JP2009151670A - Data transfer processing system, data transfer processing method, and data transfer processing program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a data transfer processing system, a data transfer processing method and a data transfer processing program capable of efficiently and accurately transferring data with both a common key and a public key. <P>SOLUTION: When storing a request file in a magnetic tape 50, a control part 11 of a user terminal 10 generates a new common key, encrypts the request file using this common key, and records it in the magnetic tape 50. Then, the control part 11 encrypts the common key using a bank public key and records it in the magnetic tape 50. The magnetic tape 50 is carried to a bank. A control part 21 of an input/output device 20 in the bank specifies the generation of the public key recorded in the magnetic tape 50 and acquires a secret key. Then, the control part 21 decodes the common key and decodes the request file using this common key. The control part 21 carries out transaction processing using the request file and further updates the bank public key recorded in the magnetic tape 50. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a data transfer processing system, a data transfer processing method, and a data transfer processing program for transferring data using a recording medium.

  In exchange of data between a company and a bank, a recording medium such as a magnetic tape or a magneto-optical disk may be used. On the other hand, with the enforcement of the Personal Information Protection Law, there is an increasing need for improving data security.

  In order to suppress such information leakage from the recording medium, a technique for suppressing information leakage even when a magnetic tape is stolen by an insider who can know a password has been studied (for example, Patent Document 1). See). The technology described in this document uses a storage system that includes a server, an encryption device, and a storage device, and stores information in the storage device. The server includes means for storing the secret key, means for transmitting the information together with the secret key to the encryption device, and means for transferring the encrypted information received from the encryption device to the storage device. Then, the encryption device encrypts the information transmitted from the server using a secret key, and transmits the encrypted information to the server. The storage device stores the encrypted information transferred from the server.

  Also, a technique for backing up data safely even when a common key cryptosystem is used has been studied. (For example, see Patent Document 2). In the technique described in this document, a file to be backed up is divided into a plurality of blocks, and each block is encrypted using different encryption keys. Each encrypted block is stored and stored in a recording medium such as a magnetic tape.

In addition, data storage devices for improving the confidentiality and security of backup data are also being studied. (For example, see Patent Document 3). In the technique described in this document, when backing up user data from a magnetic disk device to a tape library device in a data center, a backup ID is generated, and an encryption key is requested from the user via a network. Then, the user generates and stores an encryption key / decryption key pair corresponding to the backup ID, and sends the encryption key corresponding to the backup ID to the data center. In this case, the user data is encrypted by the encryption / decryption device. When restoring, the backup ID is sent from the data center to the user, the user sends the decryption key corresponding to the backup ID to the data center, and the user data read from the tape library device by the encryption / decryption device Is restored to the magnetic disk device.
JP 2006-279243 A (first page) JP 2006-260224 A (first page) JP2003-208355A (first page)

  In the exchange of data using a recording medium such as a magnetic tape or a magneto-optical disk, a standard procedure such as SSL (Secure Socket Layer) used in a network has not been established.

Further, in data encryption, a public key cryptosystem or a common key cryptosystem is used as in the above-mentioned patent document. Here, in the encryption of the recording medium, the common key cryptosystem is efficient and easy to use, but there is a problem that key management must be performed for each customer. On the other hand, in the case of the public key cryptosystem, if the amount of data is large, the system load required for encryption or decryption increases, making it practically difficult to use.

  Also, when transferring data using magnetic tape, magneto-optical disk, etc., the network environment is often inadequate, and it is widely used on the network. In many cases, encryption tools cannot be applied. Therefore, a simple and efficient data encryption method is desired even in such an environment.

  In the Internet, since data is distributed on an open network, it is necessary to logically specify the other party. On the other hand, when using a magnetic tape or a magneto-optical disk, the other party is physically specified. Specifically, data is exchanged by delivering a recording medium on the assumption that the other party actually exists. Therefore, it is desirable that the method for transferring data using the recording medium also takes into account such a use environment.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a data transfer processing system, a data transfer processing method, and a data transfer processing program for transferring data efficiently and accurately. There is.

  In order to solve the above problem, the invention described in claim 1 is characterized in that a first public key storage area storing a first public key managed by a server executing processing of a request file and a client terminal manage A second public key storage area in which a second public key is stored, an encrypted common key storage area in which a common key encrypted using the first or second public key is stored, and the common A processing system for transferring data using a recording medium having an encrypted file storage area for storing data encrypted using a key, wherein the client terminal reads the previous recording medium In this case, the means for obtaining the first public key recorded in the first public key storage area, generating a new common key, and encrypting the request file to be provided to the server using the common key Data recording medium Means for recording in an encrypted file storage area, means for encrypting the common key using the first public key obtained via the first public key storage area, and recording the encrypted common key storage area; A gist is provided with means for recording the second public key in the second public key storage area.

  According to a second aspect of the present invention, in the data transfer processing system according to the first aspect, the server records data acquired from the encrypted common key storage area of the recording medium in the first public key storage area. Means for decrypting with the first secret key corresponding to the first public key thus extracted and extracting the common key; decrypting the data obtained from the encrypted file storage area with the extracted common key and requesting The gist is that a means for obtaining a file is provided.

  According to a third aspect of the present invention, in the data transfer processing system according to the second aspect, when the server acquires a result file to be provided to the client terminal corresponding to the request file, a new common key is obtained. And means for recording the data obtained by encrypting the result file using the common key in the encrypted file storage area of the recording medium, the second public key acquired via the second public key storage area The gist is provided with means for encrypting the common key using the key and recording it in the encrypted common key storage area.

  According to a fourth aspect of the present invention, in the data transfer processing system according to the third aspect, the server uses the encrypted common key obtained by encrypting a common key using the second public key as the encrypted common key. In the case of recording in the key storage area, the gist of the present invention is further provided with means for updating the first public key recorded in the first public key storage area.

