The Encryption Circuit Research For Safeguard Based On USB

The modern social network has been already popularized gradually, has provided wider space for us, the way that we obtain information is more simple and more convenient, the transmission of information is swifter in speed. But these conflicted with our personal interests sometimes, the protection of personal information seems very important, so we utilize encryption and decryption technology to protect the important information. The method of Protection computer software traditionally is that inputing registration code to verify the legitimacy , and shelling the software, but this operation work on the computer operating system directly, in which the debugging tools can carry on the static and dynamic track using the software such as W32Dasm , SoftIce and TRW2000 ,etc. Through these tools , we can observe the process of the software running, it is relatively apt to duplicate the software.And utilize hardware circuit to protect the software, overcome the shortcoming that the pure software protection, the normal running of the software needs by the cooperation of the hardware circuit, and run short of the powerful analysis tools to the hardware circuit .So we must analysed the hardware circuit and firmware program for duplicating the software, the cost is relatively higher to duplicating the software.This thesis discusses mainly the design of the encryption circuit based on USB interface, it includes that the design of the encryption circuit, the norm of the communication protocol USB1. x , the design of USB customer driver, the computer program, the firmware of the equipment, the algorithm of encryption and decryption: DES and RSA.