JP4385259B2 - Business execution system and method, business execution computer and program - Google Patents

Description

  The present invention relates to a business execution system in which a business execution computer that receives a business processing request from an operation terminal executes business processing.

  In recent years, computers have been used in various businesses, and business execution systems for performing various businesses have been used. In such a business execution system, business is executed by processing specified information by business application software (hereinafter simply referred to as business application or business AP) for performing a specific business. With the spread of communication networks such as the Internet, there are cases where various operation terminals that instruct the execution of business and the business execution computer that executes the business are installed in separate locations (for example, Patent Documents). 1).

  By using such a business execution system, it is possible to make a business process request from the operation terminal from a location different from the location where the business execution computer is installed. However, even if a failure occurs in the business execution computer or a processing request exceeding the processing capacity is made, the operation terminal that requests the business processing cannot recognize the occurrence of the failure, so the business execution In some cases, the business processing request requested to the computer is not processed.

  In order to prevent such an adverse effect, when a failure occurs in a business execution computer in which business execution computers are multiplexed, business processing may be performed by another business execution computer. However, when business execution computers that perform business processing are multiplexed, if a failure occurs in a certain business execution computer, it becomes necessary to transfer information to be processed between the business execution computers. . If the information processed by the business application is confidential information that is not permitted to be leaked to a third party, the security of the confidential information is reduced if the confidential information is transferred between a plurality of business execution computers. It cannot be secured.

In addition, when a business whose execution time is not fixed, such as a business that is executed after a certain business is completed, it is impossible to send information to be processed in accordance with the timing when the business is executed. Therefore, the business execution computer needs to store information to be processed. Therefore, simply multiplexing business execution computers increases the possibility of leakage of confidential information to be processed, and cannot secure safety.
JP-A-10-334160

  In the above-described conventional business execution system, there is a problem that the secret information processed by the business application program is likely to be leaked when the business execution computers are multiplexed.

  An object of the present invention is to provide a business execution method and a business execution system that prevent leakage of confidential information processed by a business application program and improve security even when business execution computers are multiplexed. That is.

In order to achieve the above object, the business execution system of the present invention provides:
A business execution system in which a business execution computer that receives a business processing request from an operation terminal executes business processing,
When the decryption key is received from the operation terminal, the identification code for specifying the decryption key is stored in association with the identification key, the identification code is transmitted to the operation terminal, and a decryption key acquisition request from the business execution computer is transmitted. Upon receipt, a decryption key management computer that searches for a decryption key corresponding to the identification code included in the decryption key acquisition request and transmits the decryption key acquisition request to the business execution computer,
Encrypts secret information to be processed with an encryption key, sends a decryption key for decrypting the encrypted secret information to the decryption key management computer, and requests the business execution computer for the business process An operation terminal for transmitting a file group including a business application program, encrypted secret information, and an identification code received from the decryption key management computer to the business execution computer;
When it is determined that the business process cannot be executed when receiving the file group from the operation terminal and performing the business process, the received file group is transferred to the spare business execution computer, and the business process is executed. When it is determined that the decryption key can be received, a decryption key acquisition request is made by transmitting an identification code included in the file group received from the operation terminal to the decryption key management computer, and the decryption key from the decryption key management computer is obtained. When received, the business execution computer that decrypts the secret information included in the file group with the decryption key and processes the decrypted secret information based on the business application program,
When a file group is transferred from the business execution computer, a decryption key acquisition request is made by transmitting an identification code included in the transferred file group to the decryption key management computer, and the decryption key management computer Upon receiving the decryption key from, it decrypts the secret information contained in the file group by the decoding key, the secret information which is decoded and a spare business executing computer processing based on the business application program ,
The operation terminal, when transmitting a decryption key to the decryption key management computer, transmits an arbitrarily selected passcode,
The decryption key management computer encrypts the passcode received from the operation terminal as encryption information, adds a character string of a unique value to the passcode as the identification code, and from the business execution computer When the decryption key acquisition request is received, the decryption key is decrypted using the passcode extracted from the identification code included in the decryption key acquisition request .

  In the present invention, a spare job execution computer is provided separately from the job execution computer, and if it is determined that the job execution computer cannot execute the job process, the file group from the operation terminal is reserved for job execution. It is transferred to a computer for business processing. The file group transmitted from the operation terminal to the business execution computer includes the encrypted secret information and an identification code for specifying the decryption key for decrypting the encrypted secret information. The identification code and the decryption key are stored and managed in association with the decryption key management computer. Therefore, if a malicious user tries to obtain confidential information illegally, both the business execution computer and the key management computer must be invaded, and the possibility of leakage of confidential information can be reduced.

