Fundamental Incomplete Cryptography Method to Digital Rights Management Based on JPEG Lossy Compression

Generally, DRM(Digital Rights Management) system is achieved with individual function modules of cryptography, watermarking and so on. In this typical system flow, all digital contents are temporarily disclosed with perfect condition via decryption process. This paper describes the fundamental idea of a novel DRM method which is composed of an incomplete cryptography and user identification mechanism to control the quality of digital contents. Our proposed prototype JPEG codec based on a simple incomplete cryptography can easily control the open level of contents, besides at decoding process, an identification code embedded with an authorized key is used to prevent unauthorized duplication or business of digital contents. Experimental results with simulation confirmed that the modified codes keep compatibility with standard JPEG format, and revealed that the proposed method is suitable for DRM in the network distribution system.