US Patent 7376624 Secure communication and real-time watermarking using mutating identifiers

A multiple party system for distributing content. In one embodiment, four parties are involved in the system: a consumer, a service provider, an authenticator, and a content provider. The distribution of content from the content provider to the consumer is carried out using a predefined protocol, mutating IDs, watermarks, and licenses. The authenticator controls the distribution of mutating IDs, verifies the identity of one or more participating parties, and provides tracking information for mapping service providers and consumers to particular, possibly watermarked, content items.