Instruction conversion device, instruction conversion system, and instruction conversion method

Abstract

Even if a replacement cryptographic mechanism for a compromised cryptographic mechanism is implemented in a cryptographic device, it does not require any changes to the IT equipment that uses the cryptographic device, and the IT equipment can use the replacement cryptographic mechanism added to the cryptographic device. [Solution] When the instruction conversion device 10 receives a first cryptographic service instruction from the IT device 11 that specifies at least one cryptographic mechanism 120, it checks whether the cryptographic mechanism 120 specified in the first cryptographic service instruction is described in the instruction conversion table 101 as a compromised cryptographic mechanism 120c. If the cryptographic mechanism 120 specified in the first cryptographic service instruction is a compromised cryptographic mechanism 120c, the instruction conversion unit 100 sends a second cryptographic service instruction to the cryptographic device 12, which converts the cryptographic mechanism 120 specified in the first cryptographic service instruction to its alternative cryptographic mechanism 120d.

Description

Technical Field

[0001] This application relates to a technology for realizing Crypto Agility.

Background Art

[0002] In IT devices that utilize IT (IT: Information Technology), cryptographic mechanisms have become indispensable. In this application, the cryptographic mechanism refers to a series of procedures and methods used to keep information secret. Types of cryptographic mechanisms include symmetric key cryptography, public key cryptography, and signature generation.

[0003] IT devices that require cryptographic mechanisms are demanded to have Crypto Agility in order to cope with various threats. Crypto Agility is a concept that refers to "cryptographic agility". This means the ability to quickly switch to a new and more secure cryptographic mechanism without making major changes to the IT device when the cryptographic mechanism used in the IT device is endangered.

[0004] In IT devices with strict security requirements, cryptographic devices that provide various cryptographic mechanisms are used. Such cryptographic devices are also called HSM (Hardware Security Module). In an IT device that uses a cryptographic device, the IT device is connected to the cryptographic device, and the cryptographic device executes the cryptographic mechanism requested by the IT device.

[0005] In the case of an IT device that uses a cryptographic device, when a security threat occurs in the cryptographic mechanism provided by the cryptographic device and the cryptographic mechanism is endangered, it is necessary to add a new cryptographic mechanism that can cope with the security threat to the cryptographic device. In Patent Document 1, by providing a cryptographic device management server that relays communication between an IT device (terminal device) and a plurality of cryptographic devices, a cryptographic device equipped with a newly implemented cryptographic mechanism that can cope with security threats can be easily added. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2012-64995 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] Some commercially available cryptographic devices support multi-tenant environments where multiple users can use them simultaneously. In the case of cryptographic devices that support multi-tenant environments, if the cryptographic mechanism provided by the device is compromised, it will be necessary to add a new cryptographic mechanism to the device to address the security threat. However, this will also require modifications to the IT equipment using the cryptographic device to invoke the new cryptographic mechanism. In the case of cryptographic devices that support multi-tenant environments, this modification is required for each IT device using the cryptographic device, and the cost of modifications to the IT equipment increases as the number of IT devices increases.

[0008] Therefore, in this application, even if the cryptographic mechanism implemented in the cryptographic device is compromised and a new cryptographic mechanism to address the security threat is added to the cryptographic device, it is not necessary to change the IT equipment that uses the cryptographic device, and the IT equipment can use the new cryptographic mechanism added to the cryptographic device. [Means for solving the problem]

[0009] The first invention, which solves the above-mentioned problems, is an instruction conversion device that relays communication between an encryption device that provides an encryption service using an encryption mechanism and an IT device that uses the encryption service. The instruction conversion device according to the first invention is characterized by comprising an instruction conversion table that describes at least a compromised encryption mechanism and an alternative encryption mechanism that replaces it, and an instruction conversion unit that, upon receiving a first encryption service instruction from the IT device that specifies at least an encryption mechanism, checks whether the encryption mechanism specified in the first encryption service instruction is described in the instruction conversion table as the compromised encryption mechanism, and if the encryption mechanism specified in the first encryption service instruction is the compromised encryption mechanism, converts the encryption mechanism specified in the first encryption service instruction to its alternative encryption mechanism, and transmits a second encryption service instruction converted to the alternative encryption mechanism to the encryption device. In order to solve the problems of the present application H, the instruction conversion device according to the first invention is provided with a function to call the encryption service of the encryption device by specifying an alternative encryption mechanism instead of the compromised encryption mechanism.

