Pairing-free certificateless signature with revocation

How to revoke a user is an important problem in public key cryptosystems. Free of key escrow and costly certificate management, the certificateless public key cryptosystem (CLPKC) is advantageous over both the identity-based public key system and the traditional public key system . However, there are few solutions to the revocation problem in CLPKC. In this paper, we present an efficient revocable certificateless signature scheme. This new scheme can revoke a user with high efficiency. We also give a method to improve the scheme to be signing-key-exposure-resilient. Based on the discrete logarithm problem, our scheme is provably secure.