  According to a fifth aspect of the present invention, in the data exchange processing system according to any one of the first to fourth aspects, the recording medium records an expiration date for recording the expiration dates of the first and second public keys. In summary, the client terminal and the server further include means for encrypting the common key using the first or second public key that has not reached the expiration date.

  The invention according to claim 6 stores a first public key storage area in which a first public key managed by a server that executes processing of a request file is stored, and a second public key managed by a client terminal. A second public key storage area, an encrypted common key storage area in which a common key encrypted using the first or second public key is stored, and data encrypted using the common key A method for performing data transfer processing using a processing system for data transfer using a recording medium having an encrypted file storage area for storing data, wherein the client terminal If read, the step of obtaining the first public key recorded in the first public key storage area, generating a new common key, and encrypting the request file to be provided to the server using the common key Previous data Recording in the encrypted file storage area of the recording medium, encrypting the common key using the first public key acquired via the first public key storage area, and recording the encrypted key in the encrypted common key storage area And performing the step of recording the second public key in the second public key storage area.

  According to a seventh aspect of the present invention, in the data transfer processing method according to the sixth aspect, the server records the data acquired from the encrypted common key storage area of the recording medium in the first public key storage area. Decrypting with the first secret key corresponding to the first public key thus extracted and extracting the common key, decrypting the data obtained from the encrypted file storage area with the extracted common key and requesting The gist is to further execute the step of acquiring the file.

  The invention according to claim 8 is the data exchange processing method according to claim 7, wherein when the server obtains a result file to be provided to the client terminal corresponding to the request file, a new common key is created. And recording the data obtained by encrypting the result file using the common key in the encrypted file storage area of the recording medium, the second public key obtained through the second public key storage area The method further includes the step of encrypting the common key using the key and recording the same in the encrypted common key storage area.

  According to the ninth aspect of the present invention, a first public key storage area in which a first public key managed by a server executing request file processing is stored and a second public key managed by a client terminal are stored. A second public key storage area, an encrypted common key storage area in which a common key encrypted using the first or second public key is stored, and data encrypted using the common key A program for performing data exchange processing using a processing system for performing data transmission / reception using a recording medium having an encrypted file storage area for storing data, wherein the client terminal is connected to a pre-recording medium. When read, the means for obtaining the first public key recorded in the first public key storage area, generating a new common key, and encrypting the request file to be provided to the server using this common key Day Means for recording the encrypted common key in the encrypted file storage area of the recording medium, and encrypting the common key using the first public key acquired via the first public key storage area, and the encrypted common key storage area And a function for recording the second public key in the second public key storage area.

In the tenth aspect of the present invention, a first public key storage area in which a first public key managed by a server executing request file processing is stored and a second public key managed by a client terminal are stored. A second public key storage area, an encrypted common key storage area in which a common key encrypted using the first or second public key is stored, and data encrypted using the common key A program for performing data exchange processing using a processing system for performing data transmission / reception using a recording medium having an encrypted file storage area for storing data, wherein the server is configured to encrypt the recording medium. Means for decrypting the data acquired from the encrypted common key storage area with a first secret key corresponding to the first public key recorded in the first public key storage area, and extracting the common key, the encrypted file From storage The data, and summarized in that function as means for acquiring a request file is decrypted using the common key mentioned above extraction.

  According to an eleventh aspect of the present invention, in the data transfer processing program according to the tenth aspect, when the server obtains a result file to be provided to the client terminal corresponding to the request file, a new common key is obtained. And means for recording the data obtained by encrypting the result file using the common key in the encrypted file storage area of the recording medium, the second public key acquired via the second public key storage area The gist is to further function as a means for encrypting the common key using the key and recording it in the encrypted common key storage area.

(Function)
According to the first, sixth, or ninth aspect of the present invention, the first public key storage area in which the first public key managed by the server that executes the processing of the request file is stored, and the second public key that is managed by the client terminal. A second public key storage area in which the public key is stored, an encrypted common key storage area in which the common key encrypted using the first or second public key is stored, and encryption using the common key A recording medium having an encrypted file storage area for storing the converted data is used. When the client terminal reads the recording medium, the client terminal acquires the first public key recorded in the first public key storage area. Further, a new common key is generated, and data obtained by encrypting the request file to be provided to the server is recorded in the encrypted file storage area of the recording medium using the common key. Further, the common key is encrypted using the first public key acquired through the first public key storage area, and is recorded in the encrypted common key storage area. Then, the second public key is recorded in the second public key storage area. Thereby, it is possible to apply the common key encryption method and the public key encryption method using the recording medium without connecting to the network. Therefore, it is possible to improve security when providing request data to be provided to the server.

  In this case, since the common key is encrypted and stored in the recording medium, the key management burden can be reduced. In particular, even when there is a time lag between request and result return in offline data transfer, there is no need to hold and manage the session key (common key), improving the convenience for the user. it can.

Furthermore, by recording the second public key in the second public key storage area, it is possible to provide a key used when encryption is performed in the server and update the other party.
According to the invention of claim 2, 7 or 10, the server decrypts the data acquired from the encrypted common key storage area of the recording medium with the first secret key corresponding to the first public key. Extract the common key. Then, the request file is acquired by decrypting the data acquired from the encrypted file storage area using the extracted common key. Thereby, the encrypted data generated using the common key cryptosystem and the public key cryptosystem can be decrypted.

  According to the invention of claim 3, 8 or 11, when a result file corresponding to the request file is acquired, a new common key is generated, and data obtained by encrypting the result file using the common key is recorded. Record in the encrypted file storage area of the medium. And a common key is encrypted using the 2nd public key acquired via the 2nd public key storage area, and it records on an encryption common key storage area. As a result, security can be improved even when result data for request data is returned.

