Abstract:
A system and method whereby the identity of a person, entity, device or the like attempting to gain access to a secured resource may be securely authenticated includes a means for receiving from a requester purporting to be an authorized user of a secured resource a request for access to the secured resource; means for generating and communicating to the purported authorized user a challenge string adapted to provide a basis for authenticating the identity of the requester; a means for receiving a response string corresponding to the challenge string; and a means for evaluating the response string to authenticate the identity of the requester.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to security protocols for use in securing and/or restricting access to personal other confidential information, physical locations and the like. More particularly, the invention relates to a system whereby the identity of a person, entity, device or the like attempting to gain access to a secured resource may be securely authenticated. 
       BACKGROUND OF THE INVENTION 
       [0002]    The protection of personal information and/or other secured resources, such as, for example, credit data, medical history, financial account information, secured physical locations and the like is of ever increasing concern to businesses and individuals alike. To be sure, each passing day reveals more sophisticated attacks by those who would gain unauthorized access to such resources absent the constant vigilance of those charged with the protection of such resources. To this end, the various security protocols employed for the protection of such resources almost universally includes some means for authenticating the identity of a person, entity, device or the like attempting to gain access to a secured resource. 
         [0003]    More often than not the critical authentication is carried out by the age old process of a providing a privately held password, personal identification number or the like in connection with some generally publicly known identifier for the person, entity, device or the like attempting to gain access to the secured resource. Unfortunately, however, this protocol is dogged by vulnerability to interception through spoofing, eavesdropping, and countless other techniques though which a password, personal identification number or the like may become known to an attacker. Additionally, it is common to find that a single person, entity, device or the like uses the same password, personal identification number or the like in connection with gaining access to multiple secured resources. In such case, a security breach in connection with a single secured resource may jeopardize the security of all other secured resources. 
         [0004]    Giving the fundamentally flawed state of the art with respect to password type protection, it is therefore the overriding object of the present invention to improve over the prior art by providing a system by which authentication may be more securely conducted. Additionally, it is an object of the present invention to provide such a system that is robust in specific implementation and readily usable by any manner of person, entity, device or the like. Finally, it is an object of the present invention to provide such a system that is economical in implementation and therefore readily accessible to virtually any application. 
       SUMMARY OF THE INVENTION 
       [0005]    In accordance with the foregoing objects, the present invention—an authentication system for authenticating the identity of a requester of access to a secured resource—generally comprises a means for receiving from a requester purporting to be an authorized user of a secured resource a request for access to the secured resource; means for generating and communicating to the purported authorized user a challenge string adapted to provide a basis for authenticating the identity of the requester; a means for receiving a response string corresponding to the challenge string; and a means for evaluating the response string to authenticate the identity of the requester. 
         [0006]    In at least some implementations of the present invention, the authentication system further comprises a means for evaluating the response string to determine whether as a result of passage of time the response string should be deemed to be invalid regardless of content. 
         [0007]    In at least some implementations of the present invention, the authentication system further comprises a means for establishing a test adapted to detect the existence of a spoofing type deception and in at least some embodiments of these implementations the test may also be adapted to at least in part authenticate the identity of the requester. 
         [0008]    Finally, many other features, objects and advantages of the present invention will be apparent to those of ordinary skill in the relevant arts, especially in light of the foregoing discussions and the following drawings, exemplary detailed description and appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    Although the scope of the present invention is much broader than any particular embodiment, a detailed description of the preferred embodiment follows together with illustrative figures, wherein like reference numerals refer to like components, and wherein: 
           [0010]      FIG. 1  shows, in an overview use case diagram, the various basic functionality implemented in the preferred embodiment of the authentication system and method of the present invention; 
           [0011]      FIG. 2  shows, in a flowchart, an overview of the various steps generally taken in making a request for access to a secured resource in accordance with the present invention; 
           [0012]      FIG. 3  shows, in a flowchart, an overview of the various steps generally taken in validating the purported access right of a user requesting access to a secured resource in accordance with the present invention; 
           [0013]      FIG. 4  shows, in an overview sequence diagram, various interactions as generally take place during the operation of the authentication system and method of the present invention; 
           [0014]      FIG. 5  shows, in a deployment diagram, an exemplary hardware and software implementation of the authentication system and method of the present invention; 
           [0015]      FIG. 6  shows, in a deployment diagram, various details of a representative web interface implementation of a user interface for use in connection with the exemplary hardware and software implementation of  FIG. 5 ; 
           [0016]      FIG. 7  shows, in an elevational representation, various details of a representative terminal device interface implementation of a user interface for use in connection with the exemplary hardware and software implementation of  FIG. 5  such as may, in particular, be provided in connection with a service client implementing functionality of the present invention; 
           [0017]      FIG. 8  shows, in a class diagram, a high level schema for a representative user database as may be implemented in connection with the exemplary hardware and software implementation of  FIG. 5 ; 
           [0018]      FIG. 9  shows, in a class diagram, a high level schema for a representative transaction database as may be implemented in connection with the exemplary hardware and software implementation of  FIG. 5 ; 
           [0019]      FIG. 10  shows, in a screen representation of a web browsing application, a first exemplary implementation of an order completion page from a website showing, in particular, various details of the manner for making in accordance with the present invention a request for access to a secured resource; 
           [0020]      FIG. 11  shows, in a top plan representation of a mobile telecommunications device screen, a first example of a challenge message such as may be implemented in accordance with the present invention; 
           [0021]      FIG. 12  shows, in a top plan representation of a mobile telecommunications device screen, a second example of a challenge message such as may be implemented in accordance with the present invention showing, in particular, extended functionality for use in detecting a spoofing type deception; 
           [0022]      FIG. 13  shows, in a top plan representation of a mobile telecommunications device screen, a third example of a challenge message such as may be implemented in accordance with the present invention showing, in particular, extended functionality for accommodating constraints imposed by the available means for submitting of an authentication credential for purposes of validating the purported access right of a user requesting access to a secured resource in accordance with the present invention; 
           [0023]      FIG. 14  shows, in a screen representation of a web browsing application, a first exemplary implementation of a payment confirmation page from a website showing, in particular, various details of the manner for submitting of an authentication credential for purposes of validating the purported access right of a user requesting access to a secured resource in accordance with the present invention; 
           [0024]      FIG. 15  shows, in a screen representation of a web browsing application, a second exemplary implementation of a payment confirmation page from a website showing, in particular, various details of the manner for submitting of an authentication credential for purposes of validating the purported access right of a user requesting access to a secured resource in accordance with the present invention; 
           [0025]      FIG. 16  shows, in a screen representation of a web browsing application, an exemplary implementation of a preliminary payment confirmation page from a website showing, in particular, various details of at least one method for accessing a further payment confirmation page; 
           [0026]      FIG. 17  shows, in a screen representation of a web browsing application, a third exemplary implementation of a payment confirmation page from a website showing, in particular, various details of a first implementation of extended functionality for use in detecting a spoofing type deception; 
           [0027]      FIG. 18  shows, in a screen representation of a web browsing application, the implementation of the payment confirmation page of  FIG. 17  showing, in particular, various additional details of the implemented extended functionality for use in detecting a spoofing type deception; and 
           [0028]      FIG. 19  shows, in a screen representation of a web browsing application, a fourth exemplary implementation of a payment confirmation page from a website showing, in particular, various details of second implementation of extended functionality for use in detecting a spoofing type deception. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0029]    Although those of ordinary skill in the art will readily recognize many alternative embodiments, especially in light of the illustrations provided herein, this detailed description is exemplary of the preferred embodiment of the present invention, the scope of which is limited only by the claims appended hereto. 
