INDEX CALCULATION SYSTEM, INDEX CALCULATION METHOD, INDEX CALCULATION PROGRAM, AND VERIFICATION SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide an index calculation system, etc., with which it is possible to calculate an index that makes a safer verification process possible.SOLUTION: An index calculation system 901 has: a first index calculation unit 902 for creating, on the basis of a cryptographic key and a numerical value included in a first number sequence, an encrypted first number sequence that includes an encrypted numerical value in which a numerical value included in the first number sequence is encrypted using the cryptographic key, storing the created encrypted first number sequence in a storage unit 904, and calculating an encrypted first index that represents an encrypted value in which a first size representing the magnitude of the first number sequence is encrypted using the cryptographic key; and a second index calculation unit 903 for calculating, on the basis of the encrypted numerical value included in the encrypted first number sequence stored in the storage unit 904 and a second number sequence, an encrypted second index in which a second index representing a value derived by subtracting the first size from a value representing the degree of similarity of the first number sequence and second number sequence represents a value encrypted using the cryptographic key.SELECTED DRAWING: Figure 20