Efficient certificateless signature schemes

Abstract

Recently, in order to eliminate the use of certificates in certified public key cryptography and the key-escrow problem in identity based cryptography, the notion of certificateless public key cryptography was introduced. In this paper, to construct an efficient certificateless signature (CLS) scheme, we present a new approach compactly and orthogonally combining short signatures using bilinear maps. Our approach is conceptually simple but effective to improve efficiency greatly. In the proposed CLS scheme a full private key of a user is a single group element and signature verification requires only one pairing operation. In addition, our CLS scheme has a flexible structure which can be easily extended to a certificateless signature scheme with additional properties such as certificateless ring and blind signature schemes. © Springer-Verlag Berlin Heidelberg 2007.