Abstract:

The existing identity-based proxy signature schemes are secure in the random oracle model but not al- ways secure in the real world. In order to solve this problem, a security model of identity-based proxy signature schemes is presented, and a new identity-based proxy signature scheme is proposed. The security of the proposed scheme is then proved based on the computational Diffie-Hellman assumption without using the random oracle heu- ristic in the presented security model. The results indicate that, as compared with the efficient identity-based proxy signature scheme recently presented, the proposed scheme only needs an additional bilinear mapping.

Key words: signature, proxy, random oracle model, bilinear mapping, computational Diffie-Hellman assumption