According to the invention described in claim 4, when the server records the encrypted common key obtained by encrypting the common key using the second public key in the encrypted common key storage area, the first public The first public key recorded in the key storage area is updated. Thereby, security can be secured using the updated first public key.

  According to the fifth aspect of the present invention, the information processing apparatus further includes an expiration date storage area for recording an expiration date of the first public key. Thereby, the security of the public key can be improved.

  According to the present invention, it is possible to provide a data transmission / reception processing system, a data transmission / reception processing method, and a data transmission / reception processing program capable of efficiently and accurately exchanging both a common key and a public key. In addition, the key that must be managed is its own “public key-private key” set and the other party's “public key”, which reduces the management burden of “common keys” that require strict secret management. Can do.

  Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS. In this embodiment, a data transfer processing system, a data transfer processing method, and a data transfer processing program used when transferring data between a customer and a bank will be described. In the present embodiment, as shown in FIG. 1, data is exchanged between a customer and a bank using a magnetic tape 50 as a recording medium.

  As shown in FIG. 2, a format 500 is set on the magnetic tape 50 in order to exchange data between a customer and a bank. The format 500 includes a header record area 510 and a provision data area 520.

  The header record area 510 includes a ciphertext identification flag storage field, a bank code storage field, and a customer code storage field. The header record area 510 further includes a bank public key storage field, a bank public key expiration date storage field, a customer public key storage field, and a customer public key expiration date storage field. The header record area 510 includes a common key encryption method identifier storage field and an encrypted common key storage field. Here, the bank public key expiration date storage field and the customer public key expiration date storage field function as an expiration date information storage area.

  In the ciphertext identification flag storage field, a flag for specifying whether or not the data stored in the provided data area 520 is encrypted is recorded. When a ciphertext identification flag is recorded in this storage field, it indicates that encrypted data is recorded in the provided data area 520. If the ciphertext identification flag is not recorded, plaintext data is recorded on the magnetic tape 50.

In the bank code / customer code storage field, data relating to an identifier for identifying the bank or customer using the magnetic tape 50 is recorded.
In the bank public key storage field (first public key storage area), the public key (first public key) of the bank using the magnetic tape 50 is recorded.

In the bank public key expiration date storage field, data relating to the expiration date of the bank public key is recorded.
In the customer public key storage field (second public key storage area), the public key (second public key) of the customer who uses the magnetic tape 50 is recorded.

Data related to the expiration date of the customer public key is recorded in the customer public key expiration date storage field.
In the common key encryption method identifier storage field, data relating to an identifier for specifying the encryption method used for encrypting the data recorded in the provided data area 520 is recorded. An example of this common key encryption method is AES (Advanced Encryption Standard).

In the encrypted common key storage field (encrypted common key storage area), data obtained by encrypting the common key used for encrypting the data recorded in the provided data area 520 with the public key of the data recipient side Is recorded.
The provided data area 520 functions as an encrypted file storage area. In the provided data area 520, data provided to the bank or the customer is recorded.

  In this embodiment, as shown in FIG. 1, data is read and written with respect to the magnetic tape 50 using a data transfer processing system including a user terminal 10 of a customer and an input / output device 20 of a financial institution. Do. Further, the input / output device 20 is connected to the host system 30. In this embodiment, the user terminal 10 functions as a client terminal, and the input / output device 20 and the host system 30 function as a server. The host system 30 is a computer system that manages an account opened in a bank. Banking processing is executed by the customer request file acquired from the input / output device 20.

  The user terminal 10 is a computer terminal used by a customer, and includes a magnetic tape device for reading and writing the magnetic tape 50. Further, the user terminal 10 includes a control unit 11. The input / output device 20 is input / output interface means for reading and writing the magnetic tape 50 in a bank. The input / output device 20 communicates with the host system 30.

  The control unit 11 of the user terminal 10 and the control unit 21 of the input / output device 20 perform data encryption processing and decryption processing. The control units (11, 21) have a CPU, RAM, ROM, and the like as control means, and perform processes (decryption process stage, encryption process stage, etc.) described later. By executing a data exchange processing program (encryption processing program or decryption processing program) for this purpose, the control unit (11, 21), as shown in FIG. 3, performs decryption processing means (11a, 21a) and encryption. It functions as processing means (11b, 21b).

  The decryption processing means (11a, 21a) includes medium reading means (111, 211), public key cryptosystem decryption means (112, 212), common key cryptosystem decryption means (113, 213), data output means (114, 214) and key management means (110a, 210a).

  Also, the encryption processing means (11b, 21b) includes data acquisition means (115, 215), common key generation means (116, 216), common key encryption system encryption means (117, 217), public key encryption system encryption. Including a conversion means (118, 218), a medium writing means (119, 219), a key update means (110b, 210b), and a term management means (110c, 210c).

  The key management means (110a, 210a) uses the other party's public key or expiration date read from the header record area 510 of the magnetic tape 50 via the medium reading means (111, 211) to store key data to be described later. The partner side key table (122, 222) of the part (12, 22) is updated.

  Further, the key update means (110b, 210b) indicates the latest generation public key and expiration date recorded in the own key table (121, 221) of the key data storage unit (12, 22) as the header record of the magnetic tape 50. Recording is performed in the area 510 through the medium writing means (119, 219).

The term management means (110c, 210c) confirms the expiration date of the other party's public key and determines whether it can be used.
The medium reading means (111, 211) executes processing for reading various data such as provided data and header records from the magnetic tape 50.

  The public key cryptosystem decrypting means (112, 212) uses the public key recorded in the header record read from the magnetic tape 50 to identify the generation of this public key and to identify the secret key in this generation. Execute. Then, using this secret key, a process for decrypting the encrypted common key is executed.