[0010] The second invention is characterized in that, in the instruction conversion device described in the first invention, a conversion formula for converting the key number of the encryption key used by the compromised encryption mechanism to the key number of the encryption key used by the alternative encryption mechanism is described in the instruction conversion table, the first encryption service instruction includes a key number that specifies the encryption key used in the encryption service, and the instruction conversion unit converts the key number specified in the first encryption service instruction to the corresponding key number of the alternative encryption mechanism according to the conversion formula described in the instruction conversion table, and transmits the second encryption service instruction, in which the encryption mechanism and key number have been converted, to the encryption device. The second invention is an invention that corresponds to an encryption mechanism that uses an encryption key.

[0011] The third invention is an instruction conversion device described in the first or second invention, characterized in that exclusion conditions indicating the conditions under which the compromised cryptographic mechanism is not converted to the alternative cryptographic mechanism are described in the instruction conversion table, an exclusion flag is included in the first cryptographic service instruction, and the instruction conversion unit transmits the first cryptographic service instruction with the exclusion flag removed to the cryptographic device if the value of the exclusion flag included in the first cryptographic service instruction conforms to the exclusion conditions described in the instruction conversion table. The third invention is an invention that addresses cases where it is necessary to use the compromised cryptographic mechanism as is.

[0012] The fourth invention is an instruction conversion system that includes an encryption device that provides an encryption service using an encryption mechanism, an IT device that uses the encryption service, and an instruction conversion device that relays communication between the encryption device and the IT device. The aforementioned IT device is a device that transmits a first cryptographic service instruction specifying at least a cryptographic mechanism to the instruction converter. The instruction conversion device is characterized by comprising an instruction conversion table that lists at least a compromised cryptographic mechanism and an alternative cryptographic mechanism that replaces it, and an instruction conversion unit that, upon receiving the first cryptographic service instruction from the IT device, checks whether the cryptographic mechanism specified in the first cryptographic service instruction is described in the instruction conversion table as the compromised cryptographic mechanism, and, if the cryptographic mechanism specified in the first cryptographic service instruction is the compromised cryptographic mechanism, transmits a second cryptographic service instruction to the cryptographic device, which converts the cryptographic mechanism specified in the first cryptographic service instruction to the alternative cryptographic mechanism. To solve the problems of the present invention, the instruction conversion device according to the fourth invention has a function to call the cryptographic service of the cryptographic device by specifying an alternative cryptographic mechanism in place of the compromised cryptographic mechanism.

[0013] The fifth invention is characterized in that, in the instruction conversion system described in the fourth invention, a conversion formula for converting the key number of the encryption key used by the compromised encryption mechanism to the key number of the encryption key used by the alternative encryption mechanism is described in the instruction conversion table, the first encryption service instruction includes a key number that specifies the encryption key used in the encryption service, and the instruction conversion unit converts the key number specified in the first encryption service instruction to the corresponding key number of the alternative encryption mechanism according to the conversion formula described in the instruction conversion table, and transmits the second encryption service instruction, in which the encryption mechanism and key number have been converted, to the encryption device. The fifth invention is an invention that corresponds to an encryption mechanism that uses an encryption key.

[0014] The sixth invention is characterized in that, in the instruction conversion system described in the fourth or fifth invention, exclusion conditions indicating the conditions under which the compromised cryptographic mechanism is not converted to the alternative cryptographic mechanism are described in the instruction conversion table, the first cryptographic service instruction includes an exclusion flag, and the instruction conversion unit transmits the first cryptographic service instruction with the exclusion flag removed to the cryptographic device if the value of the exclusion flag included in the first cryptographic service instruction conforms to the exclusion conditions described in the instruction conversion table. The sixth invention is an invention that addresses cases where it is necessary to use the compromised cryptographic mechanism as is.

[0015] The seventh invention is a method to be executed by an instruction converter that relays communication between an encryption device that provides an encryption service using an encryption mechanism and an IT device that uses the encryption service. The instruction converter method according to the seventh invention is characterized in that, when the instruction converter receives a first encryption service instruction from the IT device that specifies at least an encryption mechanism to be used in the encryption service, it checks whether the encryption mechanism specified in the first encryption service instruction is described as the compromised encryption mechanism in an instruction converter table that lists at least a compromised encryption mechanism and an alternative encryption mechanism that replaces it; and if the encryption mechanism specified in the first encryption service instruction is the compromised encryption mechanism, it sends a second encryption service instruction to the encryption device in which the encryption mechanism specified in the first encryption service instruction has been converted to the alternative encryption mechanism. In order to solve the problems of the present application, in the instruction converter method according to the seventh invention, the instruction converter executes a process to call the encryption service of the encryption device by specifying the alternative encryption mechanism instead of the compromised encryption mechanism.

