摘要： 为了解决现有国密SM9盲签名方案中签名私钥易泄露以及签名权力过于集中的问题，提出一种基于国密SM9的两方协同盲签名方案。密钥生成中心将SM9的签名私钥分割成两个部分并分配给两方签名者，同时设计一种两方协同盲签名的协议，在该协议中用户使用特定的盲化因子对待签消息进行盲化，由两个签名参与方合作生成合法的SM9盲签名。该协议保证只有拥有签名权限的通信双方才能合作生成有效的SM9盲签名，且在交互签名的过程中不会泄漏完整的SM9签名私钥，在保护待签消息隐私的同时能有效解决现有SM9盲签名中签名私钥的安全性问题，且两方签名协议的设计能满足特定场景下对分散签名权力的需求。理论分析与仿真结果表明，该方案的签名长度接近现有SM9相关签名方案但功能更加完善，在通用安全构架下被证明满足盲签名的基本安全要求，相较原始SM9签名方案，所提方案在增加合理时间消耗的前提下能够有效提高协同特性。

关键词: SM9算法, 基于标识的签名, 盲签名, 密钥分割, 两方协同签名

Abstract: In the existing SM9 blind signature scheme，the signature private key is leaked easily and the signature power is centralized，which are problematic.Hence，a two-party collaborative blind signature scheme based on SM9 is proposed.The Key Generation Center（KGC） separates the signature private key of SM9 into two and distributes it to two signers.Additionally，it designs a two-party cooperative blind signature protocol，in which the user uses a specific blinding factor to conceal the message to be signed，and the two signature participants cooperate to generate a legal SM9 blind signature.This protocol ensures that only the communication parties with signature authority can cooperate to generate an effective SM9 blind signature and that the complete SM9 signature private key will not be disclosed during an interactive signature.Thus，the security problem of the signature private key in the existing SM9 blind signature is solved effectively while the privacy of the message to be signed is protected.Furthermore，the design of the two-party signature protocol satisfies the requirements for decentralized signature authority in specific scenarios.Theoretical analysis and simulation results show that the signature length of the proposed scheme is similar to that of the existing SM9-related signature scheme but its function is more ideal；additionally，the proposed scheme can satisfy the basic security requirements of blind signatures under the general security framework.Compared with the original SM9 signature scheme，the proposed scheme can effectively improve its cooperative characteristics by increasing the reasonable time consumption.

Key words: SM9 algorithm, Identity-Based Signature（IBS）, blind signature, key segmentation, two-party cooperative signature

中图分类号: 

• TP391