Certificateless Convertible Limited Verifier Signature Scheme

Certificateless public key cryptography (CL-PKC) as a new paradigm was introduced by Al-Riyami and Paterson in Asiacrypt 2003, which removes the use of certificate to ensure the authenticity of the user´s public key in the traditional certificate-based public key cryptography and also overcomes the key escrow problem in the identity-based public key cryptography. Motivated by the conflict between authenticity and privacy in the digital signature, the notion of limited verifier signature was introduced by Araki et al.. In this paper, to the best of our knowledge, we give the first precise definition and security notions for certificateless convertible limited verifier signature and then the first concrete signature scheme which is provably secure under the CDH assumption. We also extend our signature scheme into a certificateless convertible two limited verifiers scheme for certain applications at the end of this paper