[0016] The eighth invention is characterized in that, in the instruction conversion method described in the seventh invention, a conversion formula for converting the key number of the encryption key used by the compromised encryption mechanism to the key number of the encryption key used by the alternative encryption mechanism is described in the instruction conversion table, the first encryption service instruction includes the key number of the encryption key used in the encryption service, and in step b, the instruction conversion device converts the key number specified in the first encryption service instruction to the corresponding key number of the alternative encryption mechanism according to the conversion formula described in the instruction conversion table, and transmits the second encryption service instruction, in which the encryption mechanism and key number have been converted, to the encryption device. The eighth invention is an invention that corresponds to an encryption mechanism that uses an encryption key.

[0017] The ninth invention is characterized in that, in the instruction conversion method described in the seventh or eighth invention, an exclusion condition indicating a condition for not converting the jeopardized encryption mechanism into the alternative encryption mechanism is described in the instruction conversion table, an exclusion flag is included in the first encryption service instruction, and in step b, when the value of the exclusion flag included in the first encryption service instruction conforms to the exclusion condition described in the instruction conversion table, the instruction conversion device transmits the first encryption service instruction with the exclusion flag removed to the encryption device. The ninth invention is an invention that addresses cases where it is necessary to use the jeopardized encryption mechanism as it is.

Advantages of the Invention

[0018] In the invention disclosed in the present application, in order to solve the problems of the present application, a command conversion device that relays communication between an IT device and an encryption device is provided with a function of designating an alternative encryption mechanism instead of the jeopardized encryption mechanism.

Brief Description of the Drawings

[0019] [Figure 1] A diagram for explaining a command conversion system in which the command conversion device according to the present application is arranged. [Figure 2] A diagram showing the syntax of the second encryption service instruction. [Figure 3] A diagram showing a block diagram of the command conversion device. [Figure 4] A diagram for explaining the instruction conversion table stored in the storage. [Figure 5] A diagram showing the syntax of the first encryption service instruction. [Figure 6] A diagram for explaining the operation of the instruction conversion unit of the instruction conversion device. [Figure 7] A diagram showing an example of conversion of the encryption service instruction.

Embodiments for Carrying Out the Invention

[0020] Embodiments of the present invention will now be described. These embodiments are provided to facilitate understanding of the present invention, and the present invention is not limited to these embodiments. Unless otherwise specified, the drawings are schematic diagrams drawn to facilitate understanding of the present invention.

[0021] Figure 1 is a diagram illustrating an instruction conversion system 1 in which the instruction conversion device 10 according to the present invention is arranged. The instruction conversion system 1 shown in Figure 1 includes an encryption device 12 that supports a multi-tenant environment, a plurality of IT devices 11 that use the encryption device 12, and an instruction conversion device 10 that relays communication between the IT devices and the encryption device. In order to relay communication between the IT devices and the encryption device, the instruction conversion device 10 is connected to each of the plurality of IT devices 11 and further connected to the encryption device 12.

[0022] The cryptographic device 12 shown in Figure 1 is a device that provides cryptographic services using the cryptographic mechanism 120. In this application, a commercially available cryptographic device 12 can be used without modification. Therefore, a description of the hardware and other components of the cryptographic device 12 is omitted here.

[0023] The cryptographic services provided by the cryptographic device 12 include encryption, decryption, and signature generation. The cryptographic mechanisms 120 used for encryption and decryption are symmetric-key cryptography and public-key cryptography. Representative symmetric-key cryptography includes TDEA (Triple Data Encryption Algorithm) and AES (Advanced Encryption Standard). Representative symmetric-key cryptography includes RSA and ECC (Elliptic Curve Cryptography). The cryptographic mechanism 120 used for signature generation is a hash function. Representative hash functions include SHA256 and SHA384.

[0024] The cryptographic services provided by the cryptographic device 12 are invoked by cryptographic service instructions (commands) that call the cryptographic services. In this invention, the cryptographic service instruction that the instruction converter 10 sends to the cryptographic device 12 is called the second cryptographic service instruction. Figure 2 shows the syntax (format) of the second cryptographic service instruction. As shown in Figure 2, the syntax of the second cryptographic service instruction includes service specification information indicating the cryptographic service to be executed by the second cryptographic service instruction, and cryptographic mechanism specification information specifying the cryptographic mechanism 120 to be used by the cryptographic service. If parameters are required, the syntax of the second cryptographic service instruction includes the parameters used by the cryptographic mechanism 120. In addition, the second cryptographic service instruction can include data to be processed by the cryptographic service or a pointer to pass this data.

