An Asymmetric Multicast Fingerprinting Scheme Based on Secret Sharing

Many multicast fingerprint schemes have been proposed to protect the digital content´s copyright in multicast environment. In almost all of those schemes, the generation and the embedding of the fingerprint are controlled by the distributors. Since that, the accusation against the charged redistributors, who was the subscriber in some earlier transaction, is objectionable because that the distributor also has access to the fingerprinted copies and, hence, is able to release such a replica on her own. In this paper, we propose an asymmetric multicast fingerprint scheme which is based on the ideal of secret sharing to solve the subscriberpsilas right problem. A trusted third party FCA is employed and the generation of the fingerprint is separated from the embedding of the fingerprint. Our scheme achieves the following properties: (1) Non-frame: the distributor cannot get to know the exact fingerprinted copy that the subscriber receives, Hence the distributor cannot frame the subscriber by forging the copy which the subscriber has got, (2) Non-repudiation: when distributor finds an unauthorized copy, he can identify the guilty subscriber and the subscriber cannot deny, and (3) collusion-secure: the scheme can resist the collusion attack from multi-subscribers. The result is a security, asymmetric multicast fingerprint protocol.