The common key cryptosystem decrypting means (113, 213) executes a process of decrypting the provided data using the common key.
Data output means (114, 214) outputs the decoded data. In the present embodiment, the data output unit 114 of the user terminal 10 outputs a result file to a data storage unit, a display, or the like. The data output unit 214 of the input / output device 20 outputs the request file to the host system 30.

  The data acquisition means (115, 215) acquires data to be encrypted. In the present embodiment, the data acquisition unit 115 of the user terminal 10 acquires a request file from the data storage unit in the user terminal 10. The data acquisition unit 215 of the input / output device 20 acquires the result file from the host system 30.

  The common key generation means (116, 216) executes processing for generating a common key for data encryption. In this embodiment, a random number of digits used in a predetermined shared key encryption method is used as a common key.

  The common key cryptosystem encryption means (117, 217) executes the provided data encryption processing using the common key generated by the common key generation means (116, 216). Then, the encrypted data is stored in the provided data area 520 of the magnetic tape 50.

The public key cryptosystem encryption means (118, 218) encrypts the common key generated by the common key generation means (116, 216) using the public key acquired via the header record area 510 of the magnetic tape 50. Execute the conversion process. In the present embodiment, the public key cryptosystem encryption unit 118 executes encryption processing using a bank public key, and the public key cryptosystem encryption unit 218 executes encryption processing using a customer public key.
The medium writing means (119, 219) executes processing for writing the encrypted provided data, the encrypted common key, its own public key, etc. on the magnetic tape 50.

  Further, the user terminal 10 and the input / output device 20 each include a key data storage unit (12, 22). A key table used in the public key cryptosystem is registered in the key data storage unit (12, 22).

In the key data storage unit 12 of the customer user terminal 10, as shown in FIG. 4A, a self-side key table 121 and a counterpart side key table 122 are recorded. In the own side key table 121, data relating to a public key, a secret key, and an expiration date is registered for each generation identifier of the customer (here, a customer). Even when a plurality of keys are used in combination, the generation corresponding to the public key and the secret key of this generation can be specified by using the own key table 121. In the other party key table 122, the public key acquired from the other party (here, the bank) and data related to the expiration date are registered. Further, in order to conduct transactions with a plurality of banks, a public key and an expiration date are registered for each bank code in the customer partner key table 122.

  In addition, as shown in FIG. 4B, the key data storage unit 22 of the bank input / output device 20 records a local key table 221 and a counterpart key table 222. In the self-side key table 221, data relating to the public key, the secret key, and the expiration date is registered for each generation identifier of the self (here, bank). Even when a plurality of keys are used in combination, the generation corresponding to the public key and the secret key of this generation can be specified by using the own key table 221. In the counterpart side key table 222, the public key acquired from the counterpart side (here, the customer) and data related to the expiration date are registered. In addition, in the bank's counterpart key table 222, a public key and an expiration date are registered for each customer code in order to conduct transactions with a plurality of customers.

  A processing procedure when data is exchanged between a customer and a bank using the system configured as described above will be described with reference to FIGS. Here, first, a key update process (FIG. 5), an encryption process (FIG. 6), and a decryption process (FIG. 7) executed in common in the user terminal 10 and the input / output device 20 will be described. Then, using these, the data transfer process (FIG. 8) between the customer and the bank will be described.

(Key update process)
First, the key update process will be described with reference to FIG. This process is executed when the magnetic tape 50 is set in the user terminal 10 or the input / output device 20.

  Here, first, the control unit (11, 21) executes a process of acquiring the partner side key information (step S1-1). Specifically, the key management means (110 a, 210 a) of the control unit (11, 21) acquires the other party's public key and public key expiration date from the header record area 510 of the magnetic tape 50.

  Next, a control part (11, 21) performs the confirmation process of an effective period (step S1-2). Specifically, the key management means (110a, 210a) compares the current date with the public key expiration date acquired from the magnetic tape 50, and the public key expiration date has already passed (step S1- In the case of “NO” in 2), the key management means (110a, 210a) ends the key update process. On the other hand, when the current date has not reached the public key expiration date (in the case of “YES” in step S1-2), the control unit (11, 21) executes a verification process for the length of the expiration date ( Step S1-3). Specifically, the key management means (110a, 210a) acquires the expiration date of the public key recorded in the counterpart key table (122, 222) of the key data storage unit (12, 22), and the magnetic tape 50 Compare with the expiration date obtained from.

  When the expiration date of the public key recorded in the counterpart key table (122, 222) is longer (in the case of “NO” in step S1-3), the key management means (110a, 210a) performs key update processing. Exit.

  On the other hand, when the expiration date acquired from the magnetic tape 50 is longer (in the case of “YES” in step S1-3), the control unit (11, 21) executes update processing of the partner key information ( Step S1-4). Specifically, the key management means (110a, 210a) of the control unit (11, 21) updates and records the public key and the expiration date acquired from the magnetic tape 50 in the counterpart key table (122, 222).

(Encryption processing)
Next, the encryption process will be described with reference to FIG. This process is executed when the magnetic tape 50 is set in the user terminal 10 or the input / output device 20 and an information recording instruction is input.

  Here, first, the control unit (11, 21) executes the acquisition process of the expiration date of the other party public key (step S2-1). Specifically, the term management means (110c, 210c) of the control unit 11 acquires the expiration date recorded in the counterpart key table (122, 222) of the key data storage unit (12, 22).

  And a control part (11, 21) performs the confirmation process of an effective period (step S2-2). Specifically, the expiration date management means (110c, 210c) compares the current date with the public key expiration date acquired from the key data storage unit (12, 22), and has already passed the expiration date of the public key. If this is the case (in the case of “NO” in step S2-2), the key management means (110a, 210a) rejects the use (step S2-3). On the other hand, when the current date has not reached the public key expiration date (in the case of “YES” in step S2-2), the control unit (11, 21) executes the process of specifying the encryption target file (step S21). S2-4). Specifically, the control unit (11, 21) acquires a file to be encrypted designated by a user or another system (for example, the host system 30).

