The Signature Algorithm Based On Automata Theory, While Research And Realization

Electronic Commerce is the Internet-Based exchange of tangible merchandize or intangible service between two or more parties, the fair exchange protocol have been widely used in electronic commerce. Concurrent signature is designed to resolve the fair exchange problem of digital signature, which was proposed by Chen et al. in 2004.Two Chinese cryptographers Tao Renji and Chen Shihua introduced the Finite Automata Public Key Cryptosystem (FAPKC), which is based on the invertibility theory of finite utoma. It is the first time-sequence public key cryptosystem. Compared with other popular public key systems, FAPKC is easy to be implemented and is more efficient because it only uses logical operations.This paper chiefly refers to the following works:1. Summarizes the research on Concurrent Signature in recent years. Introduces Concurrent Signature Scheme, Perfect Concurrent Signature Scheme, Multi-Party Concurrent Signature Scheme, and analyzes the security of these schemes.2. Proposes a concrete Perfect Concurrent Signature scheme based on FAPKC. Defines the security model and introduces the notion of Perfect Ambiguity and Perfect Fairness. Proves that FAPCS scheme satisfies the security model.3. Implements the FAPCS scheme using C++ language. Defines the basic data structure, the core algorithms, gives out a concrete demo to illustrate the FAPCS protocol and the calling sequence of the core algorithms.At last, some open questions and future work are discussed.