  Also, until the business process is performed, the confidential information is encrypted and stored only in the business execution computer. Therefore, it is possible to prevent leakage of confidential information due to multiplexing of the business execution computers. Security safety can be ensured.

Further, when the business execution computer and the spare business execution computer transmit a decryption key acquisition request to the decryption key management computer, the disclosure is set for each of the business execution computers. Send the decryption key management computer with the key attached,
When the decryption key management computer transmits a decryption key to each business execution computer, the decryption key management computer encrypts the decryption key with the public key attached to the decryption key acquisition request and transmits the decryption key to the business execution computer.
Upon receiving the encrypted decryption key from the decryption key management computer, each of the business execution computers decrypts the encrypted decryption key using a secret key corresponding to the public key and obtains the decryption key You may make it acquire.

  As described above, according to the present invention, the secret information processed by the business application program is encrypted and stored in the business execution computer, and the decryption key for decrypting the encrypted secret information is managed by the decryption key. When the business execution computer is multiplexed, the decryption key is obtained from the decryption key management computer and the secret information is decrypted when the business processing is actually performed. However, it is possible to obtain an effect that security can be improved while suppressing the possibility of leakage of secret information.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing the configuration of a business execution system according to an embodiment of the present invention. As shown in FIG. 1, the business execution system according to the present embodiment includes two business execution computers 10 and 11, a decryption key management computer 20, and an operation terminal 30.

  Here, in order to simplify the description, a case where business execution computers that perform business processing are multiplexed by the two business execution computers 10 and 11 will be described. The business execution computer 10 is an active device, and the business execution computer 11 functions as a standby device.

  The business execution computer 10 is a computer on which business applications are executed. The business execution computer 10 is connected to the decryption key management computer 20 and the operation terminal 30 via a network and has a function of exchanging information with each other.

  The decryption key management computer 20 stores a decryption key that decrypts secret information used in the business executed by the business execution computer 10 and makes it usable. The decryption key management computer 20 is connected to the business execution computer 10 and the operation terminal 30 via a network and has a function of exchanging information with each other.

  The operation terminal 30 is connected to the decryption key management computer 20 and the business execution computer 10 via a network and has a function of exchanging information with each other. Various operation instructions are given to the business execution computer 10 and the decryption key management computer 20. Has a function of transmitting and obtaining the result. It is assumed that the business execution computer 10 can perform business execution instructions, transmit information necessary for business, and acquire execution results. In addition, it is assumed that the decryption key management computer 20 can register and delete key information for decrypting the encrypted secret information and obtain the processing results thereof.

  Next, the operation of the business execution system of this embodiment will be described in detail with reference to FIGS.

  First, the operation when no failure occurs in the business execution computer 10 will be described with reference to the sequence chart of FIG. Therefore, here, the business execution computer 11 is not directly related to the operation for performing the business processing.

  First, as shown in FIG. 3, the operator 40 who operates the business uses the encryption key 110 for encrypting information from the key issuing organization 50 and the encryption using the encryption key 110 at the operation terminal 30. The decryption key 120 for decrypting the received information is acquired. Next, the operator 40 uses the operation terminal 30 to encrypt the secret information 130 to be processed using the obtained encryption key 110 (step 501).

  Next, as shown in FIG. 4, the operation terminal 30 transmits the decryption key 120 obtained from the key issuing organization 50 together with the passcode 140 to the decryption key management computer 20 based on the operation of the operator 40 ( Step 502). This passcode 140 is a secret code that only the operator 40 can know, and is not known to others.

  The decryption key management computer 20 stores the decryption key 120 transmitted from the operation terminal 30 in the database 150 in the management computer. At this time, the stored decryption key 120 is encrypted using the passcode 140 transmitted from the operation terminal 30 as encryption information for encryption. At this time, the encrypted decryption key 120 cannot be returned to a usable state without inputting the passcode 140. Next, the decryption key management computer 20 adds a character string of a random and unique value (non-overlapping value) to the passcode 140 to generate an identification code 160 and stores it in the database 150 in association with the decryption key 120. .

