Study On ID-based Cryptosystem And Its Applications

Information security is one of the most important problems in modern information society. It plays a very important role in the information science. Encryption technology can protect the information and data's confidentiality. Digital signature technology, which can realize the authentication, integrity and non-repudiation, is one of the key techniques of information security. They have been widely used in E-commerce and E-governance and so on.In this dissertation, we mainly study identity-based (simply ID-based) encryption, ID-based signature and group signature. The main results are as follows:(1) An overview and introduction to the basic concept and principle of public key cryptography and digital signature is provided, including their research history, recent studies and the direction. A summary of their applications in information security is given.(2) A brief description of some basic schemes of public key encryption and digital signature is presented. The development of ID-based cryptosystem is introduced, and two kinds of public key cryptosystem, ID-based and certificate-based, are compared. And we give the analogy and the difference of the two systems.(3) A detailed introduction and analysis of an ID-based encryption scheme is provided. With some simple variations of the scheme, multi-PKG system and multi-ID system is proposed, and we discuss the applications.(4) The basic construction of ID-based signature is summarized. We introduce an ID-based signature scheme from bilinear pairings and discuss its efficiency. An overview and introduction to group signature is presented, including its basic concept, property and development. We also present a general method to construct discrete-logarithm-based group signature scheme. Based on ID-based signature scheme, we propose an ID-based group signature scheme. We also discuss the security and efficiency of the proposed scheme.