Signature verification system, signature verification method, and storage medium

1. A signature verification system for verifying a signature by a computer comprising a processor and a memory, the signature verification system comprising:

a biometric information acquiring unit for acquiring biometric information of a user;

a public template certificate generating unit for generating a public template certificate by applying predetermined processing to the biometric information;

a key pair generating unit for generating a pair of a secret key and a public key;

a public key certificate generating unit for generating a public key certificate by attaching a biometric signature to the public key using the biometric information as a key; and

a verifying unit for accepting a transaction including the public template certificate, the public key certificate, and the signature, verifying validity of the public key certificate with the public template certificate, and verifying the signature with the public key certificate.

2. The signature verification system according to claim 1 ,

wherein the transaction includes a public key certificate of a transaction source and a public template certificate of a transaction destination, and

the verifying unit accepts a first transaction and a second transaction subsequent thereto, verifies a public key certificate of the second transaction by using a public template certificate of the first transaction, and verifies a signature included in the second transaction by using the public key certificate included in the second transaction.

3. The signature verification system according to claim 1 , further comprising:

a public template certificate storing unit for storing the public template certificate in association with a first identifier,

wherein the transaction stores the first identifier in place of the public template certificate, and

the verifying unit acquires the first identifier of the transaction to acquire the public template certificate associated with the first identifier from the public template certificate storing unit.

4. The signature verification system according to claim 1 ,

wherein the public template certificate of the transaction includes a signature value generated with a secret key of a certificate authority, and

the verifying unit verifies the signature value of the public template certificate using a public key of the certificate authority.

5. The signature verification system according to claim 1 ,

wherein the public template certificate of the transaction includes a signature value having biometric information as a key and a public template generated from the biometric information, and

the verifying unit acquires the public template from the transaction and verifies the signature value of the public template certificate by using the public template.

6. The signature verification system according to claim 1 , further comprising:

a public key revocation application form generating unit for issuing a public key revocation application form attached with a second identifier for identifying the public key certificate and a biometric signature using the biometric information as a key.

7. The signature verification system according to claim 6 ,

wherein the public key certificate generating unit acquires a public template certificate associated with the issued public key revocation application form, acquires biometric information of a user who uses the public template certificate, and in a case where the biometric information used for generation of the public template certificate matches with the acquired biometric information, generates a new key pair and a new public key certificate.

8. The signature verification system according to claim 1 ,

wherein the computer comprises: a registration terminal for generating a key pair and a public key certificate; a verification terminal for accepting and verifying a transaction; and a public template repository for generating a public template certificate,

the registration terminal comprises the biometric information acquiring unit, the key pair generating unit, and the public key certificate generating unit,

the verification terminal comprises the verifying unit, and

the public template repository comprises the public template certificate generating unit.

9. A signature verification method for verifying a signature by a computer comprising a processor and a memory, the signature verification method comprising:

a first step of acquiring biometric information of a user by the computer;

a second step of generating a public template certificate by applying predetermined processing to the biometric information by the computer;

a third step of generating a pair of a secret key and a public key by the computer;

a fourth step of generating a public key certificate by attaching a biometric signature to the public key using the biometric information as a key by the computer;

a fifth step of accepting a transaction including the public template certificate, the public key certificate, and the signature by the computer; and

a sixth step of verifying validity of the public key certificate with the public template certificate included in the transaction and verifying the signature with the public key certificate by the computer.

10. The signature verification method according to claim 9 ,

wherein the transaction includes a public key certificate of a transaction source and a public template certificate of a transaction destination, and

the fifth step includes accepting a first transaction and a second transaction subsequent thereto, and

the sixth step includes verifying a public key certificate of the second transaction by using a public template certificate of the first transaction and verifying a signature included in the second transaction by using the public key certificate included in the second transaction.

11. The signature verification method according to claim 9 ,

wherein the second step includes storing, in a public template certificate storing unit, the public template certificate in association with a first identifier,

the transaction stores the first identifier in place of the public template certificate, and

the sixth step includes acquiring the first identifier of the transaction to acquire the public template certificate associated with the first identifier from the public template certificate storing unit.

12. The signature verification method according to claim 9 ,

wherein the public template certificate of the transaction includes a signature value generated with a secret key of a certificate authority, and

the sixth step includes verifying the signature value of the public template certificate using a public key of the certificate authority.

13. The signature verification method according to claim 9 ,

wherein the public template certificate of the transaction includes a signature value having biometric information as a key and a public template generated from the biometric information, and

the sixth step includes acquiring the public template from the transaction and verifying the signature value of the public template certificate by using the public template.

14. The signature verification method according to claim 9 , further comprising:

a seventh step of issuing, by the computer, a public key revocation application form attached with a second identifier for identifying the public key certificate and a biometric signature using the biometric information as a key.

15. A non-transitory computer-readable recording medium storing a program for controlling a computer having a processor and a memory, the program causing the computer to execute:

a first step of acquiring a message to be included in a transaction;

a second step of generating a hash value of information included in the transaction;

a third step of attaching a signature by using a secret key having been generated in advance for the hash value;

a fourth step of acquiring a public template certificate having been generated in advance by applying predetermined processing to biometric information;

a fifth step of acquiring a public key certificate obtained by attaching a biometric signature to a public key corresponding to the secret key by using the biometric information as a key; and

a sixth step of generating the transaction including the public template certificate, the public key certificate, the message, and the signature.