US 7,562,228 B2 Jul. 14, 2009
The subject matter includes systems, engines, methods, and schemata for embedding spread-spectrum fingerprints in multimedia content: a first fingerprint to identify a recipient of the multimedia content and a second fingerprint at a location in the first fingerprint that represents a subset of a much larger group of recipients. By locating the second fingerprint, the search