The Improvement Of Cpk And The Design And Analysis Of Electronic Payment Protocols Based On Cpk

Electronic payment is an important application of cryptography in the area of commerce. As a key technology of electronic transaction, it has been studied extensively and achieves broad applications. As we know, strong identity authentication must be provided in the secure electronic payment protocols, which can be achieved by using asymmetric technologies of cryptography (public key technology) as the most improtant method. The realization of any end-to-end strong authentication in the super-large-scale area has to manage a large number of public keys. At present, there are only three methods to address this problem, PKI (Public key infrastructure), IBC (Identity-based cryptography) and CPK (combined public key cryptography) schemes. In fact, previous used electronic payment protocols are mostly based on PKI.At the same time, electronic payment sometimes has to provide off-line services, but traditional PKI scheme can not provide off-line query or public key authentication. So only the IBC and CPK schemes can satisfy the requirements. There have been some IBC-based electronic payment protocols. Regarding the CPK scheme of which our country owns the intellectual property rights, its security analysis and the study and application of CPK-based electronic payment protocols are much lacked.Based on the foundation project of information security industry base in Guangdong Province, this paper present the security analysis and the improvement of the CPK scheme, and some researches on CPK-based electronic payment protocols. The main work can be classified as follows:1. The basic CPK scheme and the CPK scheme including private key factors were introduced, and then their detailed security analyses and security holes were given and the improvement was also present. The improved scheme can prevent all the detected security holes, thus it can provide higher security.2. The SET (Secure Electronic Transaction) protocol was introduced, of which the advantages and disadvantages were given in this paper. Base on CPK, the improvement of the SET protocol was present, which is more efficient, simpler and safer than SET protocol.3. According to the requirement of the project, this paper designed an electronic payment system for micro-payment and gave the system structure and modular structure of the subsystem. A micro-payment protocol for on-line and off-line circumstances was present, whose security analysis and performance were also given.The innovation of this paper is that, the security holes of the CPK scheme including private key factors was pointed out, its improvement and security analysis of the improvement were given, and based on CPK, and the improvement of the SET protocol and a micro-payment protocol were respectively presented with formal security analyses.