As the fast growing of the global E-commerce, the research of the network security and network technology is more challenging. In this paper, the critical technology of E-commerce's security and broadband MAN is studied extensively.First of all, on the basis of the analysis of the E-commerce security mechanism and security deal protocol, an improved SET protocol based on the combined cryptographic algorithms is proposed. Aimed to the limit of cryptographic algorithms in SET protocol, the methods of creation and authentication of combined algorithms digital certificate and digital signature are given to improve the adaptability and security.Secondly, the existing models and application of electronic cash are analyzed. And a novel Brand's of electronic cash scheme based on probabilistic verification is proposed. The security of electronic cash is improved by adding the integrated calculation of the credit of the user and the busyness of LOC.Thirdly, a novel intelligent firewall architecture is proposed on the basis of the classical schemes. And a novel integrated VPN architecture is proposed by comparing IPSec VPN with MPLS VPN. It is pointed out that there exist questions on applying MPLS to the building of the MAN by analyzing the advantages, existing problems and algorithms on diff-services of MPLS.Combining with the building of the Guangzhou important project—Guangzhou broadband MAN, Guangzhou broadband wireless access network and Guangzhou broadband IP MAN, the existing broadband technologies-POS, DPT, GE, DWDM and the wireless broadband technologies—LMDS, MMDS and expanding frequency communication technology are discussed. The scheme of utilizing the DWDM and LDMS to design MAN is proposed. And the project is the first DWDM broadband network and LMDS broadband wireless network in our country. In addition, aiming to the existing problems of the developing broadband MAN, a novel designing technology, which aimed to the client is proposed. The system is constructed by... |