  Next, the control unit (11, 21) executes a common key generation process (step S2-5). Specifically, the common key generation means (116, 216) of the control unit (11, 21) records the ciphertext identification flag in the ciphertext identification flag storage field via the medium writing means (119, 219). To do. The common key generation means (116, 216) generates a random number used as a common key used for encrypting the request file.

  Next, the control unit (11, 21) executes encryption processing of the encryption target file using the common key (step S2-6). Specifically, the common key encryption method encryption means (117, 217) of the control unit (11, 21) encrypts the common key encryption method identifier storage field via the medium writing means (119, 219). An identifier (common key encryption method identifier) for specifying the common key encryption method used for encryption is recorded. Next, the common key cryptosystem encryption means (119, 219) encrypts the request file using the common key generated by the common key generation means (116, 216). Then, the common key cryptosystem encryption means (117, 217) sends the encrypted request file (encryption request file) to the provided data area 520 of the magnetic tape 50 via the medium writing means (119, 219). Write to.

  Next, the control unit (11, 21) executes a common key encryption process using the other party's public key (step S2-7). Specifically, the public key cryptosystem encryption means (118, 218) of the control unit (11, 21) is disclosed from the other party key table (122, 222) of the key data storage unit (12, 22). Get the key. Then, the public key cryptosystem encryption means (118, 218) encrypts the common key with the other party's public key. Then, the public key cryptosystem encryption means (118, 218) sends the encrypted common key (encrypted common key) via the medium writing means (119, 219) to the header record area 510 of the magnetic tape 50. Write to.

  Further, the control unit (11, 21) executes a setting process for its own public key (step S2-8). Specifically, the public key cryptosystem encryption unit 118 of the control unit 11 acquires the latest generation public key and expiration date from the own key table (121, 221) of the key data storage unit (12, 22). Then, it is recorded in the header record area 510 via the medium reading means (111, 211).

(Decryption process)
Next, the decoding process will be described with reference to FIG. This process is executed when the magnetic tape 50 is set in the user terminal 10 or the input / output device 20 and an information extraction instruction is input.

  First, a control part (11, 21) performs the specific process of a decoding object file (step S3-1). Specifically, the medium reading means (111, 211) of the control unit (11, 21) acquires the data recorded in the provided data area 520 of the magnetic tape 50.

  Next, a control part (11, 21) performs the acquisition process of an own side public key (step S3-2). Specifically, the public key cryptosystem decrypting means (112, 212) of the control unit (11, 21) is publicly disclosed from the header record area 510 of the magnetic tape 50 via the medium reading means (111, 211). Get the key.

  Next, the control unit (11, 21) executes a secret key identification process (step S3-3). Specifically, the public key cryptosystem decrypting means (112, 212) of the control unit (11, 21) uses the key data storage unit (12, 22) to obtain the public key based on the acquired bank public key. The generation is specified, and the private key corresponding to this public key is acquired from the own key table (121, 221).

  Next, the control units (11, 21) execute a common key decryption process (step S3-4). Specifically, the public key cryptosystem decrypting means (112, 212) of the control unit (11, 21) acquires the encrypted common key from the header record area 510 via the medium reading means (111, 211). . The public key cryptosystem decrypting means (112, 212) decrypts the encrypted common key by using the secret key acquired from the key data storage unit (12, 22).

  Next, a control part (11, 21) performs the decoding process of an encryption file using a common key (step S3-5). Specifically, the common key encryption method decryption means (113, 213) of the control unit (11, 21) is recorded in the common key encryption method identifier storage field via the medium reading means (111, 211). Extracts the key encryption identifier. Then, the common key encryption method decryption means (113, 213) uses the decrypted common key to decrypt the data recorded in the provided data area 520 in accordance with the common key encryption method.

  And a control part (11,21) performs the output process of the decoded file (step S3-6). Specifically, the data output means (114, 214) of the control unit (11, 21) outputs the decrypted file.

(Data exchange between customer and bank)
Next, data exchange processing between the customer and the bank will be described with reference to FIG.
[Initialization of magnetic tape 50]
First, in order to perform initialization processing of the magnetic tape 50, a customer obtains a magnetic tape 50 (empty tape) used when data is exchanged with a bank. Then, bring this blank tape to the bank store and provide it to the bank staff. The clerk sets the magnetic tape 50 in the input / output device 20.

  In this case, the control unit 21 of the input / output device 20 executes a bank public key setting process (step S4-1). Specifically, when the medium reading unit 211 of the control unit 21 detects a blank tape, a format process for setting the header record area 510 and the provided data area 520 is performed. Then, the bank public key and the expiration date are set in the bank code storage field, the bank public key storage field, and the bank public key expiration date storage field of the header record area 510. And the bank employee returns this magnetic tape 50 to the customer.

[Request file recording process]
Next, a process for recording a request file for the bank on the magnetic tape 50 will be described. Then, the customer sets the magnetic tape 50 in the magnetic tape device of the user terminal 10.

  In this case, the control unit 11 of the user terminal 10 performs a key update process (step S4-2). Here, the key management unit 110 a of the control unit 11 acquires the bank code, the bank public key, and the bank public key expiration date from the header record area 510 of the magnetic tape 50 via the medium reading unit 111. If the expiration date has not yet arrived and is the longest, the key management unit 110a updates the counterpart key table 122 of the key data storage unit 12 using the bank code, the bank public key, and the bank public key expiration date. To do.

  Next, the control unit 11 of the user terminal 10 executes a request file encryption process (step S4-3). Here, the user (customer) designates a request file to be provided to the bank, and inputs an instruction for saving to the magnetic tape 50 to the user terminal 10. In this case, the control unit 11 specifies the designated request file in the data storage unit in the user terminal 10. Further, the customer code is recorded in the header record area 510 of the magnetic tape 50 via the medium writing means 119.

