Chinese Journal of Computers   Full Text
Title	A Method to Construct a Class of Certificateless Signature Schemes
Authors	ZHANG Lei ZHANG Fu-Tai
Address	(College of Mathematics and Computer Science, Nanjing Normal University, Nanjing 210097)
Year	2009
Issue	No.5(940—945)
Abstract &   Background	Abstract Certificateless public key cryptography (CL-PKC) is a new paradigm in public key cryptography. It effectively solves the inherent key escrow problem in identity based public key cryptography (ID-PKC) while keeps its certificate free property. Designing efficient and secure signature schemes in certificateless public key setting is an interesting research topic that attracts the attentions of many researchers. This paper proposes a new method to construct a class of certificateless signature schemes. The schemes constructed using the new method can be proven secure in a very strong security model. The overall performances of the authors’ newly constructed schemes are better than that of the other certificateless signature schemes available in the literature. Keywords certificateless public key cryptography； computational Diffie-Hellman problem； bilinear pairing； certificateless signature； random oracle model Background This paper investigates efficient constructions of signature schemes in Certificateless public key setting. Digital signature is one of the most important primitives in public key cryptography. It provides authenticity, integrity and non-repudiation to many kinds of applications. In traditional public key cryptosystems, the management of certificates is usually complex and costly. Shamir introduced Identity-based public key cryptography to remove this requirement. However, key escrow problem is inherent in Identity-based public key cryptography. Certificateless public key cryptography is a new paradigm which was first introduced by Al-Riyami and Paterson in 2003. Their main purpose is to solve the key escrow problem in Identity-based public key cryptography, while keeping the implicit certification property of Identity-based public key cryptography. Recently, a number of certificateless signature schemes have been presented. The first one was presented by Al-Riyami and Paterson without formal security analysis. Later, Huang et al. pointed out a security drawback of this scheme and proposed a secure one. They also defined the security model of certificateless signature schemes. An improved security model was presented by Zhang et al. and an even stronger one was put forward by Hu et al. With respect to the efficiency, most of the previous secure CLS schemes involve a relatively large amount of paring computation and exponentiation in the process of signing and verification. In this paper, the authors show a new method to construct a class of certificateless signature schemes. This kind of schemes can be proven secure in a very strong security model. In addition, the constructed schemes have a better overall performance when compared with some other provably secure certificateless signature schemes available. The research is supported by the National Natural Science Foundation of China(No.60673070) and the Natural Science Foundation of Jiangsu Province(No.BK2006217). The projects focus on the study of secure and efficient encryption schemes, signature schemes and key agreement protocols in certificateless setting.