  Here, any method may be used as a method of encrypting the decryption key 120 using the passcode 140 as encryption information for encryption. In order to increase the encryption strength of encryption, a method of giving fluctuation to the encryption logic based on a certain value is usually adopted. This is usually called a seed. As a result, even if the data to be encrypted is the same, different encryption results can be obtained, which has the effect of preventing exposure to others. Here, for example, by using the passcode 140 as a seed, the passcode 140 is required even during decryption, and the decryption key 120 can be prevented from being stolen by a third party who cannot know the passcode 140.

  The reason why the identification code 160 is generated by adding a random and unique character string to the pass code 140 is as follows. Since the passcode 140 is determined by a human, it may be possible to specify the same value by chance even when a different person determines. Therefore, uniqueness is ensured by adding a logically non-overlapping value to the passcode 140.

  In the present embodiment, the pass code 140 is transmitted from the operation terminal 30 to the decryption key management computer 20, and a character string is added to the pass code 140 to generate the identification code 160. Can be generated independently in the decryption key management computer 20. In the decryption key management computer 20, the decryption key 120 is encrypted using the passcode as encryption information, but may be stored without being encrypted. However, the security is naturally enhanced when the decryption key 120 is encrypted and stored.

  Next, as shown in FIG. 5, the decryption key management computer 20 transmits the identification code 160 to the operation terminal 30 (step 503). The operation terminal 30 displays or stores the identification code 160 on a display screen or a data storage medium. The operator 40 can obtain the identification code 160 using the operation terminal 30.

  Next, as shown in FIG. 6, the operation terminal 30 creates an archive 170 including the business application 100 in order to execute the business AP (application) 100 in the business execution computer 10 (step 504). At this time, the archive 170 includes secret information 130 encrypted using the encryption key 110. The archive 170 also stores an identification code 160 generated when the decryption key management computer 20 registers the decryption key 120 in the database 150. Next, the operation terminal 30 transmits the archive 170 to the business execution computer 10 (step 505). Here, the archive 170 means an associated file group in which a plurality of files are associated and transmitted / received as one piece of information.

  The business execution computer 10 that has received the archive 170 acquires from the archive 170 the confidential information 130 and the identification code 160 that are encrypted using the respective programs and the encryption key 110 necessary for the execution of the business application 100. If the business is not started immediately, the business execution computer 10 stands by in a state where these pieces of information are stored.

  Next, when the business is started, as shown in FIG. 7, the business application 100 requests the decryption unit 180 to decrypt the secret information 130 in order to use the secret information 130. Upon receiving the decryption request from the business application 100, the decryption unit 180 requests the decryption key management computer 20 to acquire the decryption key 120 of the secret information 130 encrypted using the encryption key 110 (step 506). . At this time, the decryption unit 180 acquires the identification code 160 transmitted in the steps shown in FIG. 6 and the public key 190 of the business execution computer 10 preset in the business execution computer 10, and stores the decryption key 120. Attach to the acquisition request.

  Next, as shown in FIG. 8, the decryption key management computer 20 searches the database 150 using the identification code 160 transmitted in the step of FIG. 7 as a key. Next, the decryption key management computer 20 extracts the pass code 140 from the identification code 160. Since the retrieved decryption key 120 is encrypted using the passcode 140 as encryption information, the passcode 140 extracted from the identification code 160 is input and the decryption key 120 is decrypted and acquired.

  Next, referring to FIG. 9, the decryption key management computer 20 encrypts the decryption key 120 using the public key 190 transmitted from the business execution computer 10 in the step of FIG. 7 using a known public key encryption algorithm. The key 200 is generated (step 507). Next, the decryption key management computer 20 transmits the key 200 to the business execution computer 10 (step 508).

  Next, as shown in FIG. 10, the decryption unit 180 of the business execution computer 10 receives the key 200 transmitted in the step of FIG. 9 and sets it in advance with the public key 190 of the business execution computer 10. Using the secret key 210 thus obtained, the key 200 is decrypted to obtain the decryption key 120 (step 509). Next, the decryption unit 180 decrypts the encrypted secret information 130 using the decryption key 120 (step 510), and makes it usable by the business application 100. The business application 100 executes a business program using the decrypted secret information 130 (step 511).