         [0030]    Referring now to the figures, and to  FIG. 1  in particular, the authentication system  30  of the present invention is shown to generally comprise an operative combination of a plurality of service provider implemented use cases  32 . In particular, the service provider  36  of the present invention will generally provide for an end user actor  34  a means  38  for requesting access to a secured resource and, additionally, a means  37  for submitting an authentication credential for use in validating the purported access right of the end user actor  34 . 
         [0031]    Additionally, as also particularly shown in  FIG. 1 , the service provider  36  of the present invention will generally provide responsive to submission by an end user actor  34  of a request for access to a secured resource a means  39  for generating and sending to an end user actor  34  a challenge message  94  designed to enable only the intended end user actor  34  to determine the content of a transient authentication credential. Still further, the service provider  36  of the present invention will generally provide responsive to submission by an end user actor  34  of an authentication credential a means  41  for validating the authentication credential. 
         [0032]    In an extension of the present invention particularly useful in implementations comprising an Internet website-based or other user interface  105  generally susceptible to spoofing type deceptions, the service provider  36  may in combination with the means  37  for submitting an authentication credential also be adapted to provide for the end user actor  34  a means  35  for detecting the existence of a spoofing type deception. In implementation of such an extension of the present invention, the service provider  36  may in combination with the means  39  for generating and sending to an end user actor  34  a challenge message  94  also be adapted to provide a means  82  for generating content for use in the means for detecting the existence of a spoofing type deception and to provide such content to the end user actor  34 . 
         [0033]    Finally, it is noted that time  44  as an actor may be accommodated as desired in any particular implementation wherein the service provider  36  is also provided with means  45  responsive to the passage of time for revoking or otherwise invalidating an authentication credential such that an authentication credential otherwise correctly determined by an end user actor  34  in response to a service provider generated challenge message  94  may as a result of the passage of time be deemed to be incorrect, thereby resulting in a validation failure upon application of the means  45  for validating the authentication credential. 
         [0034]    Referring now then to  FIGS. 2 through 4  in particular, the authentication method  46  of the present invention as operative upon the described authentication system  30  is shown to generally comprise various series of interactions, as broadly set out in  FIG. 4 , wherein the interactions may be generally categorized as steps  47  implicated in requesting access to a secured resource, as broadly set out in  FIG. 2 , and steps  48  implicated in validating the purported access right of the user requesting access to the secured resource, as broadly set out in  FIG. 3 . 
         [0035]    As particularly shown in  FIGS. 2 and 4 , the authentication method  46  of the present invention generally begins with an end user  34  submitting or otherwise making through an access controller  51 , firewall or like access control point a request for access to a secured resource, which end user submitted request is then forwarded by the access controller  51  to an authenticator  52 . Although generally considered to be an optional feature of the present invention, it is noted that prior to forwarding the end user submitted request to the authenticator  52  the access controller  51  may, if desired, first determine whether the end user  34  making the request is authorized or otherwise permitted to make such use of the authentication system  30 . If in an implementation of this feature it is determined that the end user  34  is not authorized or otherwise permitted to make the attempted use of the authentication system  30  the instigated process  47  will generally terminate whereas if it is determined that the end user  34  is authorized or otherwise permitted to make the attempted use of the authentication system  30  the process  47  will generally continue. 
         [0036]    In any case, once an end user submitted request is forwarded by the access controller  51  to the authenticator  52  the remaining processing of the request is conducted by the authenticator  52 . In particular, it is noted that in an important aspect of the present invention the authenticator  52  must be able to evaluate the end user submitted request to determine the specific identity of the resource for which the request is made. To this end, as will be better understood further herein, the forwarded request preferably comprises at least the common identifier for the resource. In any case, if the available information is insufficient for the authenticator  52  to positively determine the identity of the resource for which the end user  34  has requested access the process  47  will generally terminate whereas if the available information is sufficient for the authenticator  52  to positively determine the identity of the resource for which the end user  34  has requested access the process  47  will generally continue. 
         [0037]    In the final steps for processing  47  an end user submitted request for access to a secured resource, the authenticator  52  generates a challenge message  94  designed to enable only an authorized end user  34  to determine the content of a transient authentication credential and, thereafter, issues the challenge message  94  to the end user  34 . In connection with the step of generating the challenge message  94 , however, and as a predicate to the step of issuing the challenge message  94 , an authenticator  52  implemented as part of an authentication system  30  that also comprises a means  35  for detecting the existence of a spoofing type deception must be adapted to determine whether under the circumstances of the particular in process request for access to a secured resource such a means  35  for detecting the existence of a spoofing type deception should be deployed. If in such an implementation it is determined that no test for detecting the existence of a spoofing type deception need be established the challenge message  94  is issued without more whereas if it is determined that a test for detecting the existence of a spoofing type deception should be deployed the authenticator  52  will establish the parameters of an appropriate test and include the established parameters in connection with or as part of the issued challenge. 
