Patent Publication Number: US-6910020-B2

Title: Apparatus and method for granting access to network-based services based upon existing bank account information

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention generally relates to network transaction systems, and more specifically, to a network transaction system applicable to the entire range of cyberspace banking services including new account application, account balance summary, transaction summary, fund transfer, and bill payment. The present invention further relates to a network transaction system applicable to other industries having a closed network for mutual communications, such as credit card services. 
   2. Description of the Related Art 
   Home banking systems have been developed as new strategic services in the finance industry, which will allow a customer to electronically access to their individual bank accounts by connecting his/her home terminal to a central computer of the bank. Customers can enjoy various online banking services such as transaction summary review and fund transfer. To receive those services from the present home banking systems, each customer must have his/her bank account opened beforehand through a traditional, or non-electronic, procedure. That is, a customer should visit the bank and sign up for opening a bank account, where he/she will be usually requested to show something to identify that he/she is really who he/she claims to be. This security process is called a user authentication procedure, and the customer has to pass through this gateway every time he/she newly applies for an account of a different bank. 
   Some financial institutions are proposing such online banking systems that will provide more advanced services using open network environment such as Internet. Those proposed systems allow their customers to sign up for opening a bank account without visiting the bank. Instead, customers can use a virtual branch of the bank disposed on their personal computer platforms that are linked to some bank systems providing online services. Such banking systems are called cyberspace banking. 
   Since every service is provided online in such cyberspace banking systems, the user authentication plays an indispensable roll in security management. How to perform the online user authentication is, therefore, of greater importance in recent years. 
   The use of certifying authorities is proposed as a solution to the above problem. According to this idea, a certifying authority established on a network will issue an electronic certificate that vouches for the bearer&#39;s identity. To get an electronic certificate, users must register their personal data to the authority by sending a mail message or visiting its registration office. This requirement, however, is quite troublesome to the users. When compared with conventional methods, the proposed authentication method has no big difference in the initial expense in time and effort for the customers to get a certificate. 
   Also, from the viewpoint of the banks offering home banking services, the presence of certifying authorities will cause an additional burden on them. They might ask the following questions: “Who will take the initiative in operating the certifying authority?” “Does each bank separately establish such a certifying body?” “Or will it be a unified body to be shared by all the financial institutions involved?” Unfortunately, there seems to be no clear answers to those questions. In reality, however, every cyberspace banking system that is experimentally running now assumes the use of certifying authorities and electronic certificates issued from them for user authentication. 
   A virtual branch is defined as a terminal platform which is virtually set up on each user&#39;s personal computer. When this concept is realized, the users will be able to enjoy a wider range of banking services and business transactions than those offered from the present home banking systems. 
   To make this cyberspace banking commercially operational, it is necessary to solve the troublesomeness imposed to the users in getting an electronic certificate and to eliminate the tasks related to certifying authorities that the banks must deal with. Unless users can easily open an account in their desired banks, the new systems will never be accepted by them. 
   SUMMARY OF THE INVENTION 
   Taking the above into consideration, an object of the present invention is to provide a network transaction system which will allow a user to authenticate himself or herself without using certifying authorities and to receive various cyberspace banking services from any banks as long as they are linked via an inter-bank network. 
   To accomplish the above object, according to the present invention, there is provided a network transaction system in which a customer&#39;s terminal station and a plurality of bank systems are interconnected via networks. In such a network banking environment, the customer wishes to newly open a bank account in a first bank system, while having an existing bank account in a second bank system. The first and second bank systems are among the plurality of bank systems on the networks. 
   The network transaction system of the present invention comprises the three structural elements: customer processing means, first bank processing means, and second bank processing means. The customer processing means, which is disposed at the terminal station, applies for a new bank account by supplying the first bank with existing account information descriptive of the existing bank account owned by the customer in the second bank system. The first bank processing means, which is disposed at the first bank system, requests the second bank system to make a confirmation of the existing bank account, while forwarding the existing account information received from the customer processing means to the second bank system over the networks. The second bank processing means, which is disposed at the second bank system, confirms the existing bank account upon request from the first bank processing means and returns a confirmation response message to the first bank processing means to report the result of the confirmation of the existing bank account. The first bank processing means opens the applied new bank account based on the confirmation response message from the second bank system describing the result of the confirmation of the existing bank account. 
