Improvement of a New Proxy Signature Scheme
一种新型的代理签名方案的改进

In this paper, a new anonymous proxy signature scheme proposed by Gu Li-ze et al.(2005) is cryptanalyzed in detail and is proved that this scheme is not secure against the original signer’s forgery attack and then four methods to attack the new scheme are found. To avoid these attacks, the new scheme is revised and two improved schemes are given. Finally, the improved schemes are concluded that they are both secure against the original signer’s forgery attack.