An efficient certificateless proxy signature scheme without pairing

The proxy signature scheme allows a proxy signer to sign messages on behalf of an original signer, a company or an organization. Such schemes have lots of practical applications, particularly in distributed computing, where delegation of rights is quite common. Recently, the certificateless public key cryptography has attracted much attention since it could solve the certificate management problem in the traditional public cryptography and the key escrow problem in the identity-based cryptography. Many certificateless proxy signature schemes using pairing have been proposed. The pairing operation is a very complicated operation. So the performance of these schemes is not very good. In this paper, we propose the first certificateless proxy signature scheme without pairing. We argue that due to significant reduction in costs of computation and storage, our scheme is particularly suitable for practical applications with severely constrained resources. We also show our scheme is secure against both of the super Type I and the super Type II adversaries.