File Transparent Encryption System Design Based on Security Directory

Using the Minifilter framework and AES group encryption algorithm, the paper develops a filter driver for encrypting the file of particular types under the security directory. The principle of the file system filter driver is discussed here, and makes a special research about the file operation process especially for word format. This paper also makes a deep analysis of transformation mechanism between the plaintext and ciphertext, and the implementation algorithms of encryption and decryption. Finally, the paper describes the method of path filtering in detail.