   The above and other objects, features and advantages of the present invention will become apparent from the following description when taken in conjunction with the accompanying drawings which illustrate preferred embodiments of the present invention by way of example. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a conceptual view of a network transaction system according to the present invention; 
       FIG. 2  is a block diagram showing a typical configuration of a cyberspace banking system where a network transaction system according to the present invention is implemented; 
       FIG. 3  is a flowchart showing a procedure of opening a new bank account; 
       FIG. 4  is a diagram to explain a flow of encrypted information; 
       FIG. 5  is a diagram showing an example of a terminal screen used by a customer when applying for a new account; 
       FIG. 6  is a diagram showing an example of a status inquiry screen to report the result of the new account application; and 
       FIG. 7  is a block diagram shows another typical configuration of a cyberspace banking system where the network transaction system of the present invention is implemented. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   An embodiment of the present invention will be described below with reference to the accompanying drawings. Referring first to  FIG. 1 , the following description will outline the principle of the present invention. 
     FIG. 1  is a conceptual view of a network transaction system according to the present invention. The network transaction system of the present invention is implemented in a network environment where a plurality of banks  1   a ,  1   b , and so on are interconnected via a conventional inter-bank network  2 . The bank la is offering cyberspace banking services using an open network  3  to communicate with their potential customers. A terminal station  5  of a customer  4  is linked to this bank la via the open network  3 . The customer  4  wishes to have an account in the bank  1   a , and in this sense, the bank la is referred to as a “target bank.” 
   Meanwhile, the customer  4  owns his/her bank account in another bank  1   b  which has been previously opened. Because this bank  1   b  will play an important role in the present invention, cooperating with the target bank la as will be described below, the bank  1   b  is referred to as a “cooperative bank.” 
   Every bank in this system can be uniquely identified with a bank identification code. The “target bank identification code” and “cooperative bank identification code” refer to the codes of the target bank la and cooperative bank  1   b , respectively. 
   The network transaction system of the present invention comprises customer processing means  6 , target bank processing means  7 , and cooperative bank processing means  8 , which are disposed in separate locations. The customer processing means  6  is placed in a personal computer, for example, that serves as the terminal station  5 . The target bank processing means  7  is located in the target bank  1   a , and the cooperative bank processing means  8  is disposed in the cooperative bank  1   b.    
   Sitting at the terminal station  5 , the customer  4  is now attempting to issue an application for an account of the bank  1   a  for the first time. The customer  4  is prompted to enter some personal information necessary for opening a new account, which information is referred to as “account application information.” This account application information includes: name, address, desired password, and so on. The customer  4  enters such information items to the customer processing means  6  of the terminal station  5 . 
   The customer  4  is also requested to enter “existing account information” that describes one of the bank accounts that the customer  4  currently holds. This existing account information actually includes: cooperative bank identification code, account number, password, and the like. Upon receipt of the account application information and existing account information, the customer processing means  6  transmits them all to the target bank  1   a  over the open network  3 . 
   In the bank  1   a , the target bank processing means  7  receives the account application information and existing account information transmitted from the customer processing means  6 . The target bank processing means  7  then forwards the received existing account information to the bank  1   b  where the customer&#39;s bank account resides, thereby requesting the cooperative bank processing means  8  to make a confirmation of the identity of the customer  4 . This authentication request, or actually an account confirmation request, is delivered to the bank  1   b  over the inter-bank network  2 . 
   The cooperative bank processing means  8  in the bank  1   b  receives the existing account information and compares it with the entries of a registered account directory  8   a  stored therein, thereby confirming that the customer&#39;s account is registered as claimed in the existing account information. The result of this account confirmation is sent back to the bank  1   a  via the inter-bank network  2 . 
   The target bank processing means  7  in the bank  1   a  receives this response from the cooperative bank processing means  8 . Based on this response, the target bank processing means  7  decides whether to create or not to create an account for the customer  4 . When the target bank processing means  7  decided to allow opening the customer&#39;s account, it sends “new account acknowledgment information” to the terminal station  5  to notify the customer  4  of acceptance of his/her application. The target bank processing means  7  then creates a new bank account  7   a  in the bank  1   a , using the account application information that was sent from the terminal station  5  when the customer  4  issued the application. 
