Abstract: The invention provides a data processing system capable of securing files. The data processing system of the invention divides a data storage device into an unprotected space and a protected space. A protected application resided in an operating system is controlled by an application controlling module residing in the operating system. When the application controlling module receives a file access request information transmitted from the protected application, the application controlling module redirects the file access request information to access a plurality of protected files stored in the protected space in accordance with the file access request information, and then to return the access result of the protected files to the protected application.

Abstract: The invention provides a data processing system capable of securing files. The data processing system of the invention divides a data storage device into an unprotected space and a protected space. A protected application resided in an operating system is controlled by an application controlling module residing in the operating system. When the application controlling module receives a file access request information transmitted from the protected application, the application controlling module redirects the file access request information to access a plurality of protected files stored in the protected space in accordance with the file access request information, and then to return the access result of the protected files to the protected application.

Abstract: This invention provides a digital information protecting method executed in an author and a client computer, both having a predetermined information processing software to process a piece of digital information. In the author computer, receive a content key from a server and encrypt the piece of digital information by the content key. Encrypt the content key by a predetermined key encrypting process. Transmit the encrypted information and encrypted content key to the client computer. In the client computer, decrypt the encrypted content key by a corresponding predetermined decrypting process. Decrypt the encrypted information by the content key so that the piece of digital information can be used by the client computer. No matter the client computer is on-line or off-line, it can get the key and decrypt the piece of digital information.