  In general, DRM (Digital Rights Management) system is responsible for the
safe distribution of digital content, however, DRM system is achieved with
individual function modules of cryptography, watermarking and so on. In this
typical system flow, it has a problem that all original digital contents are
temporarily disclosed with perfect condition via decryption process. In this
paper, we propose the combination of the differential codes and fragile
fingerprinting (DCFF) method based on incomplete cryptography that holds
promise for a better compromise between practicality and security for emerging
digital rights management applications. Experimental results with simulation
confirmed that DCFF keeps compatibility with standard JPEG codec, and revealed
that the proposed method is suitable for DRM in the network distribution
system.
