Techniques of File System Filter Driver-based and Security-enhanced Encryption System

User-mode encryption systems require users manually do encryption or decryption when they want to access a file,in some of those systems the file may reside in cleartext on disk while the user is actively working on it.Encryption file systems decrease the user interaction and guarantee the files in disk is in cipher-text,but those systems are complex in design and realization.In this paper the encryption system is based on Windows NT driver model and file system filter driver to deal with data on the fly.It overcomes the disadvantages of both usermode encryption systems and encryption file systems.Additionally,through storing the encryption key in the smart card the system security is enhanced.