   In the way described above, the customer  4  can newly open an account of the bank la without visiting a branch office of the bank  1   a , but only by entering necessary information to his/her terminal station  5 . Note here that the bank  1   a  used the customer&#39;s existing account in the different bank  1   b  to authenticate the applicant, or the customer  4 . This method will eliminate the need of special certifying authorities and simplify the account opening procedure. 
   This method originates from the concept that a customer who has a valid account in one of the banks on the network must have once passed a normal user authentication procedure. As long as the validity of his/her bank account can be confirmed, there will be no need to repeat a like procedure each time a new application is issued from the same customer. The bank account used for such authentication purposes is not restricted to one registered in a specific bank, but can be of any banks linked to the target bank la via the inter-bank network  2 . 
   The target bank  1   a , of course, can also play as a cooperative bank if the customer has a valid account in the bank  1   a . In this case, the target bank processing means  7  will make an account confirmation by itself. Besides being applicable to new account applications, the network transaction system of the present invention can be used in general banking transactions such as online inquiry of the account balance summary. Those two cases will be described separately as alternative configurations of the present invention. 
   The following description will present an embodiment of the present invention, in which a cyberspace banking system is constructed on an open network such as Internet. When trying to open a new account in a certain bank, the customer must follow either one of two different procedures depending on whether he/she already has an account in that bank or not. The following description will start with an assumption that the customer currently has no account in the target bank. 
     FIG. 2  is a block diagram showing a typical configuration of a cyberspace banking system according to the present invention. As in  FIG. 1 , the system shown in  FIG. 2  contains three entities; a terminal station  10 , a target bank system  30 , and a cooperative bank system  50 . Via an open network  20  such as Internet, the terminal station  10  at the customer&#39;s site is linked to the target bank system  30  disposed in the bank where the customer wishes to open an account. The target bank system  30  is further linked to the cooperative bank system  50  via a proprietary inter-bank network  40 , in which the customer&#39;s existing bank account is registered. 
   The terminal station  10  comprises an input information processor  11 , a secret/public key generator  12 , an encryption unit  13 , a decryption unit  14 , an output/storage unit  15 , and a log information storage unit  16 . The input information processor  11  handles information entered by the customer through a keyboard and/or other input devices. The secret/public key generator  12  produces a customer secret key and a customer public key for encryption and decryption of communication messages using a public key cryptosystem. The encryption unit  13  encrypts the entered information and sends the encrypted message to the target bank system  30 . The decryption unit  14  receives a response message from the target bank system  30  and decrypts them so that the output/storage unit  15  will display, print out, and/or store the information contained in the message. The log information storage unit  16  stores operation history records of the terminal station  10 . 
   The target bank system  30  comprises a secret/public key generator  31 , a decryption unit  32 , an encryption unit  33 , an account opening decision unit  34 , an account information storage unit  35 , and a log information storage unit  36 . The secret/public key generator  31  produces a target bank secret key and a target bank public key. The decryption unit  32  decrypts a request message from the terminal station  10  and a response message from the cooperative bank system  50 . The encryption unit  33  encrypts a confirmation request message and sends it to the cooperative bank system  50 , as well as encrypting and transmitting a response message to the terminal station  10 . The account opening decision unit  34  decides whether to accept or to reject a customer&#39;s request for new account, based on the information decoded by the decryption unit  32 . The account information storage unit  35  stores information regarding the bank accounts. The log information storage unit  36  records the operation history in the target bank system  30 . 
   The cooperative bank system  50  comprises a secret/public key generator  51 , a decryption unit  52 , an encryption unit  53 , an account information verification unit  54 , an account information storage unit  55 , and a log information storage unit  56 . The secret/public key generator  51  produces a cooperative bank secret key and a cooperative bank public key. The decryption unit  52  decrypts a confirmation request message from the target bank system  30 . The encryption unit  53  encrypts a response message addressed to the target bank system  30 . The account information verification unit  54  confirms the validity of a bank account that the customer claims to own. The account information storage unit  55  stores directory information regarding the registered bank accounts. The log information storage unit  56  stores the operation history in the cooperative bank system  50 . 
   The above components in the terminal station  10 , target bank system  30 , and cooperative bank system  50  will cooperate with each other to perform a secure process to open a new account for the customer. Referring now to  FIG. 3 , the following description will totally present the process of opening a new bank account. 
     FIG. 3  is a flowchart showing the account opening process, which comprises seven steps S 1 -S 7  as follows. 
   [S 1 ] In the terminal station  10 , the input information processor  11  receives some personal information from the customer. More specifically, the customer enters two classes of information as:
     (a) Information required for opening a new bank account, such as his/her name and address, and   (b) Information on his/her existing bank account, including its account number and password.
 
