Research And Implement Of Transparent Encryption And Decryption System Based On File Filter Driver

In our daily learning and working, the continuous development of the Internet makes information collection, dissemination and scale reached an unprecedented level. Information may be illegal eavesdropped, intercepted, tampered and destroyed in its storing sharing and transmission, which results immeasurable loss. Especially in some important sectors, such as banking systems, security systems, business systems and government departments, the information security problem is more important in information storage and transmission in a communication network. The information usually exists in the computer and removable storage media in the form of electronic document, which is easily disclosed in its transmission. So the document security problem has become one of the important issues in the field of information science today. The traditional technology such as firewall and intrusion detection technologies cannot solve all the security issues within the network operating system, because they cannot handle the active leakiness by the internal staff. One of the commonly used methods to deal with intranet operation system level is file encryption and decryption technology based on modern cryptography, which is realized by the file transparent encryption and decryption technology using file system filter driver.This article designed and implemented a transparent encryption and decryption system based on file filter driver through the investigation and study of the file security issues. The key features of this system-file encryption and decryption-is realized in the Windows operation system kernel module, which reaches a high security level. And the Complexity of this system developing is easy because the file filter driver based on Minifilter released by Microsoft recently. The file transparent encryption and decryption system designed in this paper contains two main modules-user control program in user module and file system encryption and decryption driver in kernel module. The user control program specifies the file encryption rules, and transfer the rules to the driver. The main functions of the file transparent encryption and decryption driver are receiving the request from the user control program and encryption and decryption the file operations in kernel module. The operations needed to focus on are the type of create, read, write, cleanup, close, etc. In the process of create type operation this system creates some data structure records for following operation. In the process of write operation the file contains are encrypted and In the process of read operation the file contains transform from the lower driver are decrypted. Function testing show that this system implements the function of transparent encryption and decryption while the user cannot feel the process.