Transparent Encrypting Office Document Based on Plug-in Software

More and more file encrypting about office document are required in personal application environment. Limitations about encrypting file system, virtual disk encryption and filtrating driver encryption, are analyzed in this paper, then a kind of encryption system for office document, combing with plug-in software and smart u-key, is put forward and implemented. File's encrypting procedure in this system is transparent, self-determination and visible, and the whole system is convenient to migrate. Mow word and excel files can be encrypted using this system.