SECRET EQUALITY DETERMINATION SYSTEM, SECRET EQUALITY DETERMINATION METHOD AND SECRET EQUALITY DETERMINATION PROGRAM RECORDING MEDIUM

摘要

Defining L as the bit length of the order of a ring, this secret equality determination system runs while suppressing the number of communication rounds to O(Log_(L)), regardless of the secret sharing scheme. This secret equality determination system is provided with a random number generation server device, a mask value restoration server device, and a secret calculation server device. The random number generation server device is provided with a random number generation unit which generates random numbers, a share addition unit which generates secret sharing data masked using random numbers and the secret sharing data of operands in the secret equality determination, a secret sharing data generation unit which generates secret sharing data of inputted values, a secret sharing data restoration unit which obtains the original values by restoring the secret sharing data, and a determination bit-conjunction unit which uses the secret sharing data to perform a secret equality determination. The mask value restoration server device is provided with a secret sharing data generation unit which generates secret sharing data of inputted values, a secret sharing data restoration unit which obtains the original values by restoring the secret sharing data, and a determination bit-conjunction unit which uses the secret sharing data to perform a secret equality determination. The secret calculation server device is provided with a secret sharing data generation unit which generates secret sharing data of inputted values, a secret sharing data restoration unit which obtains the original values by restoring the secret sharing data, and a determination bit-conjunction unit which uses the secret sharing data to perform a secret equality determination.