159  until the last authentication agent  156  is queried. When the last authentication agent  156  has indicated that the user has been authenticated whether the authentication agent  156  performs an authentication task or is bypassed, then the authentication manager  153  returns the final authentication result (i.e. passed or failed) to the multifunction control system  139 . The multifunction control system  139  then either allows or prevents the desired function in the multifunction peripheral  153  that the user wishes to access. 
     Turning to  FIGS. 3 and 4 , shown are block diagrams of the authentication manager  153  and the authentication agent  156  according to an aspect of the present invention. In this respect, the authentication manager  153  includes a “discover” method  173  and a “request authentication” method  176 . The authentication agent includes an “authenticate” method  179  that is implemented to authenticate the user. Also associated with the authentication agent  156  are function variables  183  and a priority level variable  186 . The function variables  183  identify those functions of the multi-function peripheral  103  or other device for which the authentication agent  156  implements the Authenticate method  179 . The priority level variable  186  provides a benchmark by which the authentication agent  156  is to be listed in the agent priority table  159  ( FIG. 2 ). 
     With reference to  FIG. 5 , shown is a flowchart of the Request Authentication method  176  according to an aspect of the present invention. Alternatively, the flowchart of  FIG. 5  may be viewed as depicting steps in a method implemented in the multi-function peripheral  103  in authenticating a user. 
     Beginning with box  206 , the first authentication agent  156  ( FIG. 2 ) to which an authentication request is to be sent is looked up in the agent priority table  159  ( FIG. 2 ). Thereafter, in box  209  the Request Authentication method  176  sends an authentication request to the authentication agent  156  identified in box  206 . Then, in box  213  the Request Authentication method  176  determines whether it has received a response from the authentication agent  156  ( FIG. 2 ). If not, then the request authentication  176  proceeds to box  216  in which it is determines whether a time-out period has tolled. 
     The time-out is a predefined value that is stored in the memory  116 . The authentication system  143  includes a timer that tracks whether or not the time that the authentication manager  153  waits for a response from the respective authentication agent  156  has gone beyond the predefined time-out. If there is no time-out in block  216 , then the Request Authentication method  176  reverts back to box  213 . 
     If a response is received from the authentication agent  156  in box  213 , then the Request Authentication method  176  proceeds to box  219 . In box  219 , the Request Authentication method  176  determines whether the response from the authentication agent  156  indicates whether the user has been authenticated or whether the user was not successfully authenticated. Specifically, such response may indicate that the user is “valid” or “rejected”, etc. If the authentication was unsuccessful, then the Request Authentication method  176  proceeds to box  223 . The Request Authentication method  176  also proceeds to box  223  upon an occurrence of a time-out in box  216 . In box  223  an indication of an authentication failure is provided to the user through an appropriate display device  123  ( FIG. 1 ) and the user is denied access to the desired function of the multifunction peripheral  103 . Thereafter, the Request Authentication method  176  ends as shown. 
     With reference back to box  219 , if the response from the authentication agent  156  indicates that the authentication of the user was successful, then the Request Authentication method  176  proceeds to box  226  in which it is determined whether authentication agents  156  remain in the agent priority table  159  to which an authentication request has not been sent. If so, then the Request Authentication method  176  moves to box  229  in which the next authentication agent  156  is looked up in the agent priority table  159 . Thereafter, the Request Authentication method  176  reverts back to box  209  to interface with the next authentication agent  156  to perform the next authentication task. With reference back to box  226 , if the last authentication agent  156  has performed its authentication task as requested by the Request Authentication method  176 , then the Request Authentication method  176  proceeds to box  233  in which an appropriate application  166  is implemented that enables the desired function within the multi-function peripheral  103  for use by the user. It is understood that the authentication system  143  ( FIG. 2 ) may be employed with any appropriate system or device and that the multifunction peripheral  103  is discussed herein merely to provide an example of the use of the authentication system  143 . 
     With reference to  FIG. 6 , shown is a flowchart of the Authenticate method  179  according to another aspect of the present invention. Alternatively, the flowchart of  FIG. 6  may be viewed as depicting steps in a method implemented in the multi-function peripheral  103  according to the present invention. The Authenticate method  179  is implemented within the authentication agent  156  ( FIG. 2 ) in order to perform or broker the performance of an authentication task as requested by the authentication manager  153  ( FIG. 2 ). 
     Beginning with box  250 , the Authenticate method  179  first receives the authentication request from the authentication manager  153 . The authentication request identifies the function that a user wishes to employ in the multi-function peripheral  103  for which the user is to be authenticated. The function may be identified, for example, as an attribute in the request. In box  250  the Authenticate method  179  compares the function in the request with the function variables  183  ( FIG. 4 ) associated with itself. Then, in box  253 , if a match between the supplied function and one of the function variables  183  is not detected, then the Authenticate method  179  proceeds to box  256  in which a message is sent back to the authentication manager  153  that indicates that the authentication was successful. This is done even though there was no authentication performed since the authentication agent  156  does not perform authentication services for the particular function in question as was described above. Alternatively, a response may be sent to the authentication manager  153  that the authentication agent  156  is not applicable to the specified function. In such case, the authentication manager  153  assumes that the authentication was successful and proceeds to request authentication from the remaining authentication agents  156  as described previously. 
