JP2014011739A - Computing system and calculation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a computing system which prevents confidential information from being leaked when the system is attacked while executing a program of which data and program itself exceed capacity of a tamper resistant device.SOLUTION: A computing system comprises: a tamper resistant device which manages an encryption key; and a server which stores a program and data encrypted by the encryption key. The tamper resistant device performs decryption processing on the encrypted program and data acquired from the server by the encryption key.

Description

  The present invention relates to a computer system and a calculation method, and more particularly to a computer system and a calculation method for ensuring the security of a system that handles highly confidential information such as personal information.

  In a system that handles highly confidential data such as personal information, conventionally, the data is encrypted and stored, and the encryption key is managed by a tamper resistant device (HSM: hardware security module) (see, for example, Patent Document 1). ). The capacity of the HSM is small, and only minimum processing such as encryption processing is performed within the HSM, and other processing is performed outside the HSM.

JP 2012-5037 A

  In a system that handles highly confidential data such as personal information, the data is encrypted and stored. However, at the time of execution, the data needs to be decrypted and processed. If all processing can be performed inside the tamper resistant device (HSM), it will not be a problem that the confidential information becomes plaintext at the time of execution, but the capacity of the HSM is small and large-scale programs and data should be stored in the HSM. Since it was impossible, it was impossible to perform the processing other than the minimum processing such as cryptographic computation in the HSM. Therefore, there was a risk of leaking confidential information when attacked at the time of execution.

  Accordingly, an object of the present invention made in view of such a point is to provide a computer system and a calculation method capable of preventing leakage of confidential information against an attack at the time of executing a program or data exceeding the capacity of a tamper resistant device. It is to provide.

  In order to solve the above-described problems, a computer system according to the present invention includes a tamper resistant device that manages an encryption key, and a server that stores a program and data encrypted with the encryption key. The apparatus is characterized in that the encrypted program and data acquired from the server are decrypted with the encryption key and processed.

  The program is preferably divided into lines and encrypted.

  Further, it is desirable that the program is divided into function-based scripts and encrypted.

  Furthermore, in order to solve the above-described problems, a calculation method according to the present invention is a calculation method of a computer system including a tamper-proof device that manages a secret key and a server, wherein the server is configured to store the secret key. Storing the program and data encrypted with a public key, and the tamper-proof device decrypting the encrypted program and data acquired from the server with the secret key and processing the data. It is characterized by that.

  The program is preferably divided into lines and encrypted.

  Further, it is desirable that the program is divided into function-based scripts and encrypted.

  According to the computer system and the calculation method of the present invention, it is possible to prevent leakage of confidential information against an attack at the time of executing a program or data exceeding the capacity of the tamper resistant device. In particular, encryption with an encryption key can prevent a threat that an illegal program is encrypted with a public key and read into the HSM.

It is a figure which shows schematic structure of the computer system which concerns on one Embodiment of this invention. It is a figure which shows an example of program encryption. It is a processing sequence of key generation of a computer system. It is a processing sequence of program encryption of a computer system. It is a processing sequence of data encryption of a computer system. It is a processing sequence of the computer system program execution.

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

  FIG. 1 is a diagram showing a schematic configuration of a computer system according to an embodiment of the present invention. The computer system includes an encryption terminal 10, a server 20, an HSM 30 that is a tamper resistant device, and a client 40. The encryption terminal 10 encrypts the program and data and stores them in the server 20. The server 20 transmits the encrypted “row” and data necessary for processing to the HSM 30 in accordance with the processing request from the client 40. The HSM 30 decrypts the encrypted “row” and data sent from the server 20 and executes the data after confirming the validity. The executed data is encrypted and stored in the server 20. Hereinafter, the configuration of the encryption terminal 10, the server 20, the HSM 30, and the client 40 will be described in detail.

  The encryption terminal 10 includes a program encryption unit 11, a data encryption unit 12, and a “row” / data transmission unit 13. The program encryption unit 11 receives a program encryption command from the client 40. The data encryption unit 12 receives a data encryption command from the client 40. The “row” / data transmission means 13 transmits the encrypted “row” and data to the server 20 in order to save them in the server 20.

