COMMITMENT SYSTEM, COMMON REFERENCE INFORMATION GENERATION DEVICE, COMMITMENT GENERATION DEVICE, COMMITMENT RECEIVING DEVICE, AND COMMITMENT METHOD

摘要

PROBLEM TO BE SOLVED: To provide a method for composing a commitment capable of CRS reusable, non-interactive and information discarding non-required type general purpose coupling.SOLUTION: A commitment system of the present invention comprises a common reference information generation device, a commitment generation device, and a commitment receiving device. Further, the commitment system utilizes a key generation algorithm and an encryption algorithm of ABM cipher which satisfy four safety conditions necessary to make non-interactive, CRS reusable and information discarding non-required general purpose coupling possible. The common reference information generation device generates a public key according to the key generation algorithm of ABM cipher and publishes it as common reference information. The commitment generation device encrypts plaintext according to the encryption algorithm of ABM cipher to generate a commitment. The commitment receiving device checks according to the encryption algorithm of ABM cipher whether a received commitment is the one encrypted from received plaintext.