         [0038]    With the challenge message  94  issued by the service provider  36  to the end user  34 , the end user  34  then formulates a response to the challenge based upon information generally known only to the end user  34  and the authenticator  52 . Once the end user  34  has formulated a response to the challenge, and assuming that the end user  34  desires to continue the in-process transaction, the end user  34  will submit the formulated response to the access controller  51  as an authentication credential. 
         [0039]    Referring now then to  FIGS. 3 and 4  in particular, validation  48  of the purported access right of the user requesting access to a secured resource is shown to generally begin with the submission by the end user  34  through the access controller  51  of an authentication credential to be forwarded by the access controller  51  to the authenticator  52 , which authentication credential has been previously formulated by the end user  34  in response to issuance by the authenticator  52  of a challenge message  94 . As shown in  FIG. 3 , however, in an implementation of an authentication system  30  that comprises a means  35  for detecting the existence of a spoofing type deception, the access controller  51  will prior to allowing submission by the end user  34  of an authentication credential first determine whether under the circumstances of the particular request in process for access to a secured resource such a means  35  for detecting the existence of a spoofing type deception should be deployed. If in such an implementation it is determined by the access controller  51  that no test for detecting the existence of a spoofing type deception need be established the end user  34  is allowed by the access controller  51  to submit the authentication credential without more whereas if it is determined by the access controller  51  that a test for detecting the existence of a spoofing type deception should be deployed the access controller  51  will present to the end user  34  an appropriate test for detecting the existence of a spoofing type deception, wherein the presented test is constructed by the access controller  51  using the test parameters as previously established and provided by the authenticator  52 . 
         [0040]    In any case, upon successful forwarding by the access controller  51  to the authenticator  52  of the end user submitted authentication credential, the authenticator  52  proceeds to validate the responsive authentication credential by comparing the authentication credential against a key string. As will be appreciated by those of ordinary skill in the art in light of this exemplary description, the key string will prior to or at the time of validation be determined by the authenticator  52  utilizing knowledge of the previously discussed information generally known only to the end user  34  and the authenticator  52  to formulate the key string as the known correct response to at least a portion of the previously issued challenge message  94  (the “primary challenge”). In addition to comparison of the authentication credential to a known key string, however, it is noted that in an authentication system  30  utilizing time  44  as an actor in order to provide a timeout for the validity of an outstanding challenge message  94 , the authenticator  52  will be programmed or otherwise adapted to determine as part of the validation step whether as a result of the passage of time the authentication credential should be deemed to be incorrect. In any case, if the authentication credential is found or otherwise deemed to be incorrect, the authenticator  52  will report the incorrect finding to the access controller  51  and the end user  34  will be blocked by the access controller  51  from access to the requested secured resource. If, on the other hand, the authentication credential is found to be correct the authenticator  52  will report the correct finding to the access controller  51  and the access controller  51  will provide the requested access to the end user  34 . 
         [0041]    With the foregoing broad overview of the general structure and function of the authentication system  30  of the present invention in mind, it is now noted that in accordance with the present invention an end user  34  may comprise any person or machine requiring, in connection with some other use, access or other relationship with a service provider  36 , access to a secured resource for which the service provider  36  controls access. By way of simple example, the resource may comprise password protected information (a secured resource) maintained in a computer system under the control of the service provider  36  and to which a human end user  34  desires access. In a critical aspect of all implementations of the present invention, however, the actual password or other information known by the end user  34  and the service provider  36  and through which the authenticator  52  is capable of authenticating the access right of the end user  34  is strictly prohibited from submission through the user interface  105  in connection with the making of a request or submission of an authentication credential. 
         [0042]    With this in mind, the end user  34  may, for example and without limitation, be a patient wishing to access medical information (a secured resource) held by a caregiver or an insurance carrier (a service provider  36 ); or may be the holder of a credit card account, banking account, automated teller machine (“ATM”) card and/or card or the like (a secured resource) wishing to authorize a credit card processor, financial institution or the like to complete a transaction; or may be a credit applicant or other holder of an information product wishing to access a credit score or other information (a secured resource) maintained by a credit bureau or other information provider (a service provider  36 ); or may be the holder of an on-line service account protected by a password (a secured resource) and wherein the on-line account is under the control of the service provider  36 . 
         [0043]    In any case, in order to better describe the critical and other aspects of the present invention reference is now made to the deployment diagram of  FIG. 5 , wherein there is shown the various elements of an exemplary hardware and software based implementation of an authentication system  30  constructed in accordance with the teachings of the present invention. Before continuing, however, it is noted that while the implementation depicted in  FIG. 5  is exemplary of the authentication system  30  of the present invention, it is in no manner meant to be all encompassing or otherwise limiting of the wide range of implementations as are possible. In addition, it is noted that while some elements are in  FIG. 5  shown to comprise hardware and others software, virtually any element could be implemented in either hardware or software or any combination thereof. Still further, it is noted that while for clarity of discussion various hardware elements are segregated between different machines and various software elements are segregated into various components, no such segregation should be deemed as required unless specifically stated herein and further or differing division into various particular components, modules, classes, objects or the like should be taken as within the scope of the present invention as limited only by the claims appended hereto. Finally, to the extent that any structural (including software) element is stated as being adapted to perform some function, such language is to be taken as a positive structural limitation imposed upon the referenced element whereby the element is required to be actually adapted, programmed, configured or otherwise provided with the actual capability for performing the specified function. In no case shall such language be taken as merely a statement of intended use or the like, but to the contrary such language shall be in every case taken to read on all structures of the referenced element that are in any manner actually in the present tense configured to perform the specified function (as opposed to being merely capable of adaption for the conduct of the specified function). 