  Note that the decryption key 120 is transmitted between the decryption key management computer 20 and the business execution computer 10 using the public key cryptosystem. The purpose is to prevent the decryption key 120 from leaking to a third party even if communication is intercepted between the two. Although not specifically described, even when the decryption key 120 is transmitted from the operation terminal 30 to the decryption key management computer 20, a known security mechanism such as SSL (Secure Sockets Layer) is used on the communication path. Ensure safety.

  According to the business execution system of the present embodiment, since the decryption key 120 for automatically decrypting the secret information 130 is acquired at the time of business execution, the operator 40 instructs the business execution on the operation terminal 30. It is only necessary to transmit the archive 170 for this purpose to the business execution computer 10. This eliminates the need for the operator 40 to wait until the operation can be executed on the operation terminal 30, leading to cost reduction such as personnel costs. Further, since the business execution computer 10 automatically executes the business, an operator is not involved, and a malicious operator can prevent a threat of stealing information in the process of decrypting secret information.

  Further, when the secret information 130 is not used, it is stored in an encrypted and inoperable state and is decrypted only when necessary at the time of business execution. Even if it is invaded, the possibility that the secret information 130 is stolen is low, and safety can be improved.

  Furthermore, since the encrypted secret information 130 is stored in the business execution computer 10 and the decryption key 120 for decrypting the encrypted secret information 130 is stored in the decryption key management computer 20, the secret information In order to obtain 130 illegally, it is necessary to intrude into the two computers 10 and 20, which is difficult to execute for security reasons.

  Next, an operation when a failure occurs in the active business execution computer 10 and business processing is performed by the standby business execution computer 11 will be described with reference to FIG. Here, the case where any failure occurs in the business execution computer 10 is not only a case where an operation failure occurs and the normal operation cannot be performed, but also business processing from a plurality of operation terminals. A case where requests concentrate and the allowable processing amount of the business execution computer 10 is exceeded is also included.

  The process until the business application 100, the archive 170 including the encrypted secret information 130 and the identification code 160 is transmitted from the operation terminal 30 to the business execution computer 10 is the same as the process shown in FIG. Since there is, explanation is omitted. When the business execution computer 10 falls into an inoperable state, the business execution computer 10 is a substitute computer for the business execution computer 10 so that the business application 100 is continuously operated. A copy of the archive 170 is sent to the computer 11. At this time, the operation terminal 30 and the business execution computer 11 do not need to be connected to each other.

  Upon receiving the archive 170, the business execution computer 11 receives the notification and executes the application 100 on behalf of the business execution computer 10 when the business execution computer 10 becomes unable to execute the business application 100 due to some failure. To do. At this time, since the secret information 130 transferred to the business execution computer 11 is in an encrypted state, it cannot be used as it is from the business application 100.

  The business application 100 executed by the business execution computer 11 obtains the decryption key 120 of the encrypted secret information 130 from the decryption key management computer 20 in the same manner as when the business execution computer 10 operates, and the secret information 130 is decrypted to be usable by the business application 100. However, at this time, as described in the step of FIG. 9, the decryption key 120 is encrypted with the public key using the public key preset in the business execution computer 11, and the encrypted decryption key 120 is decrypted. This is performed with a secret key previously set in a pair with the public key in the business execution computer 11. Further, it is assumed that the business execution computer 11 and the decryption key management computer 20 are connected to each other.

  As described above, this method can also be applied to the operation terminal 30 operated by the operator 40 and the business execution computer 11 that is not connected to each other. Even if a problem occurs, it is possible to execute business processing.

  Furthermore, a case where the business execution computer 10 is configured by different software, which is divided into processing related to the present invention and general processing not directly related to the present invention, will be described with reference to FIG.

  FIG. 12 shows a case where the software for performing the processing of the business execution computer 10 is configured by a business program 301 and middleware 302.

  The business program 301 is a program for performing general processing not directly related to the present invention, and the middleware 302 receives the processing related to the present invention, that is, the archive 170 from the operation terminal 30 and receives the decryption key management computer 20. Is a software that performs a process of transmitting a request for obtaining the decryption key 120, receiving the key 200, decrypting the key 200, obtaining the decryption key 120, and decrypting the secret information 130. In this way, the middleware 302 transfers the acquired business application 100 and secret information 130 to the business program 301, and the business program 301 executes business processing using the business application 100 and secret information 130.

