Abstract:
A system for making a purchase by a customer from a merchant, wherein an electronic message represents an instruction for payment from an account with a financial institution, includes a method of: associating a public key with identity information regarding the account; receiving by the merchant both encoding information for the electronic message and the identity information; forwarding by the merchant the electronic message, encoding information, and identity information; upon receipt of the electronic message, the encoding information, and identity information, retrieving the public key associated with the identity information; and determining a validation result as a function of the electronic message, the encoding information, and the retrieved public key. Upon successful validation, an account authorization is performed or payment from the account is made.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of and claims the benefit under 35 U.S.C. §120 to the application to Wheeler et al. entitled “Account Authority Digital Signature (AADS) System”, Ser. No. 09/189,159, filed on Nov. 9, 1998, pending. 
    
    
     FIELD OF THE INVENTION 
     The field of the invention relates to digital signatures, and particularly, using digital signatures to reliably identify a sender and the accuracy of an electronic message without using certification authorities. 
     BACKGROUND OF THE INVENTION 
     The increase in electronic commerce has increased the focus on security of the electronic transactions using this medium of commerce. In the world of computer transactions and electronic contracts, there is no face-to-face acknowledgement to identify the consumer or other person wishing to perform the transaction. As institutions become more reliant on computers, they have modified their business infrastructure (i.e., their “business process”) in an attempt to keep up with electronic commerce. The business process of an institution includes the methods used to interact with a customer (e.g., how transactions occur, what information is required from the customer, help desks to support the customer), the information contained in customer accounts, the databases used and how they are modified by the institution, and personnel training. 
     Institutions and persons desiring to utilize electronic commerce are faced with several issues regarding electronic transactions. The first issue is whether the person requesting the transaction is who they say they are (“identification”). And the second issue is whether the requested transaction is actually the transaction intended to be requested (“accuracy”). In other words, whether the requested transaction has been compromised, either fraudulently or through transmission errors, during the course of transmitting and receiving the request. 
     To address the identity, of the person requesting the transaction, current financial business processes bind information in accounts to authenticate non-face-to-face transactions. For example, an account holder&#39;s mother&#39;s maiden name, a personal identification number (PIN), and a social security number have all been used and integrated into the current financial infrastructure to aid in reliably identifying someone requesting a non-face-to-face transaction. 
     To address the accuracy of the electronic message being sent and the identity of the person sending the electronic message, digital signatures are utilized. Digital signatures are used with electronic messages and provide a way for the sender of the message to electronically “sign” the message as a way of providing proof of the identity of the sender and the accuracy of the message. In a digital signature system, a sender digitally “signs” the message using a private key (encryption software used to create a digital signature). The receiver validates the sender&#39;s digital signature by using the sender&#39;s public key (software used to decrypt the digital signature) sent to the receiver by the sender. 
     While, digital signatures provide some assurance of accuracy for the message and the identity of the sender, they are also subject to security risks. These risks include compromised private and public keys or merchant fraud. To address the security risks and validate the digital signatures, computer technology has developed “certification authorities” to be used in a Certificate Authority Digital Signature (“CADS”) system. In a CADS system, certification authorities are third parties that essentially “vouch” for the validity of a digital signature&#39;s public key and, hence, the validity of the digital signature. 
     However, certification authorities used in the CADS system come with inherent risks, such as an expired certification authority and a compromised private key, which affect the entire public key infrastructure. In addition, the increased reliability provided by certification authorities does not easily combine with the business process currently established. 
     Therefore, there is a need in the art for a method to increase the reliability of electronic transactions while not imposing significant modifications on the business processes already in place. 
     SUMMARY OF THE INVENTION 
     The present invention meets the needs described above by providing a method of reliably identifying the sender of an electronic message and determining the accuracy of an electronic message while utilizing the current standard business processes. 
     The current financial infrastructure can extend existing business processes to support high integrity electronic commerce by implementing the present invention. One embodiment of the present invention can be implemented as the Account Authority Digital Signature (AADS) system. The AADS system uses digital signatures along with validation procedures that can be implemented within current institutional business processes to identify a sender of an electronic message and determine the accuracy of the electronic message being sent. 