         [0044]    Turning then to  FIG. 5 , a service provider  36  (such as, for example, may comprise a specialized provider of the authentication services of the present invention; a provider of other products or services having need of authentication services, such as, for example, a credit card processor or financial institution or an alarm monitoring company; a retail store, service station, on-line service provider or merchandiser or other business; a healthcare or medical insurance provider; an automated teller machine provider; or the like) has associated therewith one or more application servers  50  or database servers  98  upon which may be hosted software functionality necessary to operation within the framework of the present invention in addition to the unrelated operations of the service provider  36 . In particular, an application server  50  may host an access controller  51 , firewall or other access control point to process and/or otherwise handle requests and submissions from an end user  34  as well as to produce output for the end user  34  as may be necessary in the operation of the present invention. Additionally, the application server  50  may host an authenticator  52  adapted to handle or otherwise control all aspects of the authentication process within the realm of responsibility of the authentication system  30 , including receiving authentication requests, storing and/or retrieving data pertinent to the processing of such requests, directing the generation and sending of challenge messages  94 , and directing the validation of authentication credentials submitted in response to challenge messages  94  and actions taken based upon the results of such validations. In order to improve efficiency, the authenticator component  52  may comprise one or more further specialized components such as, for example, a challenge manager  53  adapted to facilitate creation and transmission of challenge messages  94 , a random sequence generator  54  as may be useful in the highly specialized task of creating random sequences which, as will be better understood further herein, are an integral feature of the present invention, and a validation tool  55  adapted to conduct the specialized task of comparing received authentication credentials with known key strings. Additionally, the application server  50  may also host an administration tool  56  through which various aspects of the setup, maintenance and operation of the hardware and software systems of the authentication system  30  may be managed. 
         [0045]    In order to efficiently manage and handle the large quantity of data that may typically be stored in connection with an implementation of the present invention, one or more dedicated database servers  98  hosting database management systems  57  are generally desired. As shown in  FIG. 5 , a typical database management system  57  may include a user database  58  for storing a wide variety of generally user centric data as may be required in the operation of the present invention, a transaction database  59  for storing data generally associated with the conduct of individual transactions and an image database  107 , which, as will be better understood further herein, is particularly adapted for storing data associated with implementation of the means  35  for detecting the existence of a spoofing type deception. Although those of ordinary skill in the art will recognize that virtually unlimited alternatives are possible,  FIG. 8  shows a very high level but generally representative schema for a user database  58  and  FIG. 9  shows a very high level but also generally representative schema for a transaction database  59 , each of which will be described in greater detail further herein in connection with an exemplary description of the conduct of a typical transaction. 
         [0046]    Additionally, a preferably unified messaging gateway  60  is provided for use in issuing challenge messages  94  through various communication channels to end users  34 . As will be appreciated by those of ordinary skill in the art, such a unified messaging gateway  60  may be utilized to transmit a generated challenge message  94  in any of a plurality of message formats (such as, for example, as a short messaging service (“SMS”) message, a standard text message, an electronic mail message, a synthesized voice message, an alphanumeric page or the like) over any of a plurality of communication channels (such as, for example, an SMS or other text channel, a simple mail transport protocol (“SMTP”) channel, a plain old telephone system (“POTS”) channel, a paging network or private broadcast channel or the like) to be received by any of a plurality of user devices (such as, for example, a mobile or landline telephone, a smart phone, an electronic mail client, a personal data assistant (“PDA”), a numeric or digital pager or the like). Still further, a user interface  105  is provided and adapted to provide input from all manner of users  62 , including administrative users and end users  34 , to the hardware and/or software systems of the service provider  36  and to provide output from these systems to the various users  62 . As will be appreciated by those of ordinary skill in the art, the user interface  105  enables the various users  62  to maintain and/or otherwise manage the data stored in the user database  58  as may be appropriate as well as to generally manage and maintain the implemented authentication system  30  in addition to providing, in accordance with the present invention, a point of access for the end user  34 . 
         [0047]    As exemplified by  FIGS. 6 and 7 , the user interface  105  may take a wide variety of forms depending upon the circumstances of any particular implementation. For example, as shown in  FIG. 6 , a typical user interface may be implemented as a web interface  63  wherein there may be provided a page processor  64  hosted on an appropriate execution environment  65  installed on a dedicated web server  66  in Internet communication  67  with a user device  68 , such as, for example, a personal computer, a smart phone, other mobile device  78  or the like, and on which is installed and/or hosted a web browser running  69  in a provided execution environment  70 . On the other hand, as shown in  FIG. 7 , a user interface  105  may comprise a more dedicated and integrated arrangement such as the depicted point-of-sale (“POS”), fueling station or automated teller machine (“ATM”) terminal device  73  comprising as input modalities a keypad  95  and a card reader and comprising as an output modality a visual display such as the depicted screen  77 . Additionally, those of ordinary skill in the art will recognize that in addition to the depicted implementations, the user interface  105  may comprise a network interface such as may be utilized by a customer service representative (considered herein as an end user  34  acting through the representative), a telephone auto attendant, which may implement a DTMF decoder, speech recognition engine, TDD/TTY decoder or the like; or virtually any other combination of input modalities (including barcode readers or scanners, keyboards, keypads, card and/or magnetic stripe readers, pointing devices, microphones and the like) and output modalities (including visual displays such as computer or other device monitors or screens, audio output devices such as headphones or other speakers, tactile output devices such as may be adapted for the visually impaired and the like). 
         [0048]    Continuing then with the example generally described with respect to  FIG. 5 , further details of the implementation are now described by way of the following detailed description of a possible use of the implementation for conducting a retail purchase transaction, which, for purposes of this present example, shall be taken as completion of a purchase at an on-line retailer (the service provider  36 ) by a consumer (the end user  34 ) having available for payment a merchant or store credit card (secured resource) for which a Card Verification (“CV”) or like code must be provided as a condition precedent to authorization of a credit card charge. To complete the transaction, the consumer will indicate a desire to make a credit card payment to the on-line retailer by using a web browser  69  to submit a request through an access controller  51  which will then forward the consumer&#39;s request (which will generally include the credit card number) to the authenticator  52  for determination of whether the identified credit card is a valid secured resource connected with the authentication system  30 , for authentication of the consumer&#39;s right of access to the identified credit card and for completing the payment transaction. In accordance with a critical aspect of the present invention, however, the CV or like code required under the present example for authorization of the transaction must not be provided through the user interface  105  (in this case, a web interface  63 ). 
