标准模型下的服务器辅助验证代理重签名方案

代理重签名具有转换签名的功能，在云存储、数据交换、跨域身份认证等领域有广泛的应用前景。目前大多数代理重签名方案需要复杂的双线性对运算，无法适用于计算能力较弱的低端计算设备。为了提高代理重签名的签名验证效率，该文给出了双向服务器辅助验证代理重签名的安全性定义，并提出一个高效的服务器辅助验证代理重签名方案，在标准模型下证明新方案在合谋攻击和选择消息攻击下是安全的。分析结果表明，新方案有效减少了双线性对的计算量，大大降低了签名验证算法的计算复杂度，在效率上优于已有的代理重签名方案。

Sever-aided Verification Proxy Re-signature Scheme in the Standard Model

Proxy re-signature has the function of converting signature, and has extensive application prospects, such as cloud storage, data exchange, cross-domain identity authentication and so on. However, most proxy re-signature schemes require expensive bilinear pairing operations, which are not suitable for low-power devices. To improve the performance of proxy re-signature schemes, the security model of a bidirectional sever-aided verification proxy re-signature is presented. Furthermore, a sever-aided verification proxy re-signature scheme is proposed. This scheme is proven to be secure under collusion attacks and adaptive chosen message attacks in the standard model. Analysis results show that the proposed scheme effectively reduces the computation cost of pairing operation, and it greatly reduces computational complexity of signature verification algorithm. The proposed scheme is more efficient than the existing proxy re-signature schemes.