Improved proxy blind signature scheme
一个改进的代理盲签名方案

In this paper, we analyzed the proxy blind signature scheme proposed by Lal and Awasthi. We pointed out the insecurity of the L-A scheme. It is of the untraceability property. An adversary can republish the proxy public key and claim that he is the original signer. It needs a secure channel in the L-A scheme, and the original signer can forge the blind signature of the proxy signer. Then we proposed a new proxy blind signature scheme to overcome the pointed out drawback in L-A scheme. We proved that the new scheme is more secure and useful. As an instance, application of the new scheme in electronic cash was described.