     The present invention simplifies its implementation by leveraging existing account infrastructures and by operating within existing business processes. In addition, the present invention utilizes electronic signatures in the business process for increased reliability. Yet, however, the present invention does not rely on third parties (i.e., certification authorities) for authorization, thereby avoiding any security risks or other systemic risks associated with the third parties. And finally, no new databases need to be developed to implement the present invention. 
     Generally described, the identity of a sender of an electronic message is validated by using sender validation information along with other sender identity information stored at an institution&#39;s or person&#39;s computer system and applying the sender validation information to the encoding information received by the computer system. The sender validation information is the sender&#39;s public key in a digital signature system. 
     The present invention utilizes the accuracy of electronic encoding, e.g., digital signatures, and provides a method to incorporate them into the current business processes. An institution records an encoding key (public key) and associates it with account information from the sender. This initial recording may be performed using any of the validation procedures utilized today by a business institution, for example, when the sender is opening a new account and must show proof of identity. 
     After the initial validation of the encoding key, validating future electronic transactions occur by including encoding information that can be deciphered using the valid encoding key initially stored. To validate an electronic transaction, the sender sends the electronic transaction message, the encoding information and sender identity information to the person or institution from which the sender desires validation. Having received this information, the computer system automatically retrieves the encoding information stored in the computer system that is associated with the sender identity information. The computer system then validates the electronic transaction message by applying the retrieved encoding key to the encoding information and analyzes the electronic transaction message to validate the identity of the sender and the accuracy of the message. 
     This validation may be performed in a digital signature system by applying a hashing algorithm to the electronic message and comparing the results to the results of applying the public key to the digital signature received. 
     The encoding information may be entered into a terminal by means of a smart card or by means of another computer system. The encoding information, electronic message and sender identity information may be sent to the computer system performing the validation via a closed network or via an open network, such as the Internet. 
     These and other advantages of the present invention will be more clearly understood and appreciated from a review of the following detailed description of the disclosed embodiments and by reference to the appended drawings and claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram depicting an exemplary debit card system as it exists in the prior art. 
         FIG. 2  is a block diagram depicting a Certification Authority Digital Signature (CADS) system of the prior art. 
         FIG. 3  is a block diagram depicting the digital signature process. 
         FIG. 4  is a block diagram depicting the effect of a security breach in the existing debit card system. 
         FIG. 5  is a block diagram depicting the effect of a security breach in the CADS system of  FIG. 2 . 
         FIG. 6  is a block diagram of an exemplary computing environment in an embodiment of the present invention. 
         FIG. 7  is a block diagram of the components of an embodiment of the present invention. 
         FIG. 8  is a block diagram depicting an embodiment of the present invention as it is implemented using a financial institution, a merchant and a customer. 
         FIG. 9  is a flowchart depicting the steps performed in implementing an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention provides a method for reliably identifying the sender of an electronic method and determining the accuracy of an electronic message while utilizing current standard business processes. 
     Electronic commerce is currently used and implemented in several existing systems. The conventional debit card system is one example. The debit card system attempts to identify the sender of the electronic message (e.g., the message of “Withdraw $200 from my account”) while working in the current business processes. In other words, it utilizes a PIN as merely another validation mechanism. However, the debit card system does not verify the accuracy of the message. In addition, because of the security risks, the debit card system is not utilized on an open network, such as the Internet, thereby limiting it&#39;s access to electronic commerce. 
     The Certification Authority Digital Signature (CADS) system of  FIG. 2  is another example of a system for implementing electronic commerce. The CADS system provides message accuracy and may be used in open networks, such as the Internet. However, CADS also has inherent systemic risks and requires reliance on third parties to “authorize” the digital signature of the sender of the electronic message. In addition, the CADS system is difficult to implement using standard business processes utilized today. 
     Both the debit card system and the CADS system can have severe consequences in the event the security of either system is compromised. The debit card and CADS systems, as well as the security risks associated with each, are discussed further in  FIGS. 1-2  and  3 - 4 . 