  As shown in FIG. 12, the business program 301 for performing business processing and the middleware 302 are configured by different software, so that the present invention can be realized only by adding middleware to a conventional business execution computer. It is possible to realize a business execution computer that executes

  Further, in the present embodiment, the case of multiplexing by the two business execution computers 10 and 11 has been described, but the present invention is not limited to such a case, and three or more computers are used. The present invention can be similarly applied even when multiplexed by a business execution computer.

It is a block diagram which shows the structure of the secret information management system of one Embodiment of this invention. It is a sequence chart which shows operation | movement of the business execution system of FIG. It is a figure for demonstrating operation | movement of one Embodiment of this invention. It is a figure for demonstrating operation | movement of one Embodiment of this invention. It is a figure for demonstrating operation | movement of one Embodiment of this invention. It is a figure for demonstrating operation | movement of one Embodiment of this invention. It is a figure for demonstrating operation | movement of one Embodiment of this invention. It is a figure for demonstrating operation | movement of one Embodiment of this invention. It is a figure for demonstrating operation | movement of one Embodiment of this invention. It is a figure for demonstrating operation | movement of one Embodiment of this invention. It is a figure for demonstrating operation | movement when a failure generate | occur | produces in the business execution computer 11 in the secret information management system of one Embodiment of this invention. It is a figure for demonstrating the case where the computer 10 for business execution is comprised with the business program 301 and the middleware 302. FIG.

Explanation of symbols

10, 11 Business execution computer 20 Decryption key management computer 30 Operation terminal 40 Operator 100 Business application (AP)
110 Encryption Key 120 Decryption Key 130 Secret Information 140 Pass Code 150 Database 160 Identification Code 170 Archive 180 Decryption Unit 190 Public Key 200 Key 210 Private Key 301 Business Program 302 Middleware 501 to 511 Steps

Claims (6)