The former information (a) is referred to as “account application information,” while the latter information (b) is referred to as “existing account information” or “user authentication data.” The encryption unit  13  encrypts those two kinds of data to assemble an account application message and sends it to the target bank system  30 .
   

   [S 2 ] In the target bank system  30 , the decryption unit  32  receives the account application message from the terminal station  10  and decodes the message to extract both the account application information and the user authentication data. The encryption unit  33  then creates a confirmation request message from the extracted user authentication data, and sends it to the cooperative bank system  50 . 
   [S 3 ] In the cooperative bank system  50 , the decryption unit  52  receives the confirmation request message from the target bank system  30 . Decoding that message, the decryption unit  52  obtains the user authentication data. The account information verification unit  54  then searches the directory information stored in the account information storage unit  55  to confirm the presence of the customer&#39;s bank account as is described in the user authentication data. The result of this account confirmation is encrypted by the encryption unit  53  and sent back to the target bank system  30  as a confirmation response message. 
   [S 4 ] In the target bank system  30 , the decryption unit  32  decrypts the received confirmation response message to know the result of the account confirmation performed by the cooperative bank system  50 . Based on the confirmation result, the account opening decision unit  34  determines whether to accept or to reject the application for the new bank account. 
   [S 5 ] If the application is acceptable, then the process advances to step S 6 . Otherwise, the process skips the step S 6 . 
   [S 6 ] The requested new account is created according to the account application information previously received from the terminal station  10 , and this new account is registered to the account information storage unit  35 . 
   [S 7 ] Upon inquiry from the customer, the final result of the application is returned to the terminal station  10 . More specifically, the encryption unit  33  encrypts the result status information to create an application response message. This message is transmitted to the terminal station  10  in response to the inquiry from the applicant (i.e., the customer). In the terminal station  10 , the decryption unit  14  decrypts the application response message to extract the result status information. The output/storage unit  15  displays the extracted status information on a terminal screen. 
   Throughout the above-described process, every operation performed by the terminal station  10 , target bank system  30 , and cooperative bank system  50  is recorded in their respective log information storage units  16 ,  36 , and  56 . 
   Referring next to  FIG. 4 , the following description will focus on how the information is exchanged among the terminal station  10 , target bank system  30 , and cooperative bank system  50  and how the security of the information is maintained. 
     FIG. 4  depicts a flow of encrypted information, where the RSA public-key encryption algorithm is widely adopted. In general, public-key cryptosystems use a pair of encryption/decryption keys, namely, a secret key and a public key. One of those keys is used to encrypt messages, which can be decrypted only by using the other key. For example,  FIG. 4  shows that a customer secret key px and a customer public key ox are assigned to a customer X (i.e., the terminal station  10 ). Similarly, a target bank secret key py and a target bank public key oy are assigned to a target bank Y (i.e., the target bank system  30 ), while a cooperative bank secret key pz and a cooperative bank public key oz are assigned to a cooperative bank Z (i.e., the cooperative bank system  50 ). 
   Assume here that the customer X wishes to open a new account in the target bank Y. The customer X enters the following three classes of information to the terminal station  10 .
     a 0 : Name, address, company, target bank identification code, desired password of the new account, etc.   b 0 : Customer public key ox, cooperative bank identification code, etc.   c 0 : Cooperative bank identification code, account number and password of the existing bank account that is owned by the customer X, etc.   

   The first information a 0  is encrypted by using the customer secret key px and then by using the target bank public key oy. The resultant ciphertext data can be expressed as Foy(Fpx(a 0 )), where Foy and Fpx are encryption functions corresponding to the encryption keys oy and px, respectively. Likewise, the second information b 0  is encrypted by using the target bank public key oy, which results in a second ciphertext Foy(b 0 ). The third information c 0  is encrypted by using the customer secret key px and further by using the cooperative bank public key oz, thereby producing a third ciphertext Foz(Fpx(c 0 )). Lastly, the following plaintext d 0  is combined with the above three kinds of ciphertext data.
     d 0 : Code to define the message format, etc.
 
The above encryption process performed in the terminal station  10  will finally yield an account application message  21  which is expressed as
 
[Foy(Fpx(a 0 )), Foy(b 0 ), Foz(Fpx(c 0 )), d 0 ]
 
This account application message  21  is sent to the target bank system  30 .
   

   The target bank system  30  receives the account application message  21  and decrypts the encrypted information contained in the message. This decryption process is expressed as:
 
Γpy(Foy(Fpx(a 0 )))→Fpx(a 0 )
 
Γpy(Foy(b 0 ))→b 0 
 
where the character Γ (gamma) is used to represent a decryption operator such as Γpy for the decryption key py.
 
   The target bank system  30  decrypts again the ciphertext Fpx(a 0 ) by using the customer public key ox that is included in the information b 0  just decrypted above. This second decryption yields the plaintext information a 0  as
 
Γox(Fpx(a 0 ))→a 0 
 
where Γox represents the decryption function corresponding to the decryption key ox.
 
