Research And Implement Of Digital Document Right Management System

Along with the development of information technology and computer network, Enterprise information security problem has been paid more and more attention. Enterprises can prevent from external invasion and attach well depending on certain technology like firewall, intrusion detection and virus killing and so on. But they can not prevent from internal leakage of information. Nowadays most enterprises try to prevent from internal leakage just through improving their management system, not realizing that it can not solve this problem fundamentally. The appearance of Digital Right Management(DRM) help enterprises to protect their digital documents and reduce economic loss. But DRM is not widely put into pratical application, because of the lack of effective access control technology and its inconvenience in use.This paper does research on technologies and systems about DRM finding that most existing DRM systems have defects in file encryption and rights control which are the most important two parts of every DRM system.Most systems uses traditional encryption to encrypt digital files, so users have to do some additional manual operations during encryption and decryption progress.Traditional encryption technology has low security and affects users’ normal usage of files. Access control technology, the key technology of DRM, protects the content of digital files. But existing DRM systems can not prevent from leakage of digital contents, because theirs defective access control function.For examples, Users can simpley leak digital contents by using copying and pasting or using some applications to print screen.Therefore, this paper designs and realizes a digital document rights management system and mainly works on the client part of the system, including the main function frame of the client and the authority model of the system and client’s main function model. The client provides the function of transparent encryption through file filter driver. In contrast with traditional encryption, transparenct encryption completes the encryption operations while the data from memory is written to files and it completes the decryption operations while the data read from files. It has high security and is more effective and has no effects on users’ normal usage. It is an important research area of file encryption. Nowadays, there are many theory researches on it but few pratical applications. Although some DRM systems have function of transparent encryption, they handle all digital files with the same key and it’s very unsafe. But this sytem handles different files in different keys through a management way combined with user model and kernal model.By using windows hook technology,the access control model of the management system realizes the fine grained access control of users’s operation on digital files like cilpborad control and the control of printing screen, including the control of printing screen by some applications that other systems can not control.