A Provably Secure Certificateless User Authentication Protocol for Mobile Client-Server Environment

Based on mobile devices limitations, several user authentications and key exchange schemes have been proposed for mobile devices using identity-based public key cryptography (ID-PKC). However, these schemes suffer from key escrow problem. Moreover, they are not secure against impersonation attacks, and they can’t achieve perfect forward secrecy. In this paper, a new user authentication and key exchange protocol for the mobile client-server environment is proposed. Certificateless public key cryptography (CL-PKC) and bilinear pairing are adopted in the proposed scheme. Our protocol solves the key escrow problem of identity-based public key cryptography. Also, it is secure against both adversaries type I and type II. Furthermore, the proposed protocol achieves perfect forward secrecy. We prove the security of our protocol in the random oracle model under the Computational Diffie-Hellman (CDH) problem. Hence, the proposed scheme is more suitable for the mobile devices environments.