Safety Management Method For An Electronic Document

Abstract

A method of encrypting/decrypting the document and a safety management storage device and system method of its safety management, using for the safety management of electronic documents, the said system comprising a PC or mainframe installed with common reading software and a storage device of safety management connected to the said PC/mainframe through hot-plug; when connected to the mainframe, the said storage device is enumerated as a USB CDROM device at least. The user owns the said storage device can encrypt the electronic documents by using the encryption keys to generate an encrypted document with the same file type, also can open the encrypted document by using common reading software, and then use the document according to the predetermined operation authority.

What is claimed is: 
     
         1 . A safety management method for an electronic document, comprising steps of:
 setting up at least a storage device for safety management, and writing at least one encryption or decryption key into its storage unit;   distributing said storage device for safety management to a predetermined user;   connecting, by said predetermined user, said storage device to a PC or mainframe with Windows operation system so that said device should be enumerated as a USB CDROM device by the system;   injecting, by a loading program in said storage device, an encryption or decryption module into a scheduled program process of a common reading software in the PC or mainframe through a remote thread injection and function hook so as to take over the scheduled operation ran by said common reading software; and   encrypting the electronic document of a predetermined file type to generate encrypted electronic document with a same file type, or open a decrypted electronic document having a predetermined file type where the encrypted electronic document has a same predetermined file type by using said common reading software.   
     
     
         2 . The safety management method of according to  claim 1  wherein the storage device for safety management can be distinguished into parent device and subsidiary device, endowed with different management authority. 
     
     
         3 . The safety management method of according to  claim 2  wherein a plurality of certified encryption keys are saved in the storage media of said parent device; they can be transmitted from the parent device inserted into a PC or mainframe to a subsidiary device, or be backed up between the parent devices. 
     
     
         4 . The safety management method of according to  claim 1  wherein encrypting an electronic document comprises setting encryption information including information of authority and serial number of keys, and wherein after the opening of encrypted electronic document, said common reading software is managed under an operation authority. 
     
     
         5 . The safety management method of according to  claim 1  wherein an authority saved in said storage device for safety management is updated through the mainframe or net; said update comprises: writing scheduled invalid data into the storage device to invalidate an encryption key and relevant information.