  Further, when the user terminal 10 instructs the user terminal 10 to encrypt the request file, the time limit management unit 110c of the control unit 11 confirms the expiration date of the bank public key, and the common key generation unit 116 Execute the generation process. Then, the common key generation unit 116 records the ciphertext identification flag in the ciphertext identification flag storage field via the medium writing unit 119. Then, the common key generating unit 116 generates a random number used as a common key used for encrypting the request file.

  Next, the common key encryption method encryption unit 117 of the control unit 11 uses the medium writing unit 119 to specify the common key encryption method used for encryption in the common key encryption method identifier storage field ( (Common Key Cryptographic Identifier) is recorded.

  Next, the common key encryption method encryption unit 117 encrypts the request file using the common key generated by the common key generation unit 116. Then, the common key encryption method encryption unit 117 writes the encrypted request file (encryption request file) in the provided data area 520 of the magnetic tape 50 via the medium writing unit 119.

  Next, the public key cryptosystem encryption unit 118 of the control unit 11 acquires the bank public key from the counterpart key table 122 of the key data storage unit 12. Then, the public key cryptosystem encryption unit 118 encrypts the common key with the bank public key. Then, the public key cryptosystem encryption unit 118 writes the encrypted common key (encrypted common key) in the header record area 510 of the magnetic tape 50 via the medium writing unit 119.

  Further, the key update unit 110 b of the control unit 11 acquires the public key from the own key table 121 of the key data storage unit 12 and records it in the header record area 510 as the customer public key via the medium reading unit 111.

Then, the customer stores this magnetic tape 50 in a transport box and locks it. The customer brings the shipping box storing the magnetic tape 50 to the bank store.
[Request file execution processing]
Next, request file execution processing will be described. Banks manage keys for locking and unlocking shipping boxes for each customer.

  Then, the bank employee who received the shipping box from the customer obtains a key for unlocking the shipping box of the customer, and unlocks the shipping box. Then, the magnetic tape 50 is taken out from the transport box and set in the input / output device 20.

  In this case, the control unit 21 of the input / output device 20 performs a key update process (step S4-4). Here, the key management unit 210 a of the control unit 21 acquires the customer code, the customer public key, and the customer public key expiration date from the header record area 510 of the magnetic tape 50 via the medium reading unit 211. When the expiration date has not yet arrived and is the longest, the key management unit 210a updates the counterpart key table 222 of the key data storage unit 22 using the customer code, the customer public key, and the customer public key expiration date. To do.

  Next, the control unit 21 of the input / output device 20 executes a request file decryption process (step S4-5). Here, the public key cryptosystem decryption means 212 of the control unit 21 acquires the bank public key from the header record area 510 of the magnetic tape 50 via the medium reading means 211. The public key cryptosystem decrypting means 212 identifies the generation of the public key using the key data storage unit 22 based on the acquired bank public key. Then, the bank secret key corresponding to the bank public key is acquired from the own key table 221 of the key data storage unit 22.

  Next, the public key cryptosystem decrypting unit 212 of the control unit 21 acquires the encrypted common key from the header record area 510 via the medium reading unit 211. Then, the public key cryptosystem decryption means 212 decrypts the encrypted common key using the bank secret key acquired from the key data storage unit 22.

  Next, the common key encryption method decryption unit 213 of the control unit 21 extracts the common key encryption method identifier recorded in the common key encryption method identifier storage field via the medium reading unit 211. Then, the common key cryptosystem decrypting means 213 uses the decrypted common key to decrypt the data recorded in the provided data area 520 according to this common key cryptosystem.

  And the control part 21 of the input / output device 20 performs transaction processing (step S4-6). Specifically, the data output unit 214 of the control unit 21 supplies the decrypted request file to the host system 30. In this case, the host system 30 executes transaction processing based on the request file. Then, the host system 30 returns a result file for this transaction to the input / output device 20.

  In this case, the control unit 21 of the input / output device 20 executes a result file encryption process (step S4-7). Here, the host system 30 designates a result file to be provided to the customer. Further, the bank code is recorded in the header record area 510 of the magnetic tape 50 via the medium writing means 119. Further, the expiration date management unit 210c of the control unit 21 confirms the expiration date of the customer public key, and the common key generation unit 216 of the control unit 21 generates a random number used as the common key.

  Next, the common key encryption unit 217 of the control unit 21 uses the common key generated by the common key generation unit 216 in accordance with the common key encryption method recorded in the common key encryption method identifier storage field. Encrypt the file. Then, the common key cryptosystem encryption unit 217 writes the encrypted result file (encryption result file) in the provided data area 520 of the magnetic tape 50 via the medium writing unit 219.

  Next, the public key cryptosystem encryption unit 218 of the control unit 21 acquires the customer public key from the header record area 510 of the magnetic tape 50 via the medium reading unit 211. Next, the public key cryptosystem encryption unit 218 encrypts the common key with the customer public key. Then, the public key cryptosystem encryption unit 218 writes the encrypted common key (encrypted common key) in the header record area 510 of the magnetic tape 50 via the medium writing unit 219.

Next, specifically, the key updating unit 210b of the control unit 21 acquires the public key from the own key table 221 of the key data storage unit 22, and uses the medium reading unit 211 as a bank public key as a header record. Record in area 510.
Next, the bank clerk stores the magnetic tape 50 in the shipping box and locks it using the customer's key. The bank employee then returns the shipping box storing the magnetic tape 50 to the customer.

[Result file check processing]
Next, the result file confirmation process will be described. The customer who receives the shipping box from the bank uses his key to unlock the shipping box. Then, the magnetic tape 50 is taken out from the transport box, and the magnetic tape 50 is set in the magnetic tape device of the user terminal 10.