[0025] If the cryptographic service requested by the second cryptographic service instruction is encryption, for example, the service specification information is "Encrypt", and the cryptographic mechanism specification information is information that specifies the cryptographic mechanism 120 of target key cryptography or the cryptographic mechanism 120 of public key cryptography. In this embodiment, the information that specifies the cryptographic mechanism 120 is the name of the cryptographic mechanism 120 (for example, "TDEA"). If the cryptographic service requested by the second cryptographic service instruction is encryption, the syntax of the second cryptographic service instruction includes information that specifies the cryptographic key as a parameter. In this embodiment, the information that specifies the cryptographic key used for encryption is the unique key number of the cryptographic key stored in the cryptographic device 12. Similarly, if the cryptographic service requested by the second cryptographic service instruction is decryption, the syntax of the second cryptographic service instruction includes service specification information (for example, "Decrypt"), cryptographic mechanism specification information (for example, "TDEA"), and the key number. If the cryptographic processing requested by the second cryptographic service instruction is signature generation, for example, the service specification information is "Sign", and the cryptographic mechanism specification information is "SHA256".

[0026] The encryption device 12 according to this embodiment supports a multi-tenant environment that can be used by multiple users simultaneously. To realize a multi-tenant environment, the encryption device 12 securely manages users' encryption keys, isolating them from other users. Furthermore, the encryption device 12 that supports a multi-tenant environment has a function to authenticate users connected to the encryption device 12 in order to prevent unauthorized access to the encryption keys.

[0027] The IT equipment 11 shown in Figure 1 refers to equipment that utilizes IT. IT equipment 11 includes computer equipment such as computers and servers, communication equipment such as smartphones and routers, and input / output devices such as printers and scanners. Since general-purpose equipment can be used for IT equipment 11, a detailed explanation of the hardware of IT equipment 11 is omitted here.

[0028] If the cryptographic mechanism used in the cryptographic service provided by the cryptographic device 12 becomes compromised, the compromised cryptographic mechanism 120 must be replaced with a new, uncompromised cryptographic mechanism 120. In this application, the compromised cryptographic mechanism 120 is referred to as the compromised cryptographic mechanism 120c, and the cryptographic mechanism 120 that replaces it is referred to as the replacement cryptographic mechanism 120d. The replacement cryptographic mechanism 120d is of the same type as the compromised cryptographic mechanism 120c, but is more difficult to decrypt than the compromised cryptographic mechanism 120c. For example, the symmetric key cryptography "AES" can be used as the replacement cryptographic mechanism 120d for the symmetric key cryptography "TDEA".

[0029] As shown in Figure 1, when multiple IT devices 11 are connected to the encryption device 12, a change must be made for each IT device 11 to call the alternative encryption mechanism 120d newly implemented in the encryption device 12, which becomes a barrier to cryptoagility. Therefore, in the instruction conversion system 1 according to this embodiment, an instruction conversion device 10 is provided that has the function of converting an encryption service instruction that specifies a compromised encryption mechanism 120c into an encryption service instruction that specifies its alternative encryption mechanism 120d. This ensures that even when the alternative encryption mechanism 120d is newly implemented in the encryption device 12, no changes must be made to the IT devices 11 to call the alternative encryption mechanism 120d.

[0030] Figure 3 shows a block diagram of the instruction converter 10. The instruction converter 10 is a device implemented using a commercially available server. The instruction converter 10 includes at least a processor 104, RAM 102 (Random Access Memory), storage 105, and a communication interface 103. The processor 104 is an integrated circuit that has the function of executing computer programs. RAM 102 is the main memory used by the processor 104. Storage 105 is a large-capacity non-volatile memory. A hard disk or SSD (Solid State Drive) is used for storage 105. The communication interface 103 is an interface used for data communication with external devices. If the communication interface 103 used for data communication with IT equipment 11 and the communication interface 103 used for data communication with encryption device 12 are different, the instruction converter 10 will have two types of communication interfaces 103.

[0031] The instruction converter 10 includes an instruction conversion unit 100 as a function implemented by a computer program that operates the processor 104. In this embodiment, the instruction conversion unit 100 of the instruction converter 10 is implemented by an API (Application Interface) provided to the IT device 11. In this embodiment, the encryption service instruction that the IT device 11 sends to the instruction converter 10 is called the first encryption service instruction. The instruction conversion unit 100 of the instruction converter 10 has the function of sending a second encryption service instruction, which is the first encryption service instruction sent by the IT device 11, to the encryption device 12.

