Generic Construction of Certificateless Signature

To provide the binding between a user and his public key, traditional digital signature schemes use certificates that are signed by a trusted third party. While Shamir’s identity-based signature scheme can dispense with certificates, the key escrow of a user’s private key is inherent in the identity-based signature scheme. In Asiacrypt 2003, a new digital signature paradigm called the certificateless signature was introduced. The certificateless signature eliminates the need for certificates and does not suffer from the inherent key escrow problem. In this paper, we provide a generic secure construction of a certificateless signature. We also present an extended construction whose trust level is the same as that of a traditional public key signature scheme.