A business execution system in which a business execution computer that receives a business processing request from an operation terminal executes business processing,
When the decryption key is received from the operation terminal, the identification code for specifying the decryption key is stored in association with the identification key, the identification code is transmitted to the operation terminal, and a decryption key acquisition request from the business execution computer is transmitted. Upon receipt, a decryption key management computer that searches for a decryption key corresponding to the identification code included in the decryption key acquisition request and transmits the decryption key acquisition request to the business execution computer,
Encrypts secret information to be processed with an encryption key, sends a decryption key for decrypting the encrypted secret information to the decryption key management computer, and requests the business execution computer for the business process An operation terminal for transmitting a file group including a business application program, encrypted secret information, and an identification code received from the decryption key management computer to the business execution computer;
When it is determined that the business process cannot be executed when receiving the file group from the operation terminal and performing the business process, the received file group is transferred to the spare business execution computer, and the business process is executed. When it is determined that the decryption key can be received, a decryption key acquisition request is made by transmitting an identification code included in the file group received from the operation terminal to the decryption key management computer, and the decryption key from the decryption key management computer is obtained. When received, the business execution computer that decrypts the secret information included in the file group with the decryption key and processes the decrypted secret information based on the business application program,
When a file group is transferred from the business execution computer, a decryption key acquisition request is made by transmitting an identification code included in the transferred file group to the decryption key management computer, and the decryption key management computer Upon receiving the decryption key from, it decrypts the secret information contained in the file group by the decoding key, the secret information which is decoded and a spare business executing computer processing based on the business application program ,
The operation terminal, when transmitting a decryption key to the decryption key management computer, transmits an arbitrarily selected passcode,
The decryption key management computer encrypts the passcode received from the operation terminal as encryption information, adds a character string of a unique value to the passcode as the identification code, and from the business execution computer When the decryption key acquisition request is received, the business execution system decrypts the decryption key using the passcode extracted from the identification code included in the decryption key acquisition request . When the business execution computer and the spare business execution computer transmit a decryption key acquisition request to the decryption key management computer, the public key set for each of the business execution computers is used. Attached and sent to the decryption key management computer,
When the decryption key management computer transmits a decryption key to each business execution computer, the decryption key management computer encrypts the decryption key with the public key attached to the decryption key acquisition request and transmits the decryption key to the business execution computer.
Upon receiving the encrypted decryption key from the decryption key management computer, each of the business execution computers decrypts the encrypted decryption key using a secret key corresponding to the public key and obtains the decryption key task execution system of claim 1, wherein the acquiring. A business execution method for executing a business process on a business execution computer in response to a business process request from an operation terminal,
In the operation terminal, encrypting secret information to be processed with an encryption key, and transmitting a decryption key for decrypting the encrypted secret information to a decryption key management computer;
The decryption key management computer stores the decryption key received from the operation terminal in association with the identification code for specifying the decryption key and transmits the identification code to the operation terminal;
When requesting business processing to the business execution computer, the operation terminal includes a file group including a business application program, encrypted secret information, and an identification code received from the decryption key management computer. Sending to the business execution computer;
When the business execution computer that has received the file group from the operation terminal determines that the business process cannot be executed when attempting to perform the business process, the received file group is transferred to the spare business execution computer. Steps,
The backup business execution computer to which the file group has been transferred performs a decryption key acquisition request by transmitting an identification code included in the transferred file group to the decryption key management computer;
The decryption key management computer that has received the decryption key acquisition request searches for a decryption key corresponding to the identification code included in the decryption key acquisition request, and transmits it to the spare business execution computer that has transmitted the decryption key acquisition request. And steps to
A spare business execution computer receiving the decryption key from the decryption key management computer decrypts the secret information contained in the file group with the decryption key;
The spare business execution computer processing the decrypted secret information based on the business application program ;
The operation terminal, when transmitting a decryption key to the decryption key management computer, transmitting an arbitrarily selected passcode;
The decryption key management computer encrypts the passcode received from the operation terminal using encryption information, adds a character string of a unique value to the passcode as the identification code, and from the business execution computer A decryption key is decrypted by using the passcode extracted from the identification code included in the decryption key acquisition request when the decryption key acquisition request is received . When the business execution computer and the spare business execution computer transmit a decryption key acquisition request to the decryption key management computer, the public keys respectively set for the business execution computers Attaching and transmitting to the decryption key management computer;
When the decryption key management computer transmits a decryption key to each business execution computer, it is encrypted with the public key attached to the decryption key acquisition request and transmitted to each business execution computer When,
Upon receiving the encrypted decryption key from the decryption key management computer, each of the business execution computers decrypts the encrypted decryption key using a secret key corresponding to the public key and obtains the decryption key The business execution method according to claim 3 , further comprising a step of acquiring. A program for causing a computer to execute a business execution method for executing a business process on a business execution computer in response to a business process request from an operation terminal,
In the operation terminal, a process of encrypting secret information to be processed with an encryption key and transmitting a decryption key for decrypting the encrypted secret information to a decryption key management computer;
A process in which the decryption key management computer stores the decryption key received from the operation terminal in association with the identification code for specifying the decryption key and transmits the identification code to the operation terminal;
When requesting business processing to the business execution computer, the operation terminal includes a file group including a business application program, encrypted secret information, and an identification code received from the decryption key management computer. Processing to be sent to the business execution computer;
When the business execution computer that has received the file group from the operation terminal determines that the business process cannot be executed when attempting to perform the business process, the received file group is transferred to the spare business execution computer. Processing,
A process in which a spare business execution computer to which the file group has been transferred performs a decryption key acquisition request by transmitting an identification code included in the transferred file group to the decryption key management computer;
The decryption key management computer that has received the decryption key acquisition request searches for a decryption key corresponding to the identification code included in the decryption key acquisition request, and transmits it to the spare business execution computer that has transmitted the decryption key acquisition request. Processing to
A backup job execution computer that has received the decryption key from the decryption key management computer decrypts the secret information contained in the file group using the decryption key;
A process in which the spare business execution computer performs business processing on the decrypted secret information based on the business application program ;
A process of transmitting an arbitrarily selected passcode when the operation terminal transmits a decryption key to the decryption key management computer;
The decryption key management computer encrypts the passcode received from the operation terminal using encryption information, adds a character string of a unique value to the passcode as the identification code, and from the business execution computer When the decryption key acquisition request is received, a program for causing the computer to execute a process of decrypting the decryption key using the passcode extracted from the identification code included in the decryption key acquisition request . When the business execution computer and the spare business execution computer transmit a decryption key acquisition request to the decryption key management computer, the public keys respectively set for the business execution computers Processing to attach and transmit to the decryption key management computer;
When the decryption key management computer transmits a decryption key to each business execution computer, it is encrypted with the public key attached to the decryption key acquisition request and transmitted to each business execution computer When,
Upon receiving the encrypted decryption key from the decryption key management computer, each of the business execution computers decrypts the encrypted decryption key using a secret key corresponding to the public key and obtains the decryption key The program according to claim 5 , further causing the computer to execute the process of acquiring.

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