[0032] The instruction conversion device 10's storage 105 stores an instruction conversion table 101, which contains information on how to convert the encryption mechanism 120, as a data table used by the instruction conversion unit 100. The instruction conversion table 101 contains at least a description of the compromised encryption mechanism 120c and its alternative encryption mechanism 120d. When the instruction conversion unit 100 of the instruction conversion device 10 receives a first encryption service instruction from the IT device 11 that specifies at least an encryption mechanism 120, it checks whether the encryption mechanism 120 specified in the first encryption service instruction is described in the instruction conversion table 101 as a compromised encryption mechanism 120c. If the encryption mechanism 120 specified in the first encryption service instruction is a compromised encryption mechanism 120c, it sends a second encryption service instruction to the encryption device 12 that converts the encryption mechanism 120 specified in the first encryption service instruction to its alternative encryption mechanism 120d.

[0033] Figure 4 illustrates the instruction translation table 101 stored in storage 105. The instruction translation table 101 stored in storage 105 describes the translation rules for the cryptographic mechanism 120. As shown in Figure 4, the instruction translation table 101 includes a first field 101a that describes the compromised cryptographic mechanism 120c and a second field 101b that describes the alternative cryptographic mechanism 120d that corresponds to the compromised cryptographic mechanism 120c. In Figure 4, the name of the cryptographic mechanism 120 is listed as information that identifies the cryptographic mechanism 120, but the information that identifies the cryptographic mechanism 120 may also be a unique number for each cryptographic mechanism 120.

[0034] Figure 4 lists the following as vulnerable cryptographic mechanisms 120c: TDEA (Triple Data Encryption Algorithm), a symmetric-key cryptosystem; RSA2048, a public-key cryptosystem; and the SHA256hash hash function. According to Figure 4, the alternative cryptographic mechanism 120d for the symmetric-key cryptosystem TDEA is AES128, also a symmetric-key cryptosystem. The alternative cryptographic mechanism 120d for the public-key cryptosystem RSA2048 is ECDSA256, also a public-key cryptosystem. The alternative cryptographic mechanism 120d for the hash function SHA256 is SHA384, also a hash function. In the above descriptions, "256," "2048," and "384" refer to the number of bits.

[0035] Converting the compromised cryptographic mechanism 120c to the alternative cryptographic mechanism 120d also requires changing the cryptographic key used by the cryptographic mechanism 120. Therefore, the instruction conversion table 101 shown in Figure 4 includes a third field 101c that describes the conversion rules for the cryptographic key, in addition to the conversion rules for the cryptographic mechanism 120. In this embodiment, a unique key number is used for each cryptographic key to identify it. In Figure 4, the cryptographic key conversion rule is a conversion formula that converts the key number of the cryptographic key used by the compromised cryptographic mechanism 120c to the key number of the cryptographic key used by the corresponding alternative cryptographic mechanism 120d. Specifically, this conversion formula adds "1000" to the key number of the compromised cryptographic mechanism 120 to obtain the key number of the alternative cryptographic mechanism 120d.

[0036] Furthermore, depending on the user of the cryptographic device 12, it may be necessary to continue using the compromised cryptographic algorithm even if the algorithm is compromised. Therefore, the instruction translation table 101 shown in Figure 4 includes a fourth field 101d which describes exclusion conditions that indicate the conditions under which the compromised cryptographic mechanism 120c is not converted to the alternative cryptographic mechanism 120d. In Figure 4, the exclusion conditions are the values ​​of the exclusion flags to be included in the first cryptographic service instruction. In this embodiment, since the first cryptographic service instruction includes exclusion flags that the cryptographic device 12 does not use, the instruction translation unit sends the first cryptographic service instruction with the exclusion flags removed to the cryptographic device 12 if the value of the exclusion flags included in the first cryptographic service instruction matches the value of the exclusion flags described in the instruction translation table 101.

[0037] Figure 5 shows the syntax of the first cryptographic service instruction. The syntax of the first cryptographic service instruction is the same as the syntax of the second cryptographic service instruction, with the addition of exclusion flags. As shown in Figure 5, the syntax of the first cryptographic service instruction includes cryptographic service specification information, cryptographic mechanism specification information, and exclusion flags. If parameters are required, the syntax of the first cryptographic service instruction includes the parameters used by cryptographic mechanism 120. The first cryptographic service instruction can also include data to be processed by the cryptographic service or a pointer to pass this data. The cryptographic service specification information, cryptographic mechanism specification information, and parameters are the same as those of the second cryptographic service instruction, so a detailed explanation is omitted here.

