ANONYMOUS SIGNATURE SYSTEM, SIGNATURE GENERATION DEVICE, ANONYMOUS SIGNATURE GENERATION DEVICE, VERIFICATION DEVICE, ANONYMOUS SIGNATURE METHOD, AND PROGRAM

摘要

To improve anonymity of anonymizable signatures.SOLUTION: An anonymous signature system includes setup means for generating an agent secret key w and a system parameter ρ with a safety parameter as an input, key generation means for generating a signer's private key x and public key y by using the system parameter ρ as an input, signature generation means for generating a signature r for a message m to be signed by using the secret key x and the message m as an input, anonymization means for generating a ring signature σ that anonymizes the signature r by using an identifier i of the signer, the agent secret key w, the signature r, a ring L indicating a group to which the signer belongs, a list yof a signer's public key y belonging to the ring L, and the message m as inputs, and verification means for outputting a verification result b of the message m by using the ring L, the list y, the message m, and the ring signature σ as inputs.SELECTED DRAWING: Figure 1