Abstract: By analyzing the certificateless verifiable ring signature scheme (LUO DAWEN, HE MINGXING, LI XIAO. Certificateless verifiable ring signature scheme. Computer Engineering,2009, 35(15): 135-137) and the verifiable proxy ring signature scheme (LUO DAWEN, HE MINGXING, LI XIAO.A verifiable proxy ring signature scheme.Journal of Southwest University for Nationalities:Natural Science Edition, 2009, 35(3):608-611), it was found that these convertible ring signature schemes were susceptible to non-repudiation attack, i.e., any member in the ring can impersonate others identity to sign the message and the verifier believed the signature was signed by the latter. To address the above problems, improved schemes were proposed by using the private key of the signer to have a secret value. The security analysis proves that the improved schemes overcome the security defect of the original scheme and satisfy all security requirements of verifiable ring signature.

Key words: ring signature, verifiable ring signature, bilinear pairings, non-repudiation, anonymity

摘要： 通过对罗大文等提出的无证书的可验证环签名方案(罗大文, 何明星, 李虓. 无证书的可验证环签名方案. 计算机工程, 2009, 35(15): 135-137)和可验证的代理环签名方案(罗大文, 何明星, 李虓.可验证的代理环签名方案. 西南民族大学学报:自然科学版, 2009, 35(3):608-611)进行分析，指出这两个可验证环签名方案不满足不可否认性，即环中的成员可以冒充环内其他成员生成有效的环签名，并使验证者相信签名是后者所为。针对上述问题，利用签名者的私钥产生秘密值，提出了改进的可验证环签名方案，安全性分析表明改进的方案克服了原方案的安全缺陷，满足可验证环签名的所有安全要求。

关键词: 环签名, 可验证环签名, 双线性对, 不可否认性, 匿名性