Whim: Watermarking multicast video with a hierarchy of intermediaries

Abstract | Fingerprinting, watermarking content to identify the recipient, provides a good deterrence to unauthorized duplication and propagation of multimedia streams. This is straightforward in a unicast environment � however, in a multicast environment, inserting a ngerprint atthe source does not provide any security since many receivers will share a common ngerprint. A simple solution would be to ngerprint the data for each user at the source and unicast the di erent streams. We aim to achieve a more scalable solution while maintaining and even increasing the level of security. Toachieve this,wehave developed WHIM, a scalable system that allows multicast contenttobemarked with distinct information for distinct receivers securely. This system introduces two new concepts: 1)generating a watermark based on the receiver's location in a tree overlaying the network and 2)inserting the watermark in the content incrementally as it traverses an overlay network. We propose and evaluate several forms of this architecture and show how it improves scalability while increasing security. I