An efficient certificateless signature from pairings

A certificateless signature retains the efficiency of Shamir's identity-based signature while it does not suffer from the inherent private key escrow problem, which is first introduced by S. Al-Riyami and K. Paterson in Asiacrypt 2003. In this paper, we proposed a new certificateless signature scheme based on bilinear pairings. The proposed scheme is more efficient than those of previous schemes by pre-computing the pairing e(P, P) = g and publishing as the system parameters, it needs not to compute the pairing in the Sign stage, and only needs to compute three pairings in the Verify stage. In addition, the proposed scheme does not need the special MaptoPoint hash function and the confidential channel between KGC and users. The proposed scheme is unforgeable under the hardness assumption of the q-strong Diffie-Hellman problem and Computational Diffe-Hellman problem.