     Turning now to the figures,  FIG. 11  is a block diagram depicting a conventional debit card system as it exists in the prior art. Typically, a customer enters account information and a personal identification number (PIN) into a terminal  100 . The account information is generally stored on magnetic tape attached to a card that is given to the customer so that the customer may enter it into the terminal  100 . Upon entering the account information and the PIN, the terminal then formats this data and sends it across a closed network  105  to the main computer  110  that validates the PIN with an associated account that has been entered by the customer. The PIN was stored in a field along with other account information in the main computer previously. The PIN is typically associated with the customer when the account is established but generally not through the network  105 . Normal procedures provide for the customer to validate his/her identity when the account is opened or prior to associating a PIN to the customer&#39;s account. This would verify to the institution that the person establishing the account is who they claim to be and increases the reliability that the when the PIN is used, the customer assigned the PIN is the person using it. 
     Upon validating the PIN with the associated account, the main computer  110  then accepts or rejects the PIN and sends the results back through the network  105 . The terminal, having received the acceptance or rejection, then either continues to process the customer&#39;s transaction or denies customer access to the account. 
     The PIN used in the debit card system is the same for all transactions. In other words, no matter what transaction the customer wishes to initiate with the main computer, i.e., regardless what message is sent to the main computer by way of the terminal, the PIN stays exactly the same. 
     The terminal  100  used in the debit card system is a basic terminal that is used to format the entered information to send to the main computer  110 . In addition, the terminal  100  may perform some function such as dispensing cash or other functions specific to the account. However, the terminal  100  is generally a dumb terminal only used to facilitate the customer&#39;s interaction with the main computer  110  (i.e., the terminal is not typically used for purposes other than to interact with financial institutions). The terminal  100  communicates with the main computer  110  by network  105 . 
     The network  105  used in the debit card system is typically a closed network that is set up specifically for use between the terminal  100  and main computer  110 . While it is possible that others may break into the network, generally, the network  105  is not used for other traffic other than messages sent between the terminal  100  and main computer  110 . 
     The main computer  110  used in the debit card system is generally housed at the institution containing the account and contains all the records for the institution relative to the account and the PIN. When the account is initially set up, all information required to process this transaction as well as potentially other transactions within the institution is validated. For security reasons, the required information was validated in either face-to-face or in some other mariner that can validate the customer&#39;s identity. Consequently, there is a direct validation of the account to the customer when the account is established. As stated earlier, the business processes set up in many financial institutions today follow this model. These processes include manuals, computer databases and records, held desks and personnel training. 
       FIG. 2  is a block diagram depicting a Certification Authority Digital Signature (CADS) system of the prior art. The CADS system relies on the digital signatures and traditional public key infrastructure in issuing certificates that are signed by a certification authority (see  FIG. 3  regarding a description of digital signatures and their usage). A certification authority attests to the validity of the public key and sometimes, depending on the authority, checks the validity of the private key and the identity information of the entity that the certificate is issued to. The sender then sends the certificate, which in this case is a digital signature incorporating the sender&#39;s digital signature, issued by the certification authority; the message; and the sender&#39;s public key to the receiving party. The intent is that the receiving party will trust the certification authority&#39;s verification and also will be able to validate the certification authority&#39;s digital signature and the sender&#39;s message using the contents of the information sent by the sender and a public key of the certification authority. 
     In  FIG. 2 , the sender  201  creates a digital signature using the sender&#39;s message  225  (Additional discussion on creation of a digital signature is provided below in relation to  FIG. 3 ). Prior to sending the message to the receiver  242 , it is preferable to validate the sender&#39;s message and therefore the sender submits the message and the digital signature to a certification authority. The intent of the certification authority is to confirm that the identified sender is sending the message. Continuing with  FIG. 2 , the sender then has the digital signature “authorized’ by a Certification Authority 1 (CA1)  205 . The CA1 has, in advance, identified the public key associated with the sender. Therefore, the CA1  205  checks the current digital signature with the public key of the sender. Upon a successful check, the CA1  205  then creates a digital signature by digitally signing the sender&#39;s digital signature. 
     An example of a certification authority includes certifying the identity of specific banks. However, as there are no rules or laws regarding who is a certification authority and who is not and, in some instances, the receiver may not “trust” the certification authority. The receiver might be a large scale institution that does not trust a certification authority that deals with just a few customers or small institutions. Specifically, the receiver may not trust that the security is as high as it expects from the certification authority. Therefore, the receiver would require a higher-level certification authority. In cases like this, the digital signature of the first certification authority also needs to be authorized in like manner. This is depicted in  FIG. 2  by CA1 sending its digital signature and the sender&#39;s digital signature to certification authority 2 (CA2)  210 . CA2 is, in essence, an authority that confirms the identity of other first “level” certification authorities. In the example provided, CA2 may confirm the identity of a financial institution versus just a bank as in CA1. 
