关键词: 可验证环签名, 可验证代理环签名, 不可伪造性, 双线性对

Abstract: This paper points out that Li et al.’s two verifiable ring signature schemes do not satisfy the security property of unforgeability, i.e., any member in the ring can impersonate other members to generate the valid signature, and the real identity verification algorithm shows that the real identity of the signature is the latter. In order to remedy the aforementioned security defects of the two verifiable ring signatures chemes, this paper puts forward two improved schemes. The improved schemes combine the real identity verification algorithm with the signer’s private key, public key and the signature such that the attacker cannot forge valid signature of other signer without knowing the private key of the signer, and enhancing the security property of the original schemes.

Key words: verifiable ring signature, verifiable proxy ring signature, unforgeability, bilinear pairings