The Research And Realization Of The Digital Signature System In The Document Flow Based On USB-KEY

With the high-speed development of the Information Technology, especially the extensive application of Office Automation System which is based on the network communication technology, the approval of electronic document has been realized, and gradually replaced the means of traditional papery official work. At the same time, the security problem in the process of electronic document flow is deteriorating at an alarming rate, and it is critical to avoid the forgery of documents. Therefore, it is important to have some research on digital signature technology in document flow. According to those requirements, my thesis explores the document flow based digital signature system.Taken into account of all characteristics of the traditional handwritten signature, this paper will research to build a digital signature system for documents share and transfer, to meet the continuously increased demand in The Campus E-Governance. With the knowledge of cryptography, PKI, USB-KEY, and CAPICOM component, and combine The Campus E-Governance security technology, PKI technology with digital signature technology, the system requires unity information from digital certificate in PKI and USB-KEY to identify the ID and grant authority accordingly, both are indispensable. When clients doing the digital signature, the system will simultaneously exam the user's authority limit and effectiveness of digital certificate on-line through the back-end server to ensure the security, and if necessary, it also offers flexible choices of single-user mode and multi-user mode to sign digitally on the body or the abstract of the document.The paper starts with the explanation on the basic theory of digital signature, then researches the cryptography, the digital signature technology and Public Key Infrastructure, and discusses USB-KEY features, CryptoAPI and CAPICOM component of Microsoft, which provide the theoretical basis and technological foundation for the realization of the system. Afterwards, I will analyses the security of document flow in The Campus E-Governance affair, define the target and design principle of the system, and put forward the solution. Simultaneity, as for the framework, flowchart and database of digital signature system which based on the document flow, I will offer the detailed design. Finally, the paper will provide detailed implemental process and introductions of sketch maps on the modules of application and management of digital certificate, safety register in the usage of digital certificate, digital signature and signature validate.