     This additional certification authority may still not rise to the level of security required by the receiver so yet another certification authority may be necessary. This is depicted by CA2  210  creating a digital signature using, i.e., by digitally signing, CA1&#39;s  205  digital signature and sending CA2&#39;s digital signature with CA1&#39;s digital signature on to CA3  215 . CA3  215  could be just another higher-level certification authority that checks all institutions. And as is apparent, this hierarchy of certification authorities could continue ad infinitum. However, at some point, the sender and receiver are satisfied with the level of certification authorities and, in  FIG. 2 , ends with CA3  215 . CA3&#39;s digital signature is created by digitally signing CA2&#39;s digital signature. The sender  201  then attaches the digital signatures  235  to the sender&#39;s message  225  along with the sender&#39;s public key  230  into a complete message block depicted by  220 . The space required for the digital signature may be significant in relation to the message. Generally, the classic electronic transaction message comprises 80 bytes and the sender&#39;s digital signature comprises 60 bytes. However, for each certification, it requires another 2,000 bytes. The size of the message the sender is sending over the network  240  is increased substantially by using certification authorities. The sender then having combined the message  225  the sender&#39;s public key  230 , and the digital signatures  235 , sends this complete packet over the network  240  to the receiver  242 . 
     The receiver now has to validate the sender&#39;s message to ensure that the authentic sender is sending the message and not a third party using the sender&#39;s identity. Having received the complete packet  220 , the receiver  242  then begins applying public keys to the digital signatures received in the packet. Typically, the receiver will already have the public keys of the certification authorities used by the sender. In cases where it is not clear, the sender should also send the public keys to the receiver. 
     In the instance shown in  FIG. 2 , because CA3 was the final certification authority, the receiver then applies CA3&#39;s public key to CA3&#39;s digital signature of the digital signatures  235  that were received in the packet  220 . Applying CA3&#39;s public key to the CA3&#39;s digital signature verifies CA2&#39;s digital signature. Now having CA2&#39;s digital signature  245 , the receiver applies CA2&#39;s public key to CA2&#39;s digital signature  245  to verify that CA1&#39;s digital signature  250  is unmodified. The receiver then must apply CA1&#39;s public key to CA1&#39;s digital signature to verify that the initial sender&#39;s digital signature  255  is unmodified. 
     While it is shown that this process is performed three times because there have been three certification authorities, it will be recognized that this process would occur as many times as there are certification authorities used for the sender&#39;s message. It is clear that this process also adds significant overhead processing to the validation of the sender&#39;s identity. Particularly with the more certification authorities used, the processing and resources required purely for the task of validating the sender is increased dramatically. 
     Finally arriving at verification  255  of the sender&#39;s digital signature, the receiver then validates  244  the sender&#39;s message  225 . The receiver does this by using the sender&#39;s message  225 , the sender&#39;s public key  230  that had been sent in the initial packet  220 , as well as the sender&#39;s verified digital signature  255  that was created from this process of certification authority validation just described. The receiver uses all these components to then validate at  244  the sender&#39;s digital signature. The receiver may send back the results of the validation, or if the validation was successful, act on the message sent. 
     While the CADS system depicted in  FIG. 2  provides some degree of reliability confirming the sender&#39;s identity, standard business processes are not equipped to deal with these kind of certification authority validation procedures. 
       FIG. 3  depicts how a message is validated using the digital signature process. Initially, the sender creates a message  300  and applies a hashing algorithm to the message  300  to create a modified message  305 . Because of the hashing algorithm, the modified message typically is a much smaller version of the actual message itself. 
     The modified message  305  that is created using the hashing algorithm and the sender&#39;s message  300  is not only smaller, but is also unique to the message. In other words, as the message changes, the modified message will also change after applying the hashing algorithm. The modified message is then encrypted with the sender&#39;s private key. 