[0038] In this embodiment, to prepare for situations where the compromised cryptographic mechanism 120 must be used even if the cryptographic mechanism 120 is compromised, the instruction translation table 101 shown in Figure 4 includes an exclusion condition that prevents the compromised cryptographic mechanism 120c from being translated. As a result, as shown in Figure 5, the syntax of the first cryptographic service instruction has the exclusion flag added. Note that if no exclusion condition is set in the instruction translation table 101, the syntax of the first cryptographic service instruction will be the same as that of the second cryptographic service instruction.

[0039] Figure 6 is a diagram illustrating the operation of the instruction conversion unit 100 of the instruction conversion device 10. The explanation of Figure 6 also serves to explain the instruction conversion method, which is the invention disclosed in this application.

[0040] The instruction conversion unit 100 of the instruction conversion device 10 receives a first cryptographic service instruction from the IT device 11 (step S1). The instruction conversion unit 100 of the instruction conversion device 10 checks whether the cryptographic mechanism 120 specified by the first cryptographic service instruction received from the IT device 11 is described in the instruction conversion table 101 as a compromised cryptographic mechanism 120c (step S2). Since the first field 101a of the instruction conversion table 101 describes the compromised cryptographic mechanism 120c, it is possible to determine whether the cryptographic mechanism 120 specified by the first cryptographic service instruction is a compromised cryptographic mechanism 120c by searching the first field 101a of the instruction conversion table 101 for the cryptographic mechanism 120 specified by the first cryptographic service instruction.

[0041] If the cryptographic mechanism 120 specified by the first cryptographic service instruction is not a compromised cryptographic mechanism 120c, that is, if the cryptographic mechanism 120 specified by the first cryptographic service instruction cannot be found in the first field 101a of the instruction translation table 101, the instruction translation unit 100 of the instruction translation device 10 proceeds to step S9 in Figure 6. In step S9 in Figure 6, the instruction translation unit 100 of the instruction translation device 10 removes the exclusion flag from the first cryptographic service instruction received in step S1 without changing the cryptographic mechanism 120, and sends the first cryptographic service instruction with the exclusion flag removed to the cryptographic device 12, thus ending the procedure in Figure 6.

[0042] If the cryptographic mechanism 120 specified by the first cryptographic service instruction is a compromised cryptographic mechanism 120c, that is, if the cryptographic mechanism 120 specified by the first cryptographic service instruction can be found in the first field 101a of the instruction translation table 101, the instruction translation unit 100 of the instruction translation device 10 proceeds to step S3 in Figure 6.

[0043] In step S3 of Figure 6, the instruction conversion unit 100 of the instruction conversion device 10 checks the exclusion flag included in the first cryptographic service instruction received from the IT device 11. The instruction conversion unit 100 of the instruction conversion device 10 refers to the fourth field 101d of the instruction conversion table 101, and if the value of the exclusion flag included in the first cryptographic service instruction matches the exclusion condition corresponding to the cryptographic mechanism 120 specified in the first cryptographic service instruction, the process proceeds to step S9 of Figure 6. In step S9 of Figure 6, the instruction conversion unit 100 of the instruction conversion device 10 removes the exclusion flag from the first cryptographic service instruction received in step S1 without converting the cryptographic mechanism 120, and sends the first cryptographic service instruction with the exclusion flag removed to the cryptographic device 12, thus ending the procedure in Figure 6.

[0044] If the value of the exclusion flag included in the first cryptographic service instruction does not conform to the exclusion conditions corresponding to the cryptographic mechanism 120 specified in the first cryptographic service instruction, the instruction conversion unit 100 of the instruction conversion device 10 proceeds to step S4 in Figure 6.

[0045] In step S4 of Figure 6, the instruction conversion unit 100 of the instruction conversion device 10 refers to the instruction conversion table 101 to identify an alternative cryptographic mechanism 120d corresponding to the cryptographic mechanism 120 specified in the first cryptographic service instruction received in step S1. This alternative cryptographic mechanism 120d is described in the second field 101b of the row in the instruction conversion table 101 that contains the cryptographic mechanism 120 specified in the first cryptographic service instruction.

[0046] Next, the instruction conversion unit 100 of the instruction conversion device 10 determines whether a conversion of the encryption key is necessary in conjunction with the conversion of the encryption mechanism 120 (step S5). To determine whether a conversion of the encryption key is necessary in conjunction with the conversion of the encryption mechanism 120, the third field 101c of the row in the instruction conversion table 101 that contains the encryption mechanism 120 specified in the first encryption service instruction is used. If no key number conversion expression is described in the third field 101c of the row containing the encryption mechanism 120 specified in the first encryption service instruction, the instruction conversion unit 100 of the instruction conversion device 10 determines that a conversion of the encryption key is unnecessary.