  The program encryption unit 11 includes a program division unit 111, a hash generation / addition unit 112, a line number addition unit 113, and a result notification unit 114. FIG. 2 is a diagram illustrating an example of program encryption. (1) The program dividing unit 111 divides the program in units of lines. (2) The hash generation / addition unit 112 adds a “row” validity identification tag to each row. The “row” validity identification tag is a hash value of “row” obtained by dividing the program. (3) The data encryption unit 12 encrypts “row + row validity identification tag”. An encrypted “row + row validity identification tag” is referred to as an encrypted “row”. (4) The line number adding means 113 adds a line number used when calling an encrypted “line” from the client 40. The line number is the line number of each line when the program is divided into line units. The result notifying unit 114 notifies the client 40 that the program encryption is successful.

  The server 20 includes “row” / data transfer means 21, “row” / data storage means 22, “row” storage 23, and data storage 24. The “row” / data transfer means 21 encrypts the “row” encrypted from the “row” storage 23 and the data storage 24 in accordance with the processing request from the client 40 and the “row” / data transfer request from the HSM 30. Transfer data to HSM 30. The “row” / data storage means 22 stores the encrypted “row” and data in the “row” storage 23 and the data storage 24. The “row” storage 23 stores the encrypted “row”. The data storage 24 stores the encrypted data.

  The HSM 30 includes an encryption key generation unit 31, a decryption unit 32, a hash collation unit 33, a “row” execution unit 34, a data encryption unit 35, a data transmission unit 36, and a “row” / data request unit 37. And an encryption key storage 38 and encryption means 39. The encryption key generation means 31 generates an encryption key used for program and data encryption and decryption. The decryption means 32 decrypts the encrypted “row” and data with the encryption key stored in the encryption key storage 38. The hash collating unit 33 takes the hash of the “row” portion (the portion excluding the “row” validity identification tag) of the decrypted “row”, and the hash generation / addition unit 112 of the encryption terminal 10. Confirm that the “line” legitimacy identification tag added by matches. The “row” execution means 34 processes the decoded “row” and data. The data encryption unit 35 encrypts the processed data with the encryption key stored in the encryption key storage 38. The data transmission unit 36 transmits the encrypted processed data to the “row” / data storage unit 22 in order to store the data in the data storage 24 of the server 20. The “line” / data request means 37 sends the encrypted “line” with the corresponding line number added to the “line” of the server 20 according to the line number / data name called during execution of the “line”. A function for receiving from the data transfer means 21 and passing it to the decryption means 32 together with an argument, and a function for transmitting the processing result to the “row” / data transfer means 21 of the server 20 when there is no “row” / data to be requested next. have. The encryption key storage 38 stores the encryption key generated by the encryption key generation unit 31. The encryption unit 39 encrypts and returns the input from the program encryption unit 11 and the data encryption unit 12 with the encryption key stored in the encryption key storage 38.

  The client 40 includes an encryption key generation request unit 41, a program encryption request unit 42, a data encryption request unit 43, and a processing request transmission unit 44. The encryption key generation request unit 41 transmits an encryption key generation request from the user to the HSM 30. The program encryption request unit 42 requests the encryption terminal 10 to encrypt a program input as a source code from the user. The data encryption request unit 43 requests the encryption terminal 10 to encrypt data input by the user. The processing request transmission unit 44 transmits the user's processing request (row number, data location information in the data storage 24) to the “row” / data transfer unit 21 of the server 20.

  Hereinafter, the operation of each component will be described together with the processing sequence of the computer system.

(Key generation)
FIG. 3 is a processing sequence of key generation performed as pre-processing of the computer system. Upon receiving the encryption key generation request from the user, the encryption key generation request unit 41 of the client 40 requests key generation from the encryption key generation unit 31 of the HSM 30 (step S101). The encryption key generation means 31 of the HSM 30 generates an encryption key and stores the encryption key in the encryption key storage 38 (steps S102 and S103). The encryption key generation unit 31 notifies the encryption key generation request unit 41 of the client 40 that the storage has been successful (step S104). The encryption key generation request unit 41 returns a result that the encryption key generation was successful to the user (step S105).