     The process of using a digital signature generally requires a private and a public key. These keys are typically obtained from software houses and developers that create encryption programs. The private key is used by the sender and only by the sender. To maintain the security, as the name implies, the private key is intended to be kept private to the sender and not for public dissemination. This is the only time in the process, i.e., applying the private key to the modified message  305  to create the digital signature  310 , where the private key is used. 
     The creation of the sender&#39;s digital signature described above in  FIG. 3  can be performed at the sender&#39;s local computer, or in some cases, on a smart card. The use of smart cards are well know to those skilled in the art. The end result of the sender&#39;s process is that the sender has created a digital signature. And as stated, this digital signature is message specific, i.e., if any letter or any component of the message was changed, this digital signature would also change. The digital signature is also specific to the individual sender, i.e., the private key encryption method is only for that sender. 
     The sender then sends the sender&#39;s message with a public key, if the receiver does not already have one, and the digital signature to a receiver (this “sending” process is not shown). The receiver then takes the received message  300 ′ and applies the same hashing algorithm described above for the sender to create the modified message  305 . Ideally, this should result in a modified message  305 ′ that is the same as the modified message  305 . The only case where the sender&#39;s and receiver&#39;s modified message is different is if the message was corrupted either by the sender after having applied the digital signature to it, by transmission errors or someone fraudulently intercepting the message and attempting to change its contents. 
     Still referring to  FIG. 3 , next the receiver then takes the received digital signature  310 ′ and applies the sender&#39;s public key to the digital signature. As implied, the public key is available for public use by the sender without losing any security of the sender&#39;s private key. The receiver then applies the public key to create the decrypted digital signature  315 . The decrypted digital signature  315  and the modified message  305 ′ are then compared by the receiver. If they both match and are identical, then the receiver knows that the message was encrypted with the sender&#39;s private key and was the same message that has been received. However, because it is not known for sure whether the sender&#39;s private key has been compromised (e.g., stolen), the receiver is still not absolutely sure that the sender identified in the message actually is the one who sent it. 
       FIG. 4  is a block diagram depicting the effect of a security breach (e.g., someone stealing someone&#39;s PIN and account info.) in the existing debit card system. In this case, the fraudulent customer enters account information and a PIN to a terminal  400  and requests a transaction. The same PIN is used for all transactions and the PIN typically is an easily remembered non-complex set of numbers and/or letters that can be entered by the customer. Once the PIN has been compromised for one message, that same PIN can be used for other messages that the fraudulent customer wishes to send. 
     The terminal  400  having received the account information and PIN from the fraudulent customer then, as expected, sends this fraudulent information on to the main computer  410  through the network  405 . The main computer  410  is not checking the message against the PIN. It merely receives the PIN and checks it against the account that has been stored already in the main computer  410 . If the fraudulent customer has done his job and has stolen the correct PIN, then the transaction will be validated and the acceptance will be passed on and the fraudulent customer will have access to someone else&#39;s account. 
     Another area of concern, not depicted in  FIG. 4 , is when a third party steals the customer&#39;s PIN by tapping into the network  405 . Since no encoding or encrypting is performed on the PIN, and since the same PIN is used for all messages, once someone has tapped into the network to obtain this information, that person is not required to perform any decryption on the message and can receive the PIN from the network. Once they have access to this PIN, they can then get into the customer&#39;s account and send any messages such as checking the account balance and withdrawing funds from the account. Having one PIN for all messages facilitates this type of security breach. 
       FIG. 5  depicts the effect of a security breach, i.e., the stealing of a certification authority&#39;s private key by a third party, in the existing CADS system. When a certification authority&#39;s private key is stolen by a third party, all messages certified by that authority are suspect because the third party, not the certification authority, may generate false messages which appear to be authorized by the certification authority. 
     In this case, an authentic sender is not attempting to send a message  500 , and in this example, CA1 has not applied any digital signature  505  because there is no message. But what has occurred is that there has been a security breach in the CA2. For example, CA2&#39;s private key has been stolen. In general, the effect of having the CA2&#39;s private key stolen is that it can then mask as any of the CA1s or senders relying on CA2 for certification even though they are not attempting to send any messages. In addition, a corrupted CA2 private key allows the creation of fictitious CA1s or senders that do not exist, yet will appear valid because they are certified by CA2. So, if a certification authority can validate that a specific merchant is requesting a transaction when that merchant is indeed not requesting a transaction, this facilitates the fraudulent use of the electronic commerce system. 
