Design And Realization Of Network File Cryptographic System

In recent years, with more and more computers, the computer network has had a great development. But when transmitting information rapidly and conveniently, the network makes more and more security problems. The network file encryption system in this paper is an efficiency mode to ensure the information be transmitted in the network securely. And it will be very useful.Relative to the network file encryption tools at present, which is slow, can be broken easily, and the keys management is not secure, this paper puts forward a new scheme of network file encryption system based on encryption card in Windows and realizes it. The system adopts the combination of software and hardware. It includes IC cards, an IC cards' reader, an encryption card, the encryption card's driver and the application. The system decreases the cost of transmitting files by special network based on ensuring the security. Furthermore, it increases speed, security and reliability by using hardware.Firstly, the paper explains the subject's significance and confirms the problems to be settled. It analyzes cryptography, which is the basic technology. Analyzing and illuminating the system's whole design, the paper designates the application mode and environment and explains the system's components. It puts forwards a new symmetric keys management scheme based on the public key table. In the scheme, adopting the two-dimension user key table settles the problem of isolation of user key. The scheme makes the system more efficient and more secure. The paper also explains the system's operation flow and functions. After them, it researches namespace and Shell of Windows in application. Then it explains the realization of main parts, including the main interface, the timely operation and the course of encrypting and decrypting. At last, it tests the speed parameters of the system to prove the high speed.