Partial disposable signature system and method, signature device, verification device and program

摘要

PROBLEM TO BE SOLVED: To provide a signature technique more efficient than the conventional one.SOLUTION: Reference character pk=(h,h) denotes a stationary verification key that can be used for multiple times of signature and verification, and reference character sk=(h) denotes a stationary signature key that can be used for multiple times of signature and verification. A throwaway key generation device 2 sets ma prescribed value to generate a random value r, calculates z=h(m,r), and thereby generates a throwaway verification key opk=(z) and a throwaway signature key osk=(r). A signature device 3 generates a random number r' using the signature key sk=(h) and the throwaway signature key osk=(r), M being a signature object message, calculates r'=h(m,r,h(M,r')), and thereby generates a signature &sgr;=(r',r'). A verification device 4 verifies whether zaccords with h(h(M,r'),r') using the verification key pk=(h,h), the throwaway verification key opk=(z), the message M, and the signature &sgr;=(r',r').