         [0049]    To begin the process, then, the consumer (end user  34 ) will use his or her web browser  69  to first navigate to the uniform resource locator (“URL”) of an order completion webpage  75  for the on-line retailer (service provider  36 ). As is otherwise conventional, the consumer&#39;s web browser  69  will send a page request to the on-line retailer&#39;s web server  66  where a hosted page processor  64  will create and send back to the consumer&#39;s web browser  69  the requested “order completion” webpage  75 , making use, if required, of the on-line retailer&#39;s database management system  57  to retrieve stored information pertaining to the consumer, the transaction or the like. As shown in  FIG. 10 , the requested page  75  may simply comprise a simple form through which the consumer may input information indicative of the nature of the consumer&#39;s request for access to a secured resource. In this case, the consumer enters the credit card number (the common identifier for the secured resource) for the merchant or store credit card for which he or she requests use (access) and then selects the depicted “pay now” button. With the data entered as shown, the consumer&#39;s web browser  69  submits the data to the on-line retailer&#39;s web server  66  where the hosted page processor  64  may validate the form data for technical completeness and accurate formatting. Assuming that the submitted data is technically correct or is subsequently made technically correct, the page processor  64  submits the consumer&#39;s request to the access controller  51  hosted on the on-line retailer&#39;s application server  50 . 
         [0050]    At this point, in an optional feature of the present invention, the on-line retailer may choose to verify that the tentatively identified consumer presenting the credit card is permitted to make use of the on-line retailer&#39;s services for the requested purposes. For example, it may be that the on-line retailer requires registration prior to use of the authentication system  30  and method  46  of the present invention which, it is noted, may be utilized in a completely anonymous fashion to conduct extraordinarily secure financial and other transactions. If so, the access controller  51  may access the user table  85  of the user database  58  or any other accessible data store to determine that the tentatively identified consumer is a valid end user  34 . 
         [0051]    In any case, the access controller  51  will generally continue by creating a transaction reference for the transaction and assembling any other necessary parameters, such as payment amount. As will be appreciated by those of ordinary skill in the art, under many circumstances a service provider  36  will have available all or virtually all information necessary for submitting (on behalf of an end user  34 ) a request for access to a secured resource without need for the end user  34  to enter additional data. For example, in a case where the consumer is otherwise “logged in” to the on-line retailer&#39;s website and the on-line retailer has previously stored the consumer&#39;s credit card number the consumer need only indicate that he or she wishes to “pay now” in order to make complete use of the facilities of the present invention. 
         [0052]    In any case, once assembled, the consumer&#39;s request is forwarded by the access controller  51  to the authenticator  52  which will generally first undertake to determine whether the credit card for which the end user  34  has requested access is recognized at the service provider  36 . To this end, the authenticator  52  may access the user database  58 , as generally shown in  FIG. 8 , to determine whether the provided credit card number can be located in the resource table  88  of the user database  58 . If not, the authentication process  46  may be terminated with or without notice to the end user  34  or an appropriately updated webpage  75  may be generated to prompt the end user  34  for correction of the unrecognized identifying information and resubmission of the request. If, on the other hand, the provided credit card number is recognized the authenticator  52  will proceed to establish a new transaction record in the transaction table  86  of the transaction database  59 , as generally shown in  FIG. 9 . As will be appreciated by those of ordinary skill in the art, the previously created transaction reference may be used as the TRANSACTION_ID for the newly created record or, if no transaction reference was previously created the TRANSACTION_ID now created for the new transaction record may be considered the transaction reference for the transaction. In any case, transaction parameter records may then be created in the transaction parameter table  87  of the transaction database  59  in order to collect and store information pertinent to the continued processing of the transaction such as, for example, the unique RESOURCE_ID by which the identified credit card is known in the user database  58 , the amount of the requested payment or the like. Still further, the unique USER_ID by which the tentatively identified consumer is known in the user database  58 , as may be determined (if not provided as part of the forwarded request) with reference through the resource use table  99  to the user table  85  of the user database  58 , should also be stored in the transaction parameter table  87  of the transaction database  59 . 
         [0053]    With the end user  34  and the resource for which the end user  34  requests access both identified and logged to the transaction database  59 , the authenticator  52  next undertakes to direct the generation of an appropriate challenge message  94 , the response to which may be used to positively authenticate the identity of the presently tentatively identified end user  34 . In order to best understand the challenge and response protocols of the present invention, however, it is instructive to expressly define a number of terms. To that end, a “string” shall for purposes of the present invention be expressly defined to mean “an ordered sequence of any subset of symbols selected from a set of symbols wherein each symbol forming the set may be represented in both a format that may be perceived by an end user  34  and a format that may be recognized by software or hardware,” e.g. the set of all alphabetic and numeric characters in the English language, each of which, of course, may be presented in written or audible form for perception by an end user  34  and also may be encoded as binary data for recognition by software or hardware. A “null character” shall for purposes of the present invention be expressly defined as “a specially designated symbol intended to indicate the absence from a sequence of a single symbol,” e.g. a box with an X character, as shown in the drawings forming a part of this specification, any symbol (such as a particular number, particular letter, an asterisk, an underscore or the like) designated at implementation to be defined as being a null character or a blank space. “Random” as applied to the characterization of a string shall for purposes of the present invention be expressly defined to mean that the symbols of the string are arranged in an order that is not readily predictable. 
