Certificateless Multi-Signature Based on SM2 Algorithm and Its Application in Blockchain Transaction

Multi-signature is widely used in blockchain transaction schemes. Despite increasing demand for the localization of blockchain applications, research on multi-signature has not sufficiently focused on secure and efficient SM2 algorithms. Additionally, most existing solutions rely on the Public Key Infrastructure (PKI) system to implement certificate management, which poses efficiency and scalability issues. Therefore, this study proposes a certificateless multi-signature scheme based on the SM2 algorithm. First, in the SM2 key generation stage, a certificateless cryptographic mechanism is introduced to avoid expensive certificate management, and a key holding proof is designed to resist malicious key attacks. Second, by introducing a tree structure, an "online-offline" SM2 multi-signature algorithm is designed to achieve efficient and highly scalable signature generation. The scheme is proven to satisfy the Existential UnForgeability under Chosen Message Attacks (EUF-CMA) in a Random Oracle Model (ROM). Finally, the proposed solution is applied to the Hyperledger Fabric consortium chain to optimize the blockchain transaction process. Results of a performance analysis show that, compared with existing signature schemes, the proposed scheme is more effective in reducing computational and communication overhead while ensuring security.