一个改进的代理盲签名方案

Improved proxy blind signature scheme

通过对代理盲签名方案的分析,指出该方案不具有不可追踪性,攻击者可以原始签名者的身份再次发布代理公钥,代理授权阶段传输信道必须是安全信道,且原始签名者可以伪造代理签名者的盲签名等安全缺陷。针对这些安全缺陷,提出了一个新的代理盲签名方案,新的方案具有不可追踪性的特点,解决了攻击者再次发布代理公钥,代理签名者盲签名被伪造等问题,而且信息在非安全信道中仍可以安全传输,新的方案具有更高的安全性和实用性。新的方案可应用到电子现金等现实领域中,并给出了一个电子现金方案。

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.