Certificateless Signature Scheme Based on Rabin Algorithm and Discrete Logarithm

Certificateless signature is one of the most important security primitives which can be used to solve the key escrow problem existing in ID-based signature. The security of most certificateless signatures depends only based on one mathematical hard problem. This means that once the underlying hard problem is broken, the signature will be broken, too. In this paper, a certificateless signature whose security depends on two mathematical hard problems, discrete logarithm and factoring problems, is proposed. Our scheme can be proved to be secure in the random oracle. Only both of the discrete logarithm and factoring problems are solved can our signature be broken. On the other hand, compared with the other schemes of this kind, our scheme is more efficient. Especially, in our scheme, it is very efficient to sign a signature, since there is not any exponential modular computation when the precomputation is ignored. Then, compared with the other schemes of this kind, our scheme has a better security and efficiency.