Abstract:

The paper mainly analyses the YBX proxy signature scheme. An attacker can forge the proxy signature key without knowing the original signature＇s key and thus can forge the proxy signature. The scheme is based on the Chinese Remainder Theorem and the paper builds an enhanced proxy multiple signature s cheme based on an overall analysis of attacking schemes. It has two properties that the original signer can set up the time limit of the proxy power held by the proxy signer and can trace the receiver of the signature.

Key words: proxy signature, proxy multi-signature, discrete logarithm, Chinese Remainder Theorem