关键词: 代理盲签名, 离散对数, 非关联性, 伪造攻击

Abstract: Through?the security analysis of?the proxy blind signature scheme which is proposed by Liu et al., it shows that security flaws exist in the scheme: a dishonest original signer can forge the proxy signing key, that is to say it doesn’t satisfy strong unforgeability; the proxy signer can make a linkage between the signature on original message and the signature on corresponding blind message, that is to say the scheme is linkable. An improved scheme is proposed to overcome these security problems. By modifying the?equation of?the delegate authorization and the process of blind signature, the new scheme can resist the original signer’s forgery attacks, and also has unlinkability.

Key words: proxy blind signature, discrete logarithm, unlinkability, forgery attack