标准模型下增强的基于身份部分盲签名

Extended Identity-based Partially Blind Signature Scheme in the Standard Model

标准模型(无随机预言)将密码算法规约为求解困难数学问题。研究了一种标准模型下的身份部分盲签名,指出其不能防止签名请求者篡改公共信息。提出一种增强的身份部分盲签名机制,从两方面改进了原有方案:一方面,采用隐式签名防止参与者篡改公共信息;另一方面,去除了额外的附加协议。参照Paterson等的标准签名模型,定义了部分盲签名的标准安全模型。增强方案在标准模型下被规约为求解椭圆曲线上的CDH(computational Diffie-Hellman)难题,被证明满足不可伪造性和部分盲性。对比分析表明,新方案在增强安全性的同时具有更低的计算开销和算法开销,可用于构建安全的电子现金或电子投票等协议。

Cryptography algorithm can be reduced to solve difficult mathematical problems in the standard model （without random oracle assumption）. In order t6 overcome the problem that in the standard model, an existed identity-based partially blind signature （IBPBS） scheme does not prevent a tampering, an enhanced IBPBS scheme was put forward. The original algorithm was improved by the en- hanced scheme in two ways. One was to adopt an implicit signature which effectively prevented the entities who were involved in the signature tampering the public information. The other was to avoid using additional supplementary protocols. Based on the standard model of signature mentioned by Paterson et al, a standard model of IBPBS was defined. The enhanced IBPBS scheme was reduced to resolve the CDH problem on an elliptic curve in the standard model, and was proved to achieve the unforgeability and the unlinkability. Comparative analysis showed that the new IBPBS scheme wins enhanced security, lower computational overhead and lower algorithm o- verhead, and can be used to build secure protocols on electronic cash or electronic voting as well.