     Continuing with  FIG. 5 , a digital signature  520  of a sender is created for a fraudulent message  510  using a fraudulent public key  515 . The fraudulent sender&#39;s digital signature  520  then is purportedly digitally signed by CA1, and the compromised private key of CA2 is used to digitally sign the fraudulent CA1&#39;s digital signature, thereby authorizing CA1&#39;s digital signature. The CA1&#39;s and CA2&#39;s digital signatures then are sent to CA3 for validation. Because the private key of CA2 has been compromised, CA2&#39;s digital signature is validated by CA3 and, consequently, the digital signatures and fraudulent message block  525  are forwarded on to the receiver  536  over the network  535 . 
     The receiver then receives the fraudulent message  510 , the fraudulent public key  515 , and the digital signatures  521 . The receiver then runs through the process as described in  FIG. 2  to verify the digital signatures. The receiver applies CA3&#39;s public key, to CA3&#39;s digital signature  530  and verifies  540  that CA2&#39;s digital signature is unmodified. It then applies CA2&#39;s public key to CA2&#39;s digital signature and verifies  545  that the fraudulent digital signature for CA1 is unmodified, even though CA1 has not digitally signed this message. The receiver then applies CA1&#39;s public key to what appears to be a legitimate digital signature of CA1, and verifies  550  that a fraudulent digital signature of the fraudulent sender is unmodified. This is the case even though the sender has not created a message, nor has CA1 validated it in any manner. The receiver, using the fraudulent digital signature verified at  550  and the fraudulent public key  515 , then validates  537  the sender&#39;s purported message. 
     The present invention addresses the security needs identified above by providing a method of reliably identifying the sender of an electronic message and determining the accuracy of an electronic message while utilizing the current standard business processes. Below is a description of various embodiments of the present invention. 
     Exemplary Operating Environment 
       FIG. 6  and the following discussion are intended to provide a brief, general description of a suitable computing environment in which the invention may be implemented. While the invention will be described in the general context of an application program that runs on an operating system in conjunction with a personal computer, those skilled in the art will recognize that the invention also may be implemented in combination with other program modules. Generally, program modules include routines, programs, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Moreover, those skilled in the art will appreciate that the invention may be practiced with other computer system configurations, including hand-held devices, multiprocessor systems, microprocessor-based or programmable consumer electronics, minicomputers, mainframe computers, and the like. The invention may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote memory storage devices. 
     With reference to  FIG. 6 , an exemplary system for implementing the invention includes a conventional personal computer  20 , including a processing unit  21 , a system memory  22 , and a system bus  23  that couples the system memory to the processing unit  21 . The system memory  22  includes read only memory (ROM)  24  and random access memory (RAM)  25 . A basic input/output system  26  (BIOS), containing the basic routines that help to transfer information between elements within the personal computer  20 , such as during start-up, is stored in ROM  24 . The personal computer  20  further includes a hard disk drive  27 , a magnetic disk drive  28 , e.g., to read from or write to a removable disk  29 , and an optical disk drive  30 , e.g., for reading a CD-ROM disk  31  or to read from or write to other optical media. The hard disk drive  27 , magnetic disk drive  28 , and optical disk drive  30  are connected to the system bus  23  by a hard disk drive interface  32 , a magnetic disk drive interface  33 , and an optical drive interface  34 , respectively. The drives and their associated computer-readable media provide nonvolatile storage for the personal computer  20 . Although the description of computer-readable media above refers to a hard disk, a removable magnetic disk and a CD-ROM disk, it should be appreciated by those skilled in the art that other types of media which are readable by a computer, such as magnetic cassettes, flash memory cards, digital video disks, Bernoulli cartridges, and the like, may also be used in the exemplary operating environment. 