         [0054]    In accordance then with the authentication system  30  and method  46  of the present invention, the primary challenge is generated to include a random string comprising a plurality of symbols wherein at least one of the symbols of the string is a null character, such a random string being referred to herein as a challenge string  49 . Additionally, each end user  34  (and, if desired, any administrative user) will have stored in the user table  85  of the user database  58  a private string, which is a user selected or assigned (depending on implementation preferences) string comprising symbols of the same set as used for generating the challenge string  49  but most preferably excluding use of the null character. A private string is generally only known to the user with which it is associated and the service provider  36  and, in a critical aspect of the present invention, a private string is never required to be openly passed through the user interface  105 . In any case, as will be better understood further herein, a user will formulate a response to a challenge string  49  by using the symbols of the user&#39;s private string to replace the null character or characters of the challenge string  49  to formulate a response string. In this manner, the response string may be passed through the user interface  105  without risk of interception of the private string and, accordingly, a system of readily established single use “passwords” is presented. Additionally, as also will be better understood further herein, the authentication system  30  and method  46  of the present invention may be implemented such that the protocol for creating a response string from a challenge string  49  is standardized in advance or, in the alternative, instructions  93  may be provided with the challenge message  94  or inferred from the manner of delivery of the challenge or circumstances of the use. For example, the user may be directed to formulate the response string using only numbers of the private string or may assume that only numbers should be used when entering the response string into a limited keypad  95  such as depicted in  FIG. 7 . Further, instructions  93  may be given to use every second or third symbol of the private string, to begin with a certain symbol of the private string, to take symbols from the private string in reverse order, or any combination of these and similar instructions  93 . Still further, the user may be instructed as standard procedure or by challenge message  94  to repeat usage of certain symbols of the private string or the entire private string in order to respond to a challenge string  49  with more null characters than symbols available in the user&#39;s private string and/or simply as a matter of choice by the service provider  36 . 
         [0055]    Returning then to the example use of the authentication system  30  of the present invention it is noted that in the most preferred embodiment of the present invention prior to directing the generation of a challenge message  94  the authenticator  52  evaluates all available information that may impact the ability of an end user  34  to readily receive a particular challenge message  94  and/or to readily respond to a particular challenge message  94  and, additionally, determines whether any special security requirements may exist for access to the particular resource. In particular, the authenticator  52  will preferably obtain from the channel table  111  of the user database  58  channel data indicating the type of communication channel that will be utilized to transmit the challenge message  94 . Additionally, the user attribute table  92  of the user database  58  may indicate whether the end user  34  suffers any disability that would impact the manner of response and/or the resource attribute table  89  of the user database  58  may indicate any special resource dictated security requirements, such as minimum length or desired complexity for a response string. Additionally, the authenticator  52  may also consider any limitations of the user interface  105 , such as being limited to entry of numeric characters only. In any case, the authenticator  52  will determine the characteristics that should be exhibited by the challenge string  49 , including the manner of issuance, and will then instruct the challenge manager  53  to initiate issuance of a challenge message  94 . 
         [0056]    At this point it is noted that in accordance with an extension of the present invention, the primary challenge (comprising the challenge string  49  and any necessary response instructions  93 ) may be supplemented with the provision of a test designed to detect the existence of a spoofing type deception. In particular, the present invention contemplates the use of a dynamically selected image  112  for the conduct of this test. Although the particular conduct of this test will be described in greater detail further herein, it should at this time be noted that in an implementation wherein such a test will be required the challenge manager  53  will generally at this point in the process obtain from the image database  107  image data identifying the selected image  112  and its location on a fileserver and will store the obtained image data in the image table  113  of the transaction database  59 . In any case, the challenge manager  53  will continue to by obtaining from the random sequence generator  54  a challenge string  49  generated to meet the requirements established and communicated by the authenticator  52 . With the challenge string  49  generated and any image data obtained, the challenge manager  53  will proceed to construct the challenge message  94  which will at least comprise the challenge string  49 , any special response instructions  93  and a copy of the image file if required. With the challenge message  94  assembled, the challenge manager  53  queues the challenge message  94  by providing the messaging gateway  60  with the challenge message  94 , the type of communication channel to be utilized and the CHANNEL_ID for the channel. For example, if the challenge message  94  is to be sent by SMS text message  79 , the challenge manager  53  will inform the messaging gateway  60  that the challenge message  94  is to be transmitted by SMS text message  79  and will provide the messaging gateway  60  with a telephone number for a SMS text capable user device. 
         [0057]    At this juncture it is noted that it is considered critical to the present invention that the challenge message  94  be transmitted through a discrete channel, which is herein defined as being a communication channel not readily identifiable by information submitted by an end user  34  in making a request for access to a secured resource. For example, if the end user  34  chooses to utilize his or her electronic mail address as a user or resource identification, the schema for the user database  58  and/or the authenticator  52  should ensure that the challenge message  94  is not transmitted by electronic mail to the same electronic mail address. Likewise, an end user  34  requesting access to a secured resource using his or her mobile telephone number as an identifier will not be able to receive a challenge message  94  by SMS or standard text message  79  or synthesized voice call to the same mobile telephone number. That said, however, it is noted that the schema as depicted in  FIG. 8  contemplates that a single user may have more than one possible message channels assigned. As a result, a channel may be discrete for some requests, but not for others depending upon the information provided by the end user  34  in making a particular request. 
         [0058]    Referring to  FIG. 11  in particular, there is shown a typical simple challenge message  94  as may be transmitted to an end user  34  through an SMS text enable smart phone or like mobile device  78 . Following with the presented example, it is noted that in an optional but useful feature of the present invention the challenge message  94  may also include information helpful to the consumer in making a response. For example, the challenge message  94  depicted in  FIG. 13  includes the name of the on-line service provider, the purchase amount for which the user requests access to his or her secured resource and also the client reference used by the on-line service provider. 
         [0059]    Finally, the authenticator  52  obtains the consumer&#39;s private string from the user table  85  of the user database  58 , as shown in  FIG. 8 , and then submits the challenge string  49  (along with any special instructions  93 ) and the private string to the validation tool  55 , which in turn determines the correct response string. The determined correct response string is then assigned as the key string for the transaction and stored in the key string table  97  of the transaction database  59 . At this time, a timestamp may also be entered into the transaction table  86  of the transaction database  59  in order to provide a reference by which may be calculated a timeout event for the validity of the key string (response string submitted as an authentication credential). 