(Program encryption)
FIG. 4 is a processing sequence of program encryption performed as pre-processing of the computer system. When the program (source code) is received from the user, the program encryption request unit 42 of the client 40 requests the program encryption unit 11 of the encryption terminal 10 to encrypt the program (step S201). The program dividing unit 111 of the program encryption unit 11 divides the program in units of lines (step S202). The hash generation / addition unit 112 takes the hash of “row” and adds it as a “row” validity identification tag (step S203). The program encryption unit 11 requests the encryption unit 39 of the HSM 30 to encrypt ““ row ”+“ row ”validity identification tag” (step S204). An encrypted “line” + “line” validity identification tag ”is referred to as an encrypted“ line ”. The encryption means 39 encrypts using the encryption key stored in the encryption key storage 38, and returns the encrypted “row” to the program encryption means 11 of the encryption terminal 10 (step S205). The line number adding unit 113 of the program encryption unit 11 adds a line number to the encrypted “line” (step S206). The program encryption unit 11 requests the “row” / data transmission unit 13 to transmit the encrypted “row” + “row” identifier to the “row” / data storage unit 22 of the server 20. The “row” / data transmission unit 13 requests the “row” / data storage unit 22 of the server 20 to save the “row” (step S207). The “row” / data storage means 22 of the server 20 stores the encrypted “row” + “row” identifier in the “row” storage 23, and when the storage is completed, the “row” / data storage means 22 of the encryption terminal 10. The data is transmitted to the data transmission means 13 (step S208). The result notifying unit 114 of the program encryption unit 11 transmits the “row” identifier to the program encryption request unit 42 of the client 40 (step S209). The program encryption request means 42 stores the “row” identifier (step S210), and returns a result of successful encryption to the user (step S211).

  FIG. 5 is a data encryption processing sequence performed as pre-processing of the computer system. When receiving data from the user, the data encryption requesting means 43 of the client 40 requests the data encryption means 12 of the encryption terminal 10 to encrypt the data (step S301). The data encryption unit 12 requests the encryption unit 39 of the HSM 30 to encrypt the data (step S302). The encryption means 39 encrypts using the encryption key stored in the encryption key storage 38, and returns the encrypted data to the data encryption means 12 of the encryption terminal 10 (step S303). The data encryption unit 12 requests the “row” / data transmission unit 13 to transmit the encrypted data to the “row” / data storage unit 22 of the server 20. Requests the “row” / data storage means 22 of the server 20 to save the encrypted data (step S304). The “row” / data storage means 22 of the server 20 saves the encrypted data in the data repository 24, and when the saving is completed, the encrypted data is transmitted to the “row” / data transmission means 13 of the encryption terminal 10 (step S305). ). The data encryption unit 12 notifies the data encryption request unit 43 of the client 40 that the encryption is successful (step S306). The data encryption request unit 43 returns a result that the encryption is completed to the user (step S307). Note that the result includes location information of the encrypted data in the data storage 24.

(Program execution)
FIG. 6 is a processing sequence of the computer system program execution. Upon receiving the line number and the position information of the data to be processed in the data storage 24 from the user, the processing request transmission means 44 of the client 40 sends a processing request including the line number and the position information of the data to be processed in the data storage 24. The data is transmitted to the “row” / data transfer means 21 of the server 20 (step S401). The “row” / data transfer means 21 transmits the encrypted “row” and the encrypted data from the “row” storage 23 and the data storage 24 to the decryption means 32 of the HSM 30 in accordance with the processing request (step S402). ). The decryption means 32 of the HSM 30 decrypts the transferred encrypted “row” and the encrypted data using the encryption key stored in the encryption key storage 38 (step S403). The hash collation means 33 takes the hash of the “row” portion of the decrypted “row” (the portion excluding the “row” legitimacy identification tag), and collates the hash with the “row” legitimacy identification tag to match. It is confirmed whether to do (step S404). The “row” execution unit 34 executes “row” (step S405). The data encryption means 35 encrypts the processed data using the encryption key stored in the encryption key storage 38 (step S406). The data transmission unit 36 transmits the encrypted data to the “row” / data storage unit 22 of the server 20 (step S407). The “row” / data storage unit 22 of the server 20 stores the encrypted data in the data storage 24, and when completed, notifies the data transmission unit 36 of the HSM 30 that the storage is complete (step S408). If the “line” content is the end of the program (for example, END), the “line” / data request unit 37 proceeds to step S411 (Yes in step S409).

The “line” / data request unit 37 performs the following process when the “line” content is other than the program end (No in step S409).
(1) If there is an instruction to move to a specific line number during execution of “line” (for example, forced movement (GOTO), conditional branch (IF), loop (FOR), subroutine branch (GOSUB), etc.), the corresponding line The “row” of the number is requested to the “row” / data transfer means 21 of the server 20.
(2) If there is necessary data during execution of “row”, a request is made to the “row” / data transfer means 21 of the server 20 based on the position information of the corresponding data in the data storage 24.
(3) If there is no command to move to a specific line number, a request is made to the “line” / data transfer means 21 of the server 20 for the “line” next to the executed “line”.