     A number of program modules may be stored in the drives and RAM  25 , including an operating system  35 , one or more application programs  36 , the Account Authority Digital Signature (AADS) module  37 , and program data  38 . A user may enter commands and information into the personal computer  20  through a keyboard  40  and pointing device, such as a mouse  42 . Other input devices (not shown) may include a microphone, joystick, game pad, satellite dish, scanner, or the like. These and other input devices are often connected to the processing unit  21  through a serial port interface  46  that is coupled to the system bus, but may be connected by other interfaces, such as a game port or a universal serial bus (USB). A monitor  47  or other type of display device is also connected to the system bus  23  via an interface, such as a video adapter  48 . In addition to the monitor, personal computers typically include other peripheral output devices (not shown), such as speakers or printers. The personal computer  20  may operate in a networked environment using logical connections to one or more remote computers, such as a remote computer  49 . The remote computer  49  may be a server, a router, a peer device or other common network node, and typically includes many or all of the elements described relative to the personal computer  20 , although only a memory storage device  50  has been illustrated in  FIG. 6 . The logical connections depicted in  FIG. 6  include a local area network (LAN)  51  and a wide area network (WAN)  52 . Such networking environments are commonplace in offices, enterprise wide computer networks, intranets and the Internet. 
     When used in a LAN networking environment, the personal computer  20  is connected to the LAN  51  through a network interface  53 . When used in a WAN networking environment, the personal computer  20  typically includes a modem  54  or other means for establishing communications over the WAN  52 , such as the Internet. The modem  54 , which may be internal or external, is connected to the system bus  23  via the serial port interface  46 . In a networked environment, program modules depicted relative to the personal computer  20 , or portions thereof, may be stored in the remote memory storage device. It will be appreciated that the network connections shown are exemplary and other means of establishing a communication&#39;s link between the computers may be used. 
       FIG. 7  is a block diagram of the components of the preferred embodiment of the present invention. This embodiment of the present invention utilizes the paradigm of the digital signatures as described with respect to  FIG. 3  and merges it into business processes utilized today. 
     Prior to sending a message to the receiver, the sender provides the sender&#39;s public key  730  to the receiver  720 . The receiver then stores the sender&#39;s public key  725 , which will be used to validate electronic messages that will be sent to the receiver. In one embodiment, the sender provides the public key to the receiver when the sender initially establishes an account with the receiver. It is preferable that the receiver stores the sender&#39;s public key along with other sender account information such as name, address, PIN, mother&#39;s maiden name, or other security information that is associated with an account. It is also preferable to not send the sender&#39;s public key to the receiver in the same electronic message that the sender desires to have validated. 
     The sender  710  then creates a sender&#39;s message  700  and attaches the digital signature  705 . The digital signature was created by the process described either in  FIG. 3  or by another process as known to those skilled in the art. 
     The sender sends the sender&#39;s message  700  and the sender&#39;s digital signature  705  to the receiver  720  by way of the network  715 . The network  715  can either be a closed network as is used in the debit card system, or it can be an open network such as the Internet. Because the digital signature is applied, if  715  is an open network such as the Internet, there is a low probability that someone monitoring for traffic and trying to “steal” messages and private information will be able decrypt the digital signature of the sender. 
     Note that in this embodiment, the sender is not sending the public key with the message, and the sender is also not using any certification authorities to authorize this message. Also note that because the standard business process supports validation criteria, adding another criteria, such as a public key, requires minimal modification to the business process. 
     The receiver  720  then receives the sender&#39;s message  700  and the sender&#39;s digital signature  705 . The receiver  720  then automatically retrieves the prestored public key associated with the sender&#39;s other account information and validates  727  the sender&#39;s I digital signature using this prestored public key. Because a digital signature is being used, no one tapping into the network  715  will be able to modify the message as it proceeds to the receiver without then invalidating the digital signature. If the message is modified or corrupted in any manner, the message will fail the validation process and the receiver will refuse the request. 
       FIG. 8  is a block diagram depicting an embodiment of the present invention as it is implemented using a financial institution  825 , a merchant  812  and a customer  810 . The present invention applies in situations where security and the sender&#39;s identification is required. One embodiment is a financial institution that uses standard business processes common in the industry today. In this embodiment, the customer  810  generates requests and provides account information  800 , as well as generates a digital signature  805 . The customer sends this information through the network  815  to the merchant  812 . This information can be used under several situations. For example, if a customer is purchasing groceries at a supermarket and has a smart card that contains his or her private key, or when the customer is using his home computer and is trying to purchase a book or other goods over the Internet from a merchant. 