   The third ciphertext Foz(Fpx(c 0 )) in the account application message, which contains the information c 0  in encrypted form, cannot be processed in the target bank system  30  because it is encrypted with the cooperative bank public key oz (i.e., the secret key pz is necessary to decode it). For the time being, the target bank system  30  leaves this Foz(Fpx(c 0 )) as it is. Although it is not shown in  FIG. 4 , the target bank system  30  returns an acknowledgment message including a reception number to the terminal station  10 , thereby indicating the reception of the account application message. 
   The target bank system  30  then composes a confirmation request message  41  addressed to the secret/public key generator  51 . This message contains the following information e 0  and f 0  in addition to the encrypted information Foz(Fpx(c 0 )) received from the terminal station  10 .
     e 0 : Target bank identification code, customer public key ox, and confirmation request number   f 0 : Code to define the message format
 
While the latter information f 0  is sent as plaintext data, the former information e 0  is encrypted two times by using the target bank secret key py and the cooperative bank public key oz, thereby yielding ciphertext data Foz(Fpy(e 0 )). The confirmation request message  41  is thus expressed as follows.
 
[Foz(Fpx(c 0 )), Foz(Fpy(e 0 )), f 0 ]
   

   The cooperative bank system  50  receives this confirmation request message  41  and decodes the encrypted part of the message to extract their contents. More specifically, the cooperative bank system  50  uses the cooperative bank secret key pz for decryption as:
 
Γpz(Foz(Fpx(c 0 )))→Fpx(c 0 )
 
Γpz(Foz(Fpy(e 0 )))→Fpy(e 0 )
 
   The cooperative bank system  50  then decrypts those two ciphertext data Fpx(c 0 ) and Fpy(e 0 ) by using the customer public key ox and target bank public key oy, respectively, and finally obtains the original plaintext information e 0  and c 0 .
 
Γoy(Fpy(e 0 ))→e 0 
 
Γox(Fpx(c 0 ))→c 0 
 
   The decrypted information c 0  contains the cooperative bank identification code, account number and password of the existing bank account that is owned by the customer X. With this information, the cooperative bank system  50  confirms whether or not the account number claimed by the customer X is registered in the account information storage unit  55  and whether or not the claimed password coincides with the registered password. 
   Upon completion of the account confirmation, the cooperative bank system  50  assembles a confirmation response message  42  including the following two sets of information.
     g 0 : Result of the account confirmation, cooperative bank identification code, and confirmation request number   h 0 : Code to define the message format
 
First, the cooperative bank system  50  encrypts the information go by using the cooperative bank secret key pz, and then it attaches the information h 0  without encryption. This results in a confirmation response message  42  assembled as follows.
 
[Fpz(g 0 ), h 0 ]
 
The confirmation response message  42  is transferred to the target bank system  30 .
   

   After that, the cooperative bank system  50  obtains a log file, in which the history of events and operations are recorded, and saves it into the log information storage unit  56 . For security purposes, a password error counter is prepared for every registered account. In the case that a customer provided a correct account number but happened to enter a wrong password by mistake, the above-described process of account confirmation will detect a password error and increment the password error counter for security record. 
   In the target bank system  30 , the confirmation response message  42  is decrypted by using the cooperative bank public key oz. As a result, the information g 0  is obtained as
 
Γoz(Fpz(g 0 ))→g 0 
 
where Γoz represents the decryption function corresponding to the decryption key oz.
 
   Based on the decrypted information g 0 , the target bank system  30  verifies the identity of the sender of the confirmation response message  42 . More specifically, the target bank system  30  compares the bank identification code as part of the decrypted information g 0  with the known identification code of the cooperative bank Z. If the two codes agree with each other, the target bank system  30  understands that the received message is totally valid. 
   Next, the target bank system  30  decides whether to accept or reject the application for a new bank account, based on the result of the account confirmation. The basis of this decision resides in the information g 0  extracted from the confirmation response message  42 . Note that the confirmation request number contained in the confirmation request message  41  and that extracted from the confirmation response message  42  must be the same number. And only when the decrypted information g 0  shows that the cooperative bank system  50  successfully confirmed the validity of the bank account claimed by the customer X, the target bank system  30  will decide to create a new account as requested by the customer X. 
   When opening an account for the customer X, the target bank system  30  creates a registration record concerning the newly opened bank account, which includes the name, address, customer public key ox, password for the new account, and the like. This record is sent to the account information storage unit  35  for registration. 
   Subsequently, the target bank system  30  assembles an application response message  22  which conveys the following information.
     i 0 : Target bank identification code, result status of the application, reception number, etc.   j 0 : Code to define the message format
 
The target bank system  30  encrypts this information i 0  by using the target bank secret key py and customer public key ox, thereby yielding the ciphertext information Fox(Fpy(i 0 )). The target bank system  30  adds the information j 0  as is to the ciphertext information Fox(Fpy(i 0 )) and finally obtains the application response message  22  as follows.
 
[Fox(Fpy(i 0 )), j 0 ]
 
This application response message  22  is sent to the terminal station  10 .
   