  The “row” / data transfer means 21 sends the corresponding encrypted “row” and encrypted data to the “row” / data request according to the passed row number and the location information of the data in the data storage 24. It passes to the means 37 (step S410). The “row” / data request unit 37 passes the encrypted “row” and the encrypted data to the decryption unit 32, and the process returns to step S403.

  When the program ends, the “row” / data request unit 37 transmits the return value of “row” to the “row” / data transfer unit 21 of the server 20 (step S411). The “row” / data transfer unit 21 returns the processing result to the processing request transmission unit 44 of the client 40 (step S412). The processing request transmission unit 44 returns the processing result to the user (step S413).

  Thus, according to the present embodiment, the server 20 stores the program and data encrypted with the encryption key, and the HSM 30 that is the tamper resistant device encrypts the encrypted program and data acquired from the server 20. Decrypt with key and process. As a result, programs and data that operate in the HSM 30 can be stored in the external storage (server 20) of the HSM 30 having a large capacity, so that programs and data that exceed the capacity of the HSM 30 can be safely executed in the HSM 30. It becomes. In other words, it is possible to prevent leakage of confidential information against attacks during program execution. In particular, unlike public keys, encryption keys are not available to everyone. That is, the encryption with the encryption key can prevent a threat that an illegal program is encrypted with the public key and read into the HSM.

  The above-described program to be encrypted is divided and encrypted in units of lines. As a result, the HSM 30 can exchange the encrypted program with the external storage (server 20) for each programally meaningful group.

  Although the present invention has been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various modifications and corrections based on the present disclosure. Therefore, it should be noted that these variations and modifications are included in the scope of the present invention. For example, functions included in each member, each means, each step, etc. can be rearranged so as not to be logically contradictory, and a plurality of means, steps, etc. can be combined or divided into one. Is possible.

  For example, in the above-described embodiment, the program encryption unit 11 divides the program into lines and performs encryption. This is an example for a so-called procedural language, and the present invention can be applied to other functional languages. For example, when the present invention is applied to a functional language, the program encryption unit 11 divides the program into scripts in units of functions, and instead of “rows”, hash generation / addition or script identifier is added to the script. Should be added. The script identifier is an identifier used when calling a script from the client 40, such as a line number added when dividing the script into line units. For example, the script identifier is a function name after conversion of each script when the function name of the program is converted and the program into which the function name is converted is divided into scripts for each function. In this way, by dividing the above-described encrypted program into functional unit scripts and encrypting them, the HSM 30 can program the external storage (server 20) and the encrypted program for each meaningful program. Can be exchanged.

  The encryption terminal 10 can also be implemented as part of the functions of the client 40 and the server 20. Further, the server 20 may perform the subject that performs the encryption key generation command and the program and data encryption command.

DESCRIPTION OF SYMBOLS 10 Terminal for encryption 11 Program encryption means 111 Program division means 112 Hash generation / addition means 113 Line number addition means 114 Result notification means 12 Data encryption means 13 “Row” / data transmission means 20 Server 21 “Row” / data Transfer means 22 “Row” / data storage means 23 “Row” storage 24 Data storage 30 HSM
Reference Signs List 31 encryption key generation means 32 decryption means 33 hash collation means 34 “row” execution means 35 data encryption means 36 data transmission means 37 “row” / data request means 38 encryption key storage 39 encryption means 40 client 41 encryption key generation Request means 42 Program encryption request means 43 Data encryption request means 44 Processing request transmission means

Claims (6)

A tamper resistant device for managing encryption keys;
A server storing a program and data encrypted with the encryption key,
The computer system, wherein the tamper resistant apparatus decrypts the encrypted program and data acquired from the server with the encryption key and processes the encrypted program and data.   The computer system according to claim 1, wherein the program is divided into lines and encrypted.   The computer system according to claim 1, wherein the program is divided into functional scripts and encrypted. A calculation method for a computer system comprising a tamper resistant device for managing a secret key and a server,
The server storing a program and data encrypted with a public key of the private key;
The tamper resistant device includes a step of decrypting and processing the encrypted program and data acquired from the server with the secret key.   The calculation method according to claim 4, wherein the program is divided into lines and encrypted.   The calculation method according to claim 4, wherein the program is divided into function-based scripts and encrypted.

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