Distributed multicast of fingerprinted content based on a rational peer-to-peer community

Keywords: Co-utility Multicast fingerprinting Anonymous fingerprinting Game theory a b s t r a c t In conventional multicast transmission, one sender sends the same content to a set of receivers. This precludes fingerprinting the copy obtained by each receiver (in view of redistribution control and other applications). A straightforward alternative is for the sender to separately fingerprint and send in unicast one copy of the content for each receiver. This approach is not scalable and may implode the sender. We present a scalable solution for distributed multicast of fingerprinted content, in which receivers rationally cooperate in fingerprinting and spreading the content. Furthermore, fingerprinting can be anonymous, in order for honest receivers to stay anonymous. Copyright protection techniques have gained widespread attention by both academia and industry in the recent years. Home Internet access and the increased bandwidth of communications have contributed to the explosion of copyright-breaking copying of digital contents. In this context, fingerprinting emerged as a convenient technology to fight against unlawful digital content distribution [6,4]. Fingerprinting techniques consist of embedding a transparent watermark into the protected content in such a way that a unique identifier exists for each buyer of the content. This identifier can be extracted later on and might be used to trace and match an illegal distributor of the content. This makes it possible to undertake the appropriate legal actions against such treacherous buyers. Fingerprinting schemes can be classified in three different categories [7], namely symmetric, asymmetric and anonymous. In symmetric fingerprinting, the embedding of the fingerprint is performed by the merchant only and, thus, it provides no valid evidence of a treacherous behavior of a buyer (since the merchant herself could be the illegal distributor). In asymmetric fingerprinting, the embedding is performed using a protocol designed in such a way that only the buyer obtains the fingerprinted copy of the content. This makes it possible to prove the illegal distributor's treachery to a third party. Finally, anonymous fingerprinting retains the asymmetric property and also protects the privacy of buyers, whose identity is only revealed and disclosed in case of illegal distribution. From the point of view of a buyer, anonymity is a valuable property and several protocols have been proposed for anonymous fingerprinting. However, current anonymous fingerprinting proposals in the literature (see Section 2.3 below for a brief review) place a substantial computational and communication burden on the merchant. The merchant's overhead is …