   After sending the message, the target bank system  30  obtains a log file in which the history of events and operations are recorded, and saves it into the log information storage unit  36 . The target bank system  30  then opens the new account for the applicant. 
   The terminal station  10  receives the application response message  22  and decrypts the encrypted information contained in the message. More specifically, the encrypted information Fox(Fpy(i 0 )) is decoded by using the customer secret key px as:
 
Γpx(Fox(Fpy(i 0 )))→Fpy(i 0 )
 
Then the information Fpy(i 0 ) is decrypted by using the target bank public key oy as:
 
Γoy(Fpy(i 0 ))→i 0 
 
   Based on this decrypted information i 0 , the terminal station  10  verifies the identity of the sender of the application response message  22 . More specifically, the terminal station  10  compares the bank identification code as part of the decrypted information i 0  with the known identification code of the target bank Y. If the two codes agree with each other, the terminal station  10  recognizes that the received message is totally valid and allows the result information to be displayed on the terminal screen, printed out upon request, and/or stored in the terminal station  10 . The history of events and operations during the above-described process is recorded in a log file. The terminal station  10  saves such a log file into the log information storage unit  16 . 
   Referring next to  FIG. 5 , the following description will present an example of a terminal screen prepared for a customer who wishes to sign up for a new bank account. 
     FIG. 5  illustrates a terminal screen for online account application. When a customer connects the terminal station  10  to the target bank Y to sign up for a new account, the terminal station  10  will first show him/her a service menu screen. The user then selects an item titled “Opening Your New Account” from among the service menu items. In response to this selection, the terminal station  10  will display a submenu for the selected service menu item. The customer selects a submenu item titled “New Account Application,” and then an account application screen  60  of  FIG. 6  will appear on the terminal screen to prompt the customer to fill out an online application form. 
   The account application screen  60  has blank data fields  61 - 66  as part of the application form, where the user is requested to enter two classes of information; one is relevant to his/her new account to be opened and the other is relevant to his/her existing bank account. 
   The data fields that fall into the former category are: an input field  61  for the user&#39;s name and date of birth; field  62  for address and phone number; field  63  for company name and phone number; and field  64  for desired password for the new account. The information entered to those data fields  61 - 64  will be subject to encryption by using the customer secret key and target bank public key before it is transferred to the target bank system  30 . 
   On the other hand, the remaining data fields  65  and  66 , which fall into the latter category, are prepared respectively for account number and password of an existing bank account that is owned by the applicant. The account number must include the bank identification code and branch identification code to allow the account to be fully identified. The information entered to those two fields will be encrypted by using the customer secret key and cooperative bank public key when it is sent to the target bank system  30 . 
   The application screen  60  further comprises an APPLY button  67  and a CANCEL button  68 . When all the data fields  61 - 66  in the application form are completed, the customer will click the APPLY button  67  to initiate a transaction for opening a new account. The CANCEL button  68  is used to cancel the current session of online account application. 
   Assume that the customer has filled out the form in the account application screen  60 . A mouse click on the APPLY button will submit the entered information to the target bank system  30 . Upon receipt of this account application information, the target bank system  30  returns an acknowledgment message including a reception number to notify the terminal station  10  of the reception of the application submitted. The target bank system  30  then sends a request message to the cooperative bank system  50  to verify the identity of the applicant. This request message is, in other words, a user authentication request. If the user authentication performed by the cooperative bank system  50  has lead an affirmative decision for the account application, the target bank system  30  opens the requested account and saves registration data of the new account. Here, the terminal station  10  can make an inquiry about the current status of the application by sending the reception number that is received as part of the acknowledgment message. The target bank system  30  returns the registration data of the account in response to this inquiry. The following description will present an example screen in such a situation. 
     FIG. 6  illustrates a status inquiry screen that will appear in response to a request for opening a new account. Recall that the selection of the service menu item “Opening Your New Account” invokes a corresponding submenu. In addition to the item “New Account Application” explained above, this submenu also includes an item titled “Application Status Inquiry.” The customer selects this submenu item and enters the reception number that he/she received from the target bank system  30  as part of the acknowledgment message corresponding to his/her new account application. Then the terminal station  10  displays an application status screen  70 . 
   This application status screen  70  contains an account name field  71  and an account number field  72 . The account number field  72  shows the number of the newly opened account that is taught by the target bank system  30 . 
   While the above discussion have focused on such a case that a customer applies for an account of a specific bank for the first time, the following description will cover some different cases. More specifically, a customer may apply for another account of the same bank where his/her old account exists. Once the customer gets such a cyberspace bank account, he/she will be able to use various online banking services through the open networks. The following discussion will also clarify how the present invention will provide a customer with secure services. 
     FIG. 7  shows an alternate configuration of a cyberspace banking system where the network transaction system of the present invention is implemented. Because of its similarity to the configuration of  FIG. 2 , like reference numerals are assigned to like elements. 
   In this cyberspace banking system, a terminal station  10  at the customer&#39;s site is connected via an open network  20  to a target bank system  30 . The customer already has an account in the target bank but he/she wishes to open another account in the same bank. 
   The terminal station  10  comprises an input information processor  11 , a secret/public key generator  12 , an encryption unit  13 , a decryption unit  14 , an output/storage unit  15 , and a log information storage unit  16 . The input information processor  11  processes information entered by the customer. The secret/public key generator  12  produces a customer secret key and a customer public key. The encryption unit  13  encrypts the entered information and sends the encrypted message to the target bank system  30 . The decryption unit  14  receives response messages from the target bank system  30  and decrypts them to allow the output/storage unit  15  to display, print out, and/or store the information contained in the messages. The log information storage unit  16  records the operation history of the terminal station  10 . 
   The target bank system  30  comprises a secret/public key generator  31 , a decryption unit  32 , an encryption unit  33 , an account opening decision unit  34 , an account information storage unit  35 , a log information storage unit  36 , an account information verification unit  37 , and an account information storage unit  38 . The secret/public key generator  31  creates a target bank secret key and a target bank public key. The decryption unit  32  decrypts a request message received from the terminal station  10 . The encryption unit  33  encrypts a response message and sends it to the terminal station  10 . The account opening decision unit  34  decides whether to accept or to reject a customer&#39;s request for a new account. The account information storage unit  35  stores information on the registered bank accounts. The log information storage unit  36  records the operation history in the target bank system  30 . The account information verification unit  37  confirms the validity of the bank account that the customer claims to own. The account information storage unit  38  stores information regarding the registered bank accounts. 
   When applying for a new account, the input information processor  11  in the terminal station  10  prompts the customer to enter the following three sets of information.
     a 1 : Name, address, company, target bank identification code, password choice for the new account, account number and password of the existing bank account that is owned by the customer, etc.   b 1 : Customer public key ox   d 1 : Code to define the message format, etc.
 
