The Design And Implement Of Transparent Encryption And Decryption Technology In File Protection System

With the popularity of computer and network applications, information security problems are becoming attracted increasingly attention. The current information security issues, not only from outside attacks, but also from the inside secrets and destruction. Alonely to improve the management is difficult to fundamentally put an end to internal security problems, it is necessary to use some technical method to protect internal data file, file protection system is emerged.Encryption and decryption technology is the core technology of file protection system. In this paper, comparing the the advantages and disadvantages of different types of file encryption technology, through analysis the security needs, come to the kernel layer transparent encryption technology that based on FSFD combined with USB Key is the most economicly and efficiently method to achieve File Protection system.The paper begins form analyzing the Windows architecture struct, especially the main system components that the file system associated with, such as I/O Manager, Object Manager. The paper analyzes the File System and Filter Driver. The paper also tells us how to achieve transparent encryption and decryption functions and introduces basic knowledge of cryptography.In this study, this paper designed a Windows-based file system filter driver of file protection system. Meanwhile, we studied out a frame diagram which covered whole function system, including kernel layer function modules archieve processes, as well as the definition of important data structures. For transparent encryption and decryption key technology to achieve a more detailed paper on this. Through analysis of key technologies, summed up the advantages and disadvantages, and ways to improve future prospects.The main work of the thesis are outlined as follows: based on the combination of USB Key access control technology and file system filter driver, file protection system is given the role of division and set up permissions in order to achieve the safety management. , Finally, in the test platform, the file protected system that this paper studied is tested. Test results show that the system in the Windows NT 5 Series platform is performance well. The System is able to protect internal data files.