[0047] If it is determined that encryption key conversion is unnecessary, the instruction conversion unit 100 of the instruction conversion device 10 proceeds to step S6 in Figure 6, converts the encryption mechanism 120 specified in the first encryption service instruction to the corresponding alternative encryption mechanism 120d, and then sends a second encryption service instruction with the exclusion flag removed to the encryption device 12, thus ending the procedure in Figure 6.

[0048] If it determines that a conversion of the encryption key is necessary, the instruction conversion unit 100 of the instruction conversion device 10 proceeds to step S7 in Figure 6, and substitutes the key number included in the first encryption service instruction into the conversion formula described in the third field 101c of the row in which the encryption mechanism 120 specified in the first encryption service instruction is described, thereby converting the key number of the encryption key used by the encryption mechanism 120 specified in the first encryption service instruction to the key number of the encryption key used by its alternative encryption mechanism 120d. Next, the instruction conversion unit 100 of the instruction conversion device 10 converts the encryption mechanism 120 and the key number, and then sends a second encryption service instruction with the exclusion flag removed to the encryption device 12 (step S8), and the procedure in Figure 6 ends.

[0049] Figure 7 shows an example of the conversion of cryptographic service instructions. Based on Figure 4, the alternative cryptographic mechanism 120d for the symmetric key cryptography "TDEA" is the symmetric key cryptography "AES128". Therefore, in Figure 7, the cryptographic mechanism 120 "TDEA" specified in the first cryptographic service instruction requesting encryption is converted to "AES128" in the second cryptographic service instruction. The value of the key number (KID) used by "TDEA" is converted from "100" to "10100" based on the third field 101c of the line in which "TDEA" is listed. Also, based on Figure 4, the alternative cryptographic mechanism 120d for the public key cryptography "RSA2048" is the public key cryptography "ECDSA256". Therefore, in Figure 7, the cryptographic mechanism 120 "RSA2048" specified in the first cryptographic service instruction requesting decryption is converted to "ECDSA256" in the second cryptographic service instruction. The value of the key number (PKID) used by "RSA2048" is converted from "101" to "10101" based on the third field 101c of the line in which "RSA2048" is listed. Based on Figure 4, the alternative cryptographic mechanism 120d for the hash function "SHA256" is the hash function "SHA384". Therefore, in Figure 7, the cryptographic mechanism 120 "SHA256" specified in the first cryptographic service instruction requesting signature generation is converted to "SHA384" in the second cryptographic service instruction. Note that since hash functions do not use cryptographic keys, no key number conversion is performed. [Explanation of Symbols]

[0050] 1. Instruction Translation System 10 Instruction Converter 100 Instruction conversion unit 101 Instruction Conversion Table 102 RAM 103 Communication Interface 104 Processors 105 Storage 11 IT equipment 12 Cryptographic device 120 Cryptographic Mechanisms 120c Cryptographic Compromise Mechanism 120d Alternative Cryptographic Mechanisms

Claims

1. An instruction converter that relays communication between an encryption device that provides an encryption service using an encryption mechanism and an IT device that uses the said encryption service, An instruction translation table that describes at least a compromised cryptographic mechanism and an alternative cryptographic mechanism that replaces it, An instruction conversion unit, upon receiving a first cryptographic service instruction from the IT device that specifies at least one cryptographic mechanism, checks whether the cryptographic mechanism specified in the first cryptographic service instruction is described in the instruction conversion table as a compromised cryptographic mechanism, and if the cryptographic mechanism specified in the first cryptographic service instruction is a compromised cryptographic mechanism, converts the cryptographic mechanism specified in the first cryptographic service instruction to its alternative cryptographic mechanism, and transmits the second cryptographic service instruction converted to the alternative cryptographic mechanism to the cryptographic device. An instruction conversion device characterized by being equipped with the following features.

2. The instruction translation table contains a conversion formula that converts the key number of the encryption key used by the compromised encryption mechanism to the key number of the encryption key used by the alternative encryption mechanism, and the first encryption service instruction includes a key number that specifies the encryption key used in the encryption service. The instruction conversion unit converts the key number specified in the first cryptographic service instruction to the corresponding key number of the alternative cryptographic mechanism according to the conversion formula described in the instruction conversion table, and transmits the second cryptographic service instruction, in which the cryptographic mechanism and key number have been converted, to the cryptographic device. The instruction conversion device according to feature 1.

