On the Security of ID-Based One-Off Blind Public Key

ID-based cryptography is an important cryptographic system. Recently, by combining RSA and Fiat-Shamir identity authentication scheme, an ID-based one-off Blind public key was proposed to protect user´s privacy in, and the authors claimed that the scheme had anonymity and unforgeability. In this paper, we give security analysis to the scheme of, and show this scheme has linkability and universal forgery. We make two signatures which were produced by an individual constitute a relation and any user can forge a signature on arbitrary message without being tracing by the trust center.