In this case, first, the control unit 11 of the user terminal 10 executes a key update process (step S4-8). This process is performed in the same manner as the process of step S4-2.
Next, the control unit 11 of the user terminal 10 executes a result file decryption process (step S4-9). Specifically, the public key cryptosystem decrypting unit 112 of the control unit 11 acquires the encrypted common key from the header record area 510 via the medium reading unit 211. Then, the public key cryptosystem decrypting means 112 decrypts the encrypted common key using the customer private key acquired from the key data storage unit 12.

Next, the common key cryptosystem decryption unit 113 of the control unit 11 decrypts the data recorded in the provided data area 520 using the decrypted common key.
Next, the data output means 114 of the control unit 11 accepts the designation of the output destination by the customer. In this embodiment, a data storage device or a display can be specified as an output destination. Then, the data output unit 114 supplies the decrypted result file to a designated output destination (for example, a display). Then, the customer confirms the result for the request to the bank.

According to this embodiment, the following effects can be obtained.
In the present embodiment, the request file and the result file recorded on the magnetic tape 50 are encrypted using a common key. Thereby, information leakage from the magnetic tape 50 can be suppressed.

  In the present embodiment, the header record area 510 of the magnetic tape 50 includes a ciphertext identification flag storage field, a customer code storage field, a bank public key storage field, a customer public key storage field, a common key encryption method identifier storage field, An encrypted common key storage field is included. Using the public key recorded on the magnetic tape 50, the corresponding secret key can be specified, and the encrypted common key can be decrypted using this secret key. Therefore, even when the public key cryptosystem and the common key cryptosystem are used in combination, the encrypted data can be decrypted using the data recorded on the magnetic tape 50 without connecting to a network or the like.

  In particular, even when a common key is used as a one-time password (session key), it can be obtained from the magnetic tape 50 while ensuring security. Therefore, even when there is a time lag between request and result return in offline data transaction, it is not necessary to hold the magnetic tape 50 for decryption, and the key management burden can be reduced.

In this embodiment, since the other party is authenticated using an entity such as a customer or a bank store, it is not necessary to use an electronic certificate or the like in the public key cryptosystem.
-In this embodiment, the control part (11, 21) of the user terminal 10 and the input / output device 20 performs the setting process of own side public key (step S2-8). When the expiration date acquired from the magnetic tape 50 is longer (in the case of “YES” in Step S1-3), the control unit (11, 21) executes the update process of the partner key information (Step S1). -4). Thereby, the public key used by the other party can be provided via the magnetic tape 50. Then, the public key can be updated.

  In the present embodiment, the recording medium further includes an encryption method identification information storage area in which an encryption identifier for identifying an encryption method using a common key is recorded. Then, in the encryption process, the common key encryption method encryption means (117, 217) uses the medium writing means (119, 219) to specify an encryption method identifier for specifying the encryption method used for encryption. Write to the common key encryption method identifier storage field. In the composite processing, the common key encryption method decryption means (113, 213) of the control unit (11, 21) passes through the medium reading means (111, 211) and the common key recorded in the common key encryption method identifier storage field. Extract cryptographic method identifier. Then, the common key encryption method decryption means (113, 213) uses the decrypted common key to decrypt the data recorded in the provided data area 520 in accordance with the common key encryption method. As a result, various encryption methods can be used.

In addition, you may change each said embodiment as follows.
In the above embodiment, the magnetic tape 50 is used as the recording medium. However, the present invention is not limited to this, and a rewritable magneto-optical disk or the like can also be used.

  ○ In the above embodiment, data transmission / reception between a customer and a bank has been described. However, the present invention is not limited to this. Data backup between individuals and companies, and system backup data for preventing information leakage It is also possible to apply to the exchange of information.

  In the above embodiment, when the magnetic tape 50 is set in the user terminal 10 or the input / output device 20 and an information recording instruction is input, the encryption process is executed. Alternatively, when encryption is not required as in the result file, it is possible to exchange data in plain text and to operate by mixing plain text and cipher text. Specifically, when the encryption identification flag is deleted according to a user instruction, the control unit 21 of the input / output device 20 records the result file on the magnetic tape 50 in plain text.

  In the above embodiment, when the common key encryption process is executed using the other party's public key, the public key cryptosystem encryption means (118, 218) of the control unit (11, 21) is the key data storage unit. The other party public key is acquired from the other party key table (122, 222) of (12, 22). Then, the public key cryptosystem encryption means (118, 218) encrypts the common key with the other party's public key. Alternatively, the public key cryptosystem encryption means (118, 218) can be configured to perform encryption using the public key recorded in the header record area 510. In this case, the public key cryptosystem encryption means (118, 218) confirms the expiration date of the public key recorded in the expiration date storage field, and performs encryption only when the expiration date has not been reached. As a result, it is only necessary to manage their own public key and private key in the key data storage unit (12, 22), and the management burden of the other party's public key can be reduced.

  In the above embodiment, in the encryption process, the control unit (11, 21) executes the setting process of its own public key (step S2-8). In addition to this, it is possible to configure the control unit (11, 21) to execute the setting process of the local public key even after the decryption process is completed. Thereby, even when the encryption process is not performed, the latest public key can be held on the magnetic tape 50.

