Matrix-based robust joint fingerprinting and decryption method for multicast distribution of multimedia

This paper addresses the problem of unauthorized redistribution of multimedia content by malicious users (pirates). The solution proposed here is a new joint fingerprinting and decryption method which meets the requirements for both imperceptibility and robustness of fingerprints and scalability in terms of design and distribution of fingerprinted multimedia content. The proposed method uses a simple block cipher based on matrix multiplication to encrypt images which are then sent to all users via multicast transmission. Individual decryption keys are designed depending on the users' fingerprints so that a different fingerprint will be introduced into the image during decryption for each unique decryption key. Encryption and fingerprinting are performed on DCT coefficients, which results in high robustness against compression, low-pass filtering, scaling, etc. The experimental results show that the proposed method is robust against collusion attacks and compression. (C) 2014 Elsevier B.V. All rights reserved.