The encryption unit  13  encrypts the first information a 1  by using the customer secret key px and further by using the target bank public key oy. The resultant first ciphertext is expressed as Foy(Fpx(a 1 )). Likewise, the encryption unit  13  encrypts the second information b 1  by using the target bank public key oy, thus yielding second ciphertext data Foy(b 1 ). Lastly, the third information d 1  is combined with the above two sets of ciphertext data. As a result, an account application message  21  is assembled as
 
[Foy(Fpx(a 1 )), Foy(b 1 ), d 1 ].
 
This account application message  21  is sent to the target bank system  30 .
   

   The target bank system  30  receives the account application message  21 , and the decryption unit  32  decrypts the encrypted information contained in the message by using the target bank secret key py. This decryption process is expressed as
 
Γpy(Foy(Fpx(a 1 )))→Fpx(a 1 ),
 
Γpy(Foy(b 1 ))→b 1 .
 
The decryption unit  32  further decrypts the ciphertext Fpx(a 1 ) by using the customer public key ox as part of the decrypted information b 1 , thereby yielding the plaintext information a 1  as
 
Γox(Fpx(a 1 ))→a 1 .
 
   The decrypted information a 1  contains the account number and password of the existing bank account that is owned by the customer. This information is sent to the account information verification unit  37  for confirmation. The account information verification unit  37  confirms that the account number claimed by the customer is registered in the account information storage unit  38  and that the claimed password coincides with the registered password. The result of this confirmation is reported to the account opening decision unit  34  to decide whether to accept or to reject the application for a new bank account. If it decides to accept the application, the registration data of the new account is saved into the account information storage unit  35 . 
   When the target bank system  30  receives an inquiry about the application status from the customer, the encryption unit  33  assembles an application response message based on the result of the existing account confirmation. The application response message will convey the following information.
     i 1 : Target bank identification code, result status of the application, reception number, etc.   j 1 : Code to define the message format
 
The encryption unit  33  encrypts this information i 1  by using the target bank secret key py and further by using the customer public key ox. The encryption unit  33  adds the information j 1  to the ciphertext information Fox(Fpy(i 1 )) and finally assembles the application response message as
 
[Fox(Fpy(i 1 )), j 1 ].
 
This application response message is sent to the terminal station  10  in reply to the inquiry.
   

   The terminal station  10  receives the application response message, and the decryption unit  14  decrypts the encrypted information contained in the message. More specifically, the encrypted information Fox(Fpy(i 1 )) is decoded by using the customer secret key px as
 
Γpx(Fox(Fpy(i 1 )))→Fpy(i 1 ).
 