     With reference back to box  253 , if there is a match detected between the function in the request and the function variables  183  associated with the authentication agent  156 , then the Authenticate method  179  proceeds to box  259  in which user parameters are obtained from the user through an appropriate user input device  126 . In this respect, the authentication agent  156  may implement appropriate methods or logic that generate various input interfaces as can be appreciated by those with ordinary skill in the art. 
     Once the user inputs the user parameters, then the Authenticate method  179  proceeds to box  263  to obtain authentication of the user parameters from an external authentication service  163  ( FIG. 2 ). Alternatively, in box  263 , the Authenticate method  179  may perform the authentication function itself. The authentication may entail, for example, comparing the user parameter received from the user with a known list or database of user parameters to determine whether a user is listed as having privileges to perform various functions on the multi-function peripheral  103  or other device. 
     The various user parameter that may be input into the authentication system  143  for verification by the various authentication agents  156  may include, for example, a user password, pin number, a user name, biometric information such as, fingerprints, retinal scans, voice scans, DNA information, smart card parameters, ID card parameters, and other quantifiable information. 
     In box  266 , the Authenticate method  179  determines whether the user parameters have been authenticated by the external authentication services  163 . If in box  266  the authentication has failed, then in box  269  the Authenticate method  179  returns a message to the authentication manager  153  informing the manager that the authentication was unsuccessful. Such a response may include an “invalid” indicator or other indication. Thereafter, the Authenticate method  179  ends accordingly. 
     On the other hand, if the authentication was successful in box  263 , then the Authenticate method  179  proceeds to box  256  in which a message is returned to the authentication manager  153  indicating that the authentication of the user parameter was successful. Thereafter, the Authenticate method ends accordingly. 
     With reference back to  FIG. 2 , the architecture of the authenticate system  143  provides several advantages. One of these advantages includes the fact that additional authentication tasks may be added to the authentication system by simply adding an appropriate authentication agent  156  without making any change to the authentication manager  153  or existing authentication agents  156 , etc. Also, to create a new authentication agent  156 , an existing authentication agent  156  may be copied and modified rather than creating the new authentication agent  156  from scratch. Other advantages of the present invention will be apparent to one with ordinary skill in the art. 
     With reference back to  FIG. 2 , although the authentication system  143  of the present invention is embodied in software or code executed by general purpose hardware as discussed above, as an alternative the authentication system  143  may also be embodied in dedicated hardware or a combination of software/general purpose hardware and dedicated hardware. If embodied in dedicated hardware, the authentication system  143  can be implemented as a circuit or state machine that employs any one of or a combination of a number of technologies. These technologies may include, but are not limited to, discrete logic circuits having logic gates for implementing various logic functions upon an application of one or more data signals, application specific integrated circuits having appropriate logic gates, programmable gate arrays (PGA), field programmable gate arrays (FPGA), or other components, etc. Such technologies are generally well known by those skilled in the art and, consequently, are not described in detail herein. 
     The block diagrams and/or flow charts of  FIGS. 2–6  show the architecture, functionality, and operation of an implementation of the authentication system  143 . If embodied in software, each block may represent a module, segment, or portion of code that comprises program instructions to implement the specified logical function(s). The program instructions may be embodied in the form of source code that comprises human-readable statements written in a programming language or machine code that comprises numerical instructions recognizable by a suitable execution system such as a processor in a computer system or other system. The machine code may be converted from the source code, etc. If embodied in hardware, each block may represent a circuit or a number of interconnected circuits to implement the specified logical function(s). 
     Although the block diagrams and/or flow charts of  FIGS. 2–6  show a specific order of execution, it is understood that the order of execution may differ from that which is depicted. For example, the order of execution of two or more blocks may be scrambled relative to the order shown. Also, two or more blocks shown in succession in  FIGS. 5 and 6  may be executed concurrently or with partial concurrence. In addition, any number of counters, state variables, warning semaphores, or messages might be added to the logical flow described herein, for purposes of enhanced utility, accounting, performance measurement, or providing troubleshooting aids, etc. It is understood that all such variations are within the scope of the present invention. Also, the block diagrams and/or flow charts of  FIGS. 2–6  show are relatively self-explanatory and are understood by those with ordinary skill in the art to the extent that software and/or hardware can be created by one with ordinary skill in the art to carry out the various logical functions as described herein. 
     Also, where the authentication system  143  comprises software or code, it can be embodied in any computer-readable medium for use by or in connection with an instruction execution system such as, for example, a processor in a computer system or other system. In this sense, the logic may comprise, for example, statements including instructions and declarations that can be fetched from the computer-readable medium and executed by the instruction execution system. In the context of the present invention, a “computer-readable medium” can be any medium that can contain, store, or maintain the authentication system  143  for use by or in connection with the instruction execution system. The computer readable medium can comprise any one of many physical media such as, for example, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor media. More specific examples of a suitable computer-readable medium would include, but are not limited to, magnetic tapes, magnetic floppy diskettes, magnetic hard drives, or compact discs. Also, the computer-readable medium may be a random access memory (RAM) including, for example, static random access memory (SRAM) and dynamic random access memory (DRAM), or magnetic random access memory (MRAM). In addition, the computer-readable medium may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or other type of memory device. 
     Although the invention is shown and described with respect to certain preferred embodiments, it is obvious that equivalents and modifications will occur to others skilled in the art upon the reading and understanding of the specification. The present invention includes all such equivalents and modifications, and is limited only by the scope of the claims.