Abstract: With the development of computer network technology, file information security issue is becoming one of the most attention issues in the field of information security nowadays. Firstly this paper simply analyzes the lack of the current file encryption method, and then it illustrates the principle of transparent encryption and system filter driver. Subsequently the article researches the process of design and implementation of file transparent encryption system, which is based on system filter driver. In the end the paper analyzes the difficulty and lack of the system design.

Key words: information security, transparent encryption, filter driver, IRP, shadow folder