     The merchant  812  then receives the customer&#39;s request and account information  800  and the customer&#39;s digital signature  805 . The merchant then seeks to have the financial institution authorize the transaction. In other words, the merchant wants the financial institution to confirm the identity of the customer  810  and confirm that there are enough funds in the account to make this purchase. In order to have the transaction authorized, the merchant sends this information to the network  820  to the financial institution  825  for validation. It will be noted that the merchant has not received the private or public key from the customer. The merchant has received a digital signature from the customer and that digital signature will only be valid for this specific request from the customer. If the request is modified in any way, the digital signature will become invalid. This is important because of the high incidence of merchant fraud perpetrated by merchants. So, if the merchant cannot modify the customer&#39;s request in any way without having the digital signature becoming invalid, this will provide a significant savings for the financial institutions and ultimately the customer as well. 
     The financial institution  825 , having received the customer&#39;s request and account information  800 , and the customer&#39;s digital signature  805 , then automatically retrieves the public key  830  that has been previously stored and validates  835  the customer&#39;s digital signature using the prestored public key  830 . Depending on the purpose for which the present invention is implemented, the institution may then act on the customer&#39;s request, such as to authorize a transaction involving the customer&#39;s account. 
     When the financial institution is performing an account authorization, any of the methods known to those skilled in the art may be employed while using the present invention. For example, the financial institution may employ a model using an authorization source and a transaction process. Under this model, when used with a credit card transaction, the authorization source interacts with the merchant to receive the customer account information and the transaction request. The transaction processor may be used to interact with the credit card issuing association to approve the transaction. Methods of account approval are many and are considered within the scope of the present invention when the validation of an electronic message is required. 
     The financial institution  825  then validates the account with the digital signature and returns the results of the validation through the network  820  to the merchant  812 . The merchant then accepts or rejects the request by the customer  810 , notifying the customer via the network  815 . The networks  820  or  815  can be open networks such as the Internet, closed networks, or one could be an open network while the other is a closed network. 
     It should be noted that because the digital signature is encrypted, the public key is not being sent (i.e., the public key has been prestored at the institution), and no certification authorities are being used, the concern of fraudulent tapping into the network to retrieve sensitive customer or sender information has been greatly reduced. Further note that the merchant has only been a pass through mechanism to confirm the identity of the customer to the bank and to verify account information. 
       FIG. 9  is a flow chart depicting the steps performed in implementing an embodiment of the present invention. Method  900  begins at the start (step  905 ) and proceeds to step  910  where public key information is stored in a database along with sender identity information about a sender. This may be performed in a manner well known, for example, when someone opens up a checking account and provides identity information, such as mother&#39;s maiden name, social security number or other types of information required by institutions that require a high level of confidence of the sender&#39;s identity. The sender identity information may be anything that the institution desires, such as account information, sender&#39;s name or any other information the institution wishes to use to associate the sender&#39;s public key to the sender. 
     Proceeding to step  920 , the sender encrypts a message using the sender&#39;s private key. This may be performed using the digital signature methodology described with respect to  FIG. 3 , or may be used by other encryption methods known to those skilled in the art. After encrypting the message, the sender proceeds to step  925  where it sends the encrypted message, the original message, and the sender identity information to the institution. This may be performed over an open network, such as the Internet, where the sender is accessing via a computer, or it may be over a closed network where the sender is sending the encrypted message by way of a smart card at a terminal. 
     Proceeding to step  930 , the institution receives the encrypted message, the original message, and sender identity information and automatically searches the database, using the sender identity information, to find the sender&#39;s public key. The public key that is associated with the sender identity information is then retrieved from the database. At step  930 , the institution decrypts the encrypted message using the retrieved public key that was associated with the sender identity information provided in step  910 . 
     Proceeding to step  940 , the institution then validates the decrypted message with the original message sent. In one embodiment, the validation is performed using the digital signature validation paradigm previously described. After performing the validation, method  900  proceeds to step  945  and stops. 
     This validation process provides two purposes: (1) it determines whether the sender is the originator of the message because it is based on validation information provided by the sender to the institution; and (2) it validates the accuracy of the received message by detecting any changes to the message that was sent. 
     The present invention has been described in relation to particular embodiments which are intended in all respects to be illustrative rather than restrictive. Alternative embodiments will become apparent to those skilled in the art to which the present invention pertains without departing from its spirit and scope. Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing description.