基于SM9算法可证明安全的区块链隐私保护方案

为了解决区块链交易过程中的隐私泄漏问题，对SM9标识密码算法进行改进，提出了基于身份认证的多KGC群签名方案.以联盟链为基础，设计了基于SM9算法可证明安全的区块链隐私保护方案，并对以上方案进行安全性与效率分析.通过分析证明，方案具有签名不可伪造、保证节点匿名及前向安全等特性.通过效率分析：该方案较Al-Riyami等人提出的无证书签名方案减少2次双线性对运算，验签效率提高约40%；较Tseng等人与Chen等人提出的方案分别减少4次与2次指数运算，计算效率整体得到提高.该方案通过多KGC群签名保护交易双方的用户身份，实现在节点间进行身份验证的同时，保护了节点的隐私.

Privacy Preserving Scheme in Block Chain with Provably Secure Based on SM9 Algorithm

In order to solve the problem of privacy leakage in the transaction process of block chain, by improving the SM9 identification cryptography algorithm, a multi KGC group signature scheme based on SM9 algorithm was proposed for the first time. Based on the alliance chain, a privacy preserving scheme in block chain with provably secure was designed based on SM9 algorithm. By analyzing the security and efficiency about this scheme, it is proved that the proposed scheme has many advantages, such as signature unforgery, the node anonymity, forward security, and so on. By analyzing the efficiency, the proposed scheme decreases twice bilinear pairing operations compared with the certificateless signature scheme proposed by Al-Riyami S Ss'', and the efficiency of signature verifying is increased by about 40%. Moreover, the proposed scheme cuts down four times and twice exponent operations compared with schemes of Tseng Y Ms'' and Chen Ys'', the overall calculation efficiency is improved. The user identity of two parties can be protected by the cryptographic operation, and the privacy preserving of the nodes is achieved.