3. An exclusion condition indicating the conditions under which the compromised cryptographic mechanism is not converted to the alternative cryptographic mechanism is described in the instruction conversion table, and the first cryptographic service instruction includes an exclusion flag. The instruction conversion unit, if the value of the exclusion flag included in the first cryptographic service instruction matches the exclusion condition described in the instruction conversion table, sends the first cryptographic service instruction with the exclusion flag removed to the cryptographic device. An instruction conversion device as described in 1 or 2, characterized by the above.

4. The system includes an encryption device that provides an encryption service using an encryption mechanism, IT equipment that uses the encryption service, and an instruction converter that relays communication between the encryption device and the IT equipment. The aforementioned IT device is a device that transmits a first cryptographic service instruction specifying at least a cryptographic mechanism to the instruction converter, The instruction converter is, An instruction translation table that lists at least a compromised cryptographic mechanism and an alternative cryptographic mechanism that replaces it, The system includes an instruction conversion unit that, upon receiving the first encryption service instruction from the IT device, checks whether the encryption mechanism specified in the first encryption service instruction is described in the instruction conversion table as the compromised encryption mechanism, and if the encryption mechanism specified in the first encryption service instruction is the compromised encryption mechanism, transmits a second encryption service instruction to the encryption device, which converts the encryption mechanism specified in the first encryption service instruction to the alternative encryption mechanism. An instruction conversion system characterized by the following:

5. The instruction translation table contains a conversion formula that converts the key number of the encryption key used by the compromised encryption mechanism to the key number of the encryption key used by the alternative encryption mechanism, and the first encryption service instruction includes a key number that specifies the encryption key used in the encryption service. The instruction conversion unit converts the key number specified in the first cryptographic service instruction to the corresponding key number of the alternative cryptographic mechanism according to the conversion formula described in the instruction conversion table, and transmits the second cryptographic service instruction, in which the cryptographic mechanism and key number have been converted, to the cryptographic device. The instruction conversion system according to feature 4.

6. An exclusion condition indicating the conditions under which the compromised cryptographic mechanism is not converted to the alternative cryptographic mechanism is described in the instruction conversion table, and the first cryptographic service instruction includes an exclusion flag. The instruction conversion unit, if the value of the exclusion flag included in the first cryptographic service instruction matches the exclusion condition described in the instruction conversion table, sends the first cryptographic service instruction with the exclusion flag removed to the cryptographic device. The instruction conversion system according to claim 4 or 5, characterized by the features described above.

7. A method performed by an instruction converter that relays communication between an encryption device that provides an encryption service using an encryption mechanism and an IT device that uses the encryption service, When the instruction converter receives a first cryptographic service instruction from the IT device that specifies at least the cryptographic mechanism to be used in the cryptographic service, it performs a step a to check whether the cryptographic mechanism specified in the first cryptographic service instruction is described as the compromised cryptographic mechanism in the instruction converter table, which contains at least the compromised cryptographic mechanism and the alternative cryptographic mechanism that replaces it. If the cryptographic mechanism specified in the first cryptographic service instruction is the compromised cryptographic mechanism, step b is to send a second cryptographic service instruction to the cryptographic device, which converts the cryptographic mechanism specified in the first cryptographic service instruction to the alternative cryptographic mechanism therefor. A method for converting instructions, characterized by including the following:

8. The instruction conversion table contains a conversion formula that converts the key number of the encryption key used by the compromised encryption mechanism to the key number of the encryption key used by the alternative encryption mechanism, and the first encryption service instruction includes the key number of the encryption key used in the encryption service. In step b, the instruction converter converts the key number specified in the first cryptographic service instruction to the corresponding key number of the alternative cryptographic mechanism according to the conversion formula described in the instruction conversion table, and transmits the second cryptographic service instruction, in which the cryptographic mechanism and key number have been converted, to the cryptographic device. The instruction conversion method according to feature 7.

9. An exclusion condition indicating the conditions under which the compromised cryptographic mechanism is not converted to the alternative cryptographic mechanism is described in the instruction conversion table, and the first cryptographic service instruction includes an exclusion flag. In step b, if the value of the exclusion flag included in the first cryptographic service instruction matches the exclusion conditions described in the instruction conversion table, the instruction converter sends the first cryptographic service instruction with the exclusion flag removed to the cryptographic device. The instruction conversion method according to claim 7 or 8, characterized by the feature described above.

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