Key Technologies Of File Secret Classification Mark In Kernel-Level

With the development of information and computer science, the document security has become a hot topic in information area. A lot of documents are confidential and sensitive, these information are not only related to commercial security, but also related to national security. File Marking and documental encryption make file encrypt in the hard disk and protect documents in different security classification, the researches on secret classification mark based on file system filter are of great importance.This thesis begins from analyzing the situation of current documents protection, draws the conclusion that utilizing Windows File System Filter Driver to implement a kernel file encryption system is an effective way to improve the security of documents in the users'computer.This thesis describes the implementation of an encryption/decryption method and a file security classification module based on file system filter driver. Using file system driver to resolve the problems of documents security would lead to marking various files, encrypting the confidential files.Marking files refer to discriminate the confidential files form common files, discriminate different security classification from confidential files, and for users, the file making must be transparent. The marking of single file and multiple scattered file as well is achieved by embedding file marking in the head of document, there is no restriction on the maximum length of the file marking, thus not only guaranteeing putting all the necessary information into the file marking but also guaranteeing high efficiency and strong reliability of document security protection system.Encryption/decryption refers to make referenced documents into encrypt, guaranteeing the data store in the hard disk in the form of ciphertext. When users need to operate the documents, such as read, write, query document information and so on, the ciphertext should change to plaintext, thus decryption is needed. Therefore, we can make sure the data and documents stored in hard disk in the form of hard disk.