         [0060]    Before turning the example to detailed discussion of the steps  48  implicated in validating the purported access right of the user requesting access to the secured resource, however, attention is directed to  FIGS. 12 and 13 , each of which depict some variation of possible challenge messages  94  and/or additional detail regarding the presentation to the consumer of an image  112  for use in detecting a possible spoofing type deception. In  FIG. 12 , in particular, an image  112  is shown as being presented with the challenge string  49  as part of the challenge message  94 . As indicated by the example instruction text included with or as part of the challenge message  94 , the consumer is directed to look for a corresponding image to be displayed on the website of the on-line retail store and to not enter a response string unless the correct image is observed.  FIG. 13 , on the other hand, shows in particular one simple example of the many previously discussed possibilities for providing special instructions  93  in connection with the issuance of a challenge message  94 . In the depicted case, the consumer is directed to respond to the challenge string  49  using only numbers from his or her private string. As will be appreciated by those of ordinary skill in the art, this instruction  93  will be particularly beneficial when it is known that the consumer will be forced to enter the response string through a limited input modality such as, for example, the simple keypad  95  depicted in  FIG. 7 . 
         [0061]    Turning the example now to detailed discussion of the steps implicated in validating the purported access right of the user requesting access to the secured resource, it is first noted that an end user  34  of the present invention will necessarily formulate a response string corresponding to a challenge string  49  outside of the hardware and/or software provided as part of the authentication system  30  of the present invention. That said, the validation steps begin with the consumer using his or her web browser  69  to first navigate to the uniform resource locator (“URL”) of a payment confirmation webpage  75  for the on-line retailer (the service provider  36 ). As is otherwise conventional, the consumer&#39;s web browser  69  will send a page request to the on-line retailer&#39;s web server  66  where a hosted page processor  64  will create and send back to the consumer&#39;s web browser  69  the requested “payment confirmation” webpage  75 , making use of the on-line retailer&#39;s database management system  57  to retrieve stored information pertaining to the consumer, the transaction or the like. As shown in  FIG. 14 , the requested page  75  may simply comprise a simple form through which the consumer may input his or her formulated response string and then select the depicted “confirm” button. As will be appreciated by those of ordinary skill in the art, this simple example assumes that the consumer has remained on the website of the on-line retailer such that the transaction reference remains known to the page processor  64  and also that no test designed to detect the existence of a spoofing type deception will be presented. Similarly, the requested page  75  as depicted in  FIG. 15  also assumes that no test designed to detect the existence of a spoofing type deception will be presented, but contemplates that the consumer may have left and returned to the website for completion of the purchase transaction. As will be appreciated by those of ordinary skill in the art in light of this exemplary description, the depictions of  FIGS. 14 and 15  may be appropriate for responding to the challenge as depicted in  FIG. 11 . For purposes of this continuing example, it shall be assumed that the consumer&#39;s private string is 2F46DAH525. As a result, the correct response string for the challenge string  49  of  FIG. 11  would be 24FA63462B, which would be entered by the consumer. With the response string entered, the consumer&#39;s web browser  69  submits the data to the on-line retailer&#39;s web server  66  where the hosted page processor  64  may validate the form data for technical completeness and accurate formatting. Assuming that the submitted data is technically correct or is subsequently made technically correct, the page processor  64  submits the consumer&#39;s response string to the access controller  51  hosted on the on-line retailer&#39;s application server  50 . 
         [0062]    As shown in  FIG. 16 , however, the requested page  75  may comprise a slightly more complex form through which the consumer may be required to enter the transaction reference for the transaction although, as shown in  FIG. 16 , the transaction reference data may be pre-populated if the consumer has not left the website. As will be appreciated by those of ordinary skill in the art, this form contemplates that the consumer may want to address a different transaction than presently being handled by the webpage  75  or that the consumer has left and returned to the website for completion of the purchase transaction. Additionally, this exemplary form contemplates that a test designed to detect the existence of a spoofing type deception may or may not be presented. In any case, once the consumer is satisfied that the desired transaction reference is shown the consumer will then select the depicted “continue” button, whereafter the consumer&#39;s web browser  69  submits the data to the on-line retailer&#39;s web server  66  where the hosted page processor  64  may validate the form data for technical completeness and accurate formatting. Assuming that the submitted data is technically correct or is subsequently made technically correct, the page processor  64  submits the consumer&#39;s response string to the access controller  51  hosted on the on-line retailer&#39;s application server  50 . Once received by the access controller  51 , the client reference will be utilized to retrieve the stored request data from the transaction database  59  and the access controller  51  will determine whether a test designed to detect the existence of a spoofing type deception should be presented. If not, the access controller  51  will so inform the page processor  64  which, in turn, may then update or otherwise create and send back to the consumer&#39;s web browser  69  a “payment confirmation” webpage  75  like that of  FIG. 14 , whereafter the consumer continues as previously discussed. 
         [0063]    If, on the other hand, the access controller  51  determines that a test designed to detect the existence of a spoofing type deception should be presented the request handler  51  will retrieve from the image table  113  of the transaction database  59  the previously stored image data associated by the transaction reference with the present transaction. As previously noted, the challenge manager  53  will have previously sent to the consumer, as part of a challenge message  94 , an image file. Rather than utilizing an actually image file at this stage, however, the preferred implementation of the test comprises the access controller  51  retrieving the file location for a copy of the image matching the image file transmitted as part of the challenge message  94  and which file location (external web address) has preferably been made temporary on a publicly accessible fileserver associated with the service provider  36 . The page processor  64  will then create a page  75  such as depicted in  FIG. 17 , wherein the webpage  75  presents the image  112  by linking to the external web address (the temporary file location) at which the image  112  is hosted. As will be appreciated by those of ordinary skill in the art in light of this exemplary description, the depiction of  FIG. 17  may be appropriate for responding to the challenge as depicted in  FIG. 12 . Assuming still that the consumer&#39;s private string is 2F46DAH525, the correct response string for the challenge string  49  of  FIG. 12  would again be 24FA63462B, which would be entered by the consumer. 
