Design And Implement Of File Protection System Based On File System Filter Driver

Enterprise's interior documentation has become a kind of important property of an enterprise.The security of current file protection system in the application layer is far more less than the user's needs,and the stability and efficiency of encryption and decryption of file protection system in the core layer can not be satisfactory.This paper designs a file protection system which combines the safety of file system filter driver and the efficiency of USBKey cryptographic hardware.It ensures the safety of user's documentation through legitimate user authentication,hidden files,denied access and the encryption of file contents.File filter driver captures the file data,then the data is written to disk after USBKey encrypted when file is saved.File filter driver returns plaintext data to the user after USBKey decrypted when file is read.This system uses the most secure file header encryption identifies and implements a set file length control rules which greatly solute the problem of file length generated by file header encryption identification.By processing the change of file encryption and decryption needs because of renaming,the system implements the normal use of office series documents which has a large number of temporary files in the process of save.The system also ensure that file header encryption identification will not be inconsistent caused by intermediate temporary files in the process of save.The final tests prove that the security and ease of the system is greatly improved comparing to the general application layer file protection system.And comparing to traditional filter driver encryption system,the encryption and decryption efficiency and security of the system is also improved to some extent.In addition,the system can handle multiple types of files,and has high stability and great practical value.