Abstract: Linkable ring signatures not only inherit the advantages of ring signatures, but also embed link tags in the signature scheme, enabling verifiers to determine whether two signatures are generated by the same signer, which effectively addresses the issues of abuse or repeated signatures. The Certificateless Public Key Cryptography （CL-PKC） mechanism can resolve the problems of key escrow and certificate management, thereby enhancing security. By combining the advantages of the above two, a CertificateLess Linkable Ring Signature scheme (CL-LRS) based on elliptic curves was proposed. The system model and security model of the scheme were constructed, and it was proven in the random oracle model that the scheme can resist Type I/II adversary attacks with anonymity, unforgeability, linkability, and non-slanderability. To verify the practical performance of the propsed scheme, the signature overhead and verification overhead of the proposed scheme were compared with those of several existing elliptic-curve-based ring signature schemes by calculating the time of each cryptographic operation used in the signature scheme. The experiments indicate that without relying on bilinear pairing operations, the propsed scheme can still resist attacks from malicious key generation centers and prevent potential signature abuse. Meanwhile, the total signature time is reduced by 80.1% compared with the elliptic-curve-based linkable ring signature. Therefore it is suitable for applications in resource-constrained scenarios.

Key words: linkable ring signature, certificateless encryption, random oracle model, anonymity, unforgeability

摘要： 可链接环签名不仅继承了环签名的优势，且在签名方案中嵌入链接标签使验证者可以确定2个签名是否由同一签名者生成，从而解决了滥用或重复签名的问题；无证书公钥密码（CL-PKC）体制可解决密钥托管问题以及证书管理问题从而提高了安全性。结合上述两者的优点，提出一种基于椭圆曲线的无证书可链接环签名方案(CL-LRS)，构建方案的系统模型和安全模型，并在随机预言机模型下证明方案能抵抗I/II型敌手攻击，具备匿名性、不可伪造性、可链接性和不可诽谤性。为验证方案的实际性能，通过计算签名方案中使用的各密码运算的时间对所提方案与现有的几种基于椭圆曲线的环签名方案的签名开销和验签开销进行对比分析。实验结果表明，在不依赖双线性配对运算的情况下，所提方案仍然能抵抗恶意密钥生成中心攻击且能防范潜在的签名滥用行为，同时在签名总耗时上与基于椭圆曲线的可链接环签名相比减少了80.1%，因此适合于资源受限场景下的应用。

关键词: 可链接环签名, 无证书加密, 随机预言机模型, 匿名性, 不可伪造性