基于区块链的无证书签密方案

签密算法能够在一个逻辑步骤中同时实现加密和签名功能，相较于传统的先签名后加密方案，签密算法具有计算量与通信成本低的优点，被广泛应用于电子支付、物联网等场景中。现有的基于椭圆曲线和双线性对实现的签密方案普遍存在执行效率低的问题，因此本文提出一种基于区块链的无证书签密方案。新方案基于离散对数实现，具有执行效率高等优点。新方案同时利用区块链不可篡改性和可追溯等优点，用以实现方案的不可否认性。安全性分析表明本文方案具有不可否认性、机密性及不可伪造等特性，性能分析表明新方案执行效率较高，仿真实验显示引入区块链后对系统整体性能影响甚微。

Certificateless Signcryption Scheme Based on Blockchain

Signcryption algorithm can realize encryption and signature functions at the same time in a logical step. Compared with the traditional scheme of signing first and then encrypting, signcryption algorithm has the advantages of low calculation amount and communication cost, and is widely used in electronic payment, Internet of Things, etc. Existing signcryption schemes based on elliptic curve and bilinear pairing generally have the problem of low execution efficiency. Therefore, this paper proposes a certificateless signcryption scheme based on blockchain. The new scheme is implemented based on discrete logarithm puzzle and has the advantages of high execution efficiency. The new scheme also takes advantage of the non-tamperable modification and traceability of the blockchain to achieve non-repudiation. Security analysis shows that the proposed scheme has the characteristics of non-repudiation, confidentiality, and unforgeability. Performance analysis shows that the new scheme is more efficient in execution. Simulation experiments show that the introduction of blockchain has little effect on the overall performance of the system.