Further, the decryption unit  14  decrypts the information Fpy(i 1 ) using the target bank public key oy as
 
Γoy(Fpy(i 1 ))→i 1 .
 
By displaying this decrypted information i 1  on the terminal screen, the output/storage unit  15  reports the current status of the account application to the customer.
 
   The next description will explain how the customer makes transactions with his/her bank account through online banking services. 
   Transactions are initiated by selecting an item “Home Banking” from among those listed in the initial service menu on the screen of the terminal station  10 . Responding to this selection, the input information processor  11  prompts the customer to enter the following information a 2 .
     a 2 : Account number and password of the bank account that is owned by the customer and the kind of service requested   

   The encryption unit  13  encrypts this information a 2  by using the customer secret key px and the target bank public key oy, thereby obtaining first ciphertext data Foy(Fpx(a 2 )). The encryption unit  13  also encrypts the following information b 2  using the target bank public key oy, and yields second ciphertext data Foy(b 2 ).
     b 2 : Customer public key ox
 
Lastly, the following plaintext d 2  is combined with the above two kinds of ciphertext data.
   d 2 : Code to define the message format, etc.
 
The resultant service request message is expressed as
 
[Foy(Fpx(a 2 )), Foy(b 2 ), d 2 ],
 
which service request message is sent to the target bank system  30 .
   

   In the target bank system  30 , the decryption unit  32  decrypts the received service request message. More specifically, the decryption unit  32  first uses the target bank secret key py for decryption as
 
Γpy(Foy(Fpx(a 2 )))→Fpx(a 2 ),
 
Γpy(Foy(b 2 ))→b 2 .
 
Subsequently, the decryption unit  32  decrypts the ciphertext Fpx(a 2 ) by using the customer public key ox as
 
Γox(Fpx(a 2 ))→a 2 .
 
   The decrypted information a 2  contains the account number and password of the existing bank account that is owned by the customer, which information is sent to the account information verification unit  37  for confirmation. The account information verification unit  37  confirms that the account number claimed by the customer is registered in the account information storage unit  38  and that the claimed password coincides with the registered password. The result of this confirmation is reported to a service processor (not shown in  FIG. 7 ) in the target bank system  30 . The service processor evaluates the confirmation result, and if the result was affirmative, the service processor provides the requested service after parsing the contents of the decrypted information a 2 . The available services include account balance summary, transaction history, and fund transfer, and the like. The output of the service processor is sent to the encryption unit  33 . 
   Upon receipt of an inquiry of the current status of service transaction, the encryption unit  33  assembles a response message to be returned to the customer. More specifically, the encryption unit  33  prepares the following information i 2  and j 2 .
     i 2 : Target bank identification code, result status of the service request, reception number, etc.   j 2 : Code to define the message format
 
The encryption unit  33  encrypts the information i 2  by using the target bank secret key py and customer public key ox, thereby yielding the ciphertext information Fox(Fpy(i 2 )). The encryption unit  33  adds the information j 2  as is to the ciphertext Fox(Fpy(i 2 )) and finally obtains a response message expressed as
 
[Fox(Fpy(i 2 )), j 2 ],
 
and this response message is transmitted to the terminal station  10 .
   

   The decryption unit  14  in the terminal station  10  decrypts the encrypted information contained in the received response message. More specifically, the encrypted information Fox(Fpy(i 2 )) is decoded by using the customer secret key px as
 
Γpx(Fox(Fpy(i 2 )))→Fpy(i 2 ),
 
and this ciphertext information Fpy(i 2 ) is further decrypted by using the target bank public key oy as
 
Γoy(Fpy(i 2 ))→i 2 .
 
Based on this decrypted information i 2 , the output/storage unit  15  displays the result of his/her service request.
 
   The above discussion will be summarized as follows. In a cyberspace banking system based on an open computer network, user authentication is a vital process for security. When applying for a new bank account, a customer is required to show that he/she is the exact person who he/she claims to be. The present invention makes this user authentication process much easier, by using the applicant&#39;s existing bank account as a kind of certificate. Inter-bank financial networks makes it possible to verify the validity of a remote account. When the applicant&#39;s remote account was successfully confirmed, it implies that the applicant has once passed the authentication process in that bank. The idea of using the existing inter-bank networks to confirm the identities of customers will allow the authentication process to be greatly simplified and thus enable the customers to fully enjoy the cyberspace banking services of any banks they desire. The present invention also eliminates the need of user registration to certifying authorities, as well as allowing the banks to be free from operations and management pertaining to such certifying authorities. This will be of great benefit to both customers and banks. 
   The foregoing is considered as illustrative only of the principles of the present invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and applications shown and described, and accordingly, all suitable modifications and equivalents may be regarded as falling within the scope of the invention in the appended claims and their equivalents.