The system schematic of embodiment of this invention. Explanatory drawing of the data recorded on the magnetic tape. Explanatory drawing of the functional block of a user terminal and an input / output device. It is the data recorded on the key data storage part, Comprising: (a) is a key data storage part of a user terminal, (b) is explanatory drawing of the data recorded on the key data storage part of an input / output device. Explanatory drawing of the process sequence of this embodiment. Explanatory drawing of the process sequence of this embodiment. Explanatory drawing of the process sequence of this embodiment. Explanatory drawing of the process sequence of this embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... User terminal, 11 ... Control part, 20 ... Input / output device, 21 ... Control part, 11a, 21a ... Decryption processing means, 11b, 21b ... Encryption processing means, 110a, 210a ... Key management means, 110b, 210b ... Key update means, 110c, 210c ... time limit management means, 111, 211 ... medium reading means, 112, 212 ... public key encryption method decryption means, 113, 213 ... common key encryption method decryption means, 114, 214 ... data output means, 115, 215 ... data acquisition means, 116, 216 ... common key generation means, 117, 217 ... common key encryption system encryption means, 118, 218 ... public key encryption system encryption means, 119, 219 ... medium writing means.

Claims (11)

A first public key storage area for storing a first public key managed by a server that executes processing of a request file;
A second public key storage area for storing a second public key managed by the client terminal;
An encrypted common key storage area in which a common key encrypted using the first or second public key is stored;
A processing system for transferring data using a recording medium including an encrypted file storage area for storing data encrypted using the common key,
The client terminal is
Means for obtaining a first public key recorded in the first public key storage area when the pre-recording medium is read;
Means for generating a new common key and recording data obtained by encrypting the request file provided to the server using the common key in an encrypted file storage area of the recording medium;
Means for encrypting the common key using the first public key acquired via the first public key storage area and recording the encrypted common key in the encrypted common key storage area;
A data exchange processing system comprising means for recording the second public key in the second public key storage area. The server is
Means for decrypting data acquired from the encrypted common key storage area of the recording medium with a first secret key corresponding to the first public key recorded in the first public key storage area and extracting the common key ,
The data transfer processing system according to claim 1, further comprising means for decrypting data acquired from the encrypted file storage area using the extracted common key and acquiring a request file. The server is
In response to the request file, when a result file to be provided to the client terminal is acquired, a new common key is generated, and data obtained by encrypting the result file using the common key is encrypted on the recording medium. Means for recording in the file storage area,
3. A means for encrypting the common key using a second public key acquired via the second public key storage area and recording the encrypted common key storage area in the encrypted common key storage area. The data transfer processing system described in 1.   When the server records an encrypted common key obtained by encrypting a common key using the second public key in the encrypted common key storage area, it is recorded in the first public key storage area. 4. The data exchange processing system according to claim 3, further comprising means for updating the first public key. The recording medium further includes an expiration date information storage area for recording an expiration date of the first and second public keys,
The client terminal and server further comprise means for encrypting a common key using the first or second public key that has not reached its expiration date. The data transfer processing system described in 1. A first public key storage area for storing a first public key managed by a server that executes processing of a request file;
A second public key storage area for storing a second public key managed by the client terminal;
An encrypted common key storage area in which a common key encrypted using the first or second public key is stored;
This is a method of performing data transfer processing using a processing system that transfers data using a recording medium having an encrypted file storage area for storing data encrypted using the common key. And
The client terminal is
Obtaining a first public key recorded in the first public key storage area when the pre-recording medium is read;
Generating a new common key and recording the encrypted data of the request file to be provided to the server in the encrypted file storage area of the recording medium using the common key;
Encrypting the common key using the first public key obtained via the first public key storage area and recording the encrypted common key storage area;
A data transfer processing method, comprising: recording the second public key in the second public key storage area. The server is
Decrypting the data acquired from the encrypted common key storage area of the recording medium with the first secret key corresponding to the first public key recorded in the first public key storage area, and extracting the common key ,
The data transfer processing method according to claim 6, further comprising the step of decrypting the data acquired from the encrypted file storage area using the extracted common key to acquire a request file. The server is
In response to the request file, when a result file to be provided to the client terminal is acquired, a new common key is generated, and data obtained by encrypting the result file using the common key is encrypted on the recording medium. Recording in the file storage area,
The step of encrypting the common key using the second public key acquired via the second public key storage area and recording the encrypted common key in the encrypted common key storage area is further performed. 8. The data transfer processing method according to 7. A first public key storage area for storing a first public key managed by a server that executes processing of a request file;
A second public key storage area for storing a second public key managed by the client terminal;
An encrypted common key storage area in which a common key encrypted using the first or second public key is stored;
A program for performing data transmission / reception processing using a processing system for performing data transmission / reception using a recording medium having an encrypted file storage area for storing data encrypted using the common key. And
The client terminal is
Means for obtaining a first public key recorded in the first public key storage area when the pre-recording medium is read;
Means for generating a new common key and recording data obtained by encrypting the request file provided to the server using the common key in an encrypted file storage area of the recording medium;
Means for encrypting the common key using the first public key acquired via the first public key storage area and recording the encrypted common key in the encrypted common key storage area;
A data transmission / reception processing program that causes the second public key to function as means for recording in the second public key storage area. A first public key storage area for storing a first public key managed by a server that executes processing of a request file;
A second public key storage area for storing a second public key managed by the client terminal;
An encrypted common key storage area in which a common key encrypted using the first or second public key is stored;
A program for performing data transmission / reception processing using a processing system for performing data transmission / reception using a recording medium having an encrypted file storage area for storing data encrypted using the common key. And
The server,
Means for decrypting data acquired from the encrypted common key storage area of the recording medium with a first secret key corresponding to the first public key recorded in the first public key storage area and extracting the common key ,
A data transmission / reception processing program for causing data acquired from the encrypted file storage area to function as means for acquiring a request file by decrypting the data using the extracted common key. The server,
In response to the request file, when a result file to be provided to the client terminal is acquired, a new common key is generated, and data obtained by encrypting the result file using the common key is encrypted on the recording medium. Means for recording in the file storage area,
The function further comprises means for encrypting the common key using the second public key acquired via the second public key storage area and recording the encrypted common key storage area in the encrypted common key storage area. 10. The data transfer processing program according to 10.

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