         [0064]    As previously discussed, the preferred implementation of the test designed to detect the existence of a spoofing type deception comprises providing a web link pointing to a copy of the image file on a fileserver associated with the service provider  36 , which file location may then be made temporary. By making the file location temporary, the file can be removed or restricted and/or replaced with a warning image once accessed through the web link. In this manner, if the consumer has accidently navigated to a spoofed website conducting a man-in-the-middle type deception in particular, the bad actor will in the course of accessing the true on-line retailer&#39;s website access the image link. In the unlikely case that the bad actor is able to retrieve and replicate the link for presentation to the consumer, however, the image  112  will have been removed or replaced by the time that the consumer links to the web address for the image. In this case, as shown in  FIG. 18 , the consumer will see the bad actor generated webpage with the prominently displayed warning image  114 . 
         [0065]    Finally, as shown in  FIG. 19 , the consumer may be required to actually select one image  112  from a plurality of images  115  at the same time as he or she is required to enter his or her response string. In such a case, the image selection will be transmitted with the response string and will form a part of the overall response to be evaluated by the authenticator  52 . As will be appreciated by those of ordinary skill in the art, this embodiment serves to ensure that a careless consumer does not fail to carefully check for the required image  112 . 
         [0066]    In any case, with the response string entered, the consumer&#39;s web browser  69  submits the data to the on-line retailer&#39;s web server  66  where the hosted page processor  64  may validate the form data for technical completeness and accurate formatting. Assuming that the submitted data is technically correct or is subsequently made technically correct, the page processor  64  submits the consumer&#39;s response string to the access controller  51  hosted on the on-line retailer&#39;s application server  50  whereafter the response message is submitted to the authenticator  52  hosted on the service provider&#39;s application server  50 . 
         [0067]    The authenticator  52  will then direct the validation tool  55  to evaluate the response string based upon the transaction reference for the response message. The validation tool  55  will access the key string table  97  of the transaction database  59  to retrieve the key string associated with the particular transaction reference and will evaluate the submitted response string against the retrieved key string taking into account, if appropriate for the particular implementation, the passage of time. Additionally, in a case where the selection of a particular image also forms part of the required response in addition to the response string, the validation tool  55  will also determine whether the correct image was selected by the end user  34 . In any case, the validation tool  55  will then report the result of the evaluation to the authenticator  52 . If the evaluation fails, the process  48  will terminate and the failure will be reported to the access controller  51 , which in turn will block the end user  34  from access to the requested secured resource. If, on the other hand, the evaluation passes the authenticator  52  will report the authenticated status to the access controller  51 , which in turn will allow the access as requested by the end user  34 . 
         [0068]    Finally, it is noted that in previously describing the manner in which the authentication system  30 , implemented according to the exemplary example presented, may determine an otherwise unknown unique USER_ID for the consumer from knowledge of the unique RESOURCE_ID for an identified secured resource (the credit card number in the presented example) it was stated that from the resource table  88  (holding the unique RESOURCE_ID for the credit card) the user table  85  (holding the unique USER_ID for the consumer) could be accessed through the resource user table  99 . While those of ordinary skill in the art will recognize that the foregoing example use could have been carried out with an implementation omitting the intermediary resource user table  99 , provision of the resource user table  99  as join table for the resource table  88  and the user table  85  establishes a many-to-many relationship between the records of the resource table  88  and the user table  85 , whereby additional functionality is imparted to the authentication system  30  and method  46  of the present invention. In particular, by allowing a single secured resource to be associated with a plurality of end users  34 , joint or other plural access control may be established for the secured resource. 
         [0069]    For example, a parent of child patient presenting for treatment at a medical clinic may provide the child&#39;s Social Security Number to the clinic for use by the clinic in requesting access to the child&#39;s electronic medical records accessible by either one of two passwords held one each by two parents. In this case, the authentication system  30  implemented to provide for multiple user association with a single secured resource may simply look up each parent end user  34  associated with the child&#39;s identified medical record (secured resource) and send a separate challenge message  94  to each, storing the appropriate key strings in separate records of the key string table  97  of the transaction database  59 , each record being connected by TRANSACTION_ID to the single transaction record established in the transaction table  86  of the transaction database  59  for the request for access to the child&#39;s medical record. As will be appreciated by those of ordinary skill in the art, the validation tool  55  of the authentication system  30  will evaluate a received response string against each key string associated with the transaction and will find valid a response string matching either. By way of further example, and without limitation, it should be appreciated, especially in light of this exemplary description, that this aspect of the present invention will have broad application, including for use in authorizing transactions against shared credit card or banking accounts, accessing shared on-line service accounts, deactivating an alarm system or accessing a computer controlled door for a home, business or other facility shared by many occupants or similar applications. Likewise, this aspect of the present invention may also be implemented such that a correct response string must be received from a plurality of end users  34  in order for the authentication system  30  and process  46  to authenticate a particular request for access to a secured resource. In this manner, “two-person control” and like security protocols may be readily handled within the scope of the present invention. 
         [0070]    While the foregoing description is exemplary of the preferred embodiment of the present invention, those of ordinary skill in the relevant arts will recognize the many variations, alterations, modifications, substitutions and the like as are readily possible, especially in light of this description, the accompanying drawings and claims drawn thereto. For example, those of ordinary skill in the art will recognize that a special program logo, such as the exemplary “Secure Payment System Enabled!” logo depicted in various of the figures may be utilized to signal to a potential end user  34  that system, facility or the like for which the end user  34  desires access has implemented the teachings of the present invention. Likewise, those of ordinary skill in the art will recognize that a special program magnetic card or the like may be implemented in order to enable card swipe type initiation of a request for access. In this case, of course, the magnetic card may be encoded with an identification code for the user including no confidential or sensitive information, but preferably useful only in connection with identifying the end user  34  to an authentication system  30  implemented in accordance with the teachings of the present invention. In any case, because the scope of the present invention is much broader than any particular embodiment, the foregoing detailed description should not be construed as a limitation of the scope of the present invention, which is limited only by the claims appended hereto.