An Improved Proxy Multi-Signature, Multi-Proxy Signature and Multi-Proxy Multi-Signature Scheme

Abstract

Zhou’s proxy multi-signature scheme was a safe and effective scheme, but this scheme was not safety enough. In this work, security analysis was given to the scheme and results showed that the scheme was very easy aggressed by the forgery attack. The paper proposed that any attacker can sign some certain unauthorized messages after the attacker knows a valid signature, and any original signer ally with his proxy signer can forge any unauthorized messages. Then, the paper gave two kinds of inside attacks and outside attacks to the scheme correspondingly. Finally this paper proposed a new improved proxy multi-signature, multi-proxy signature and multi-proxy multi-signature schemes which based on the difficulty of the discrete logarithm problem (DLP). With verifying all the signers’ public keys, the improved schemes can resist lots of outsider attack and insider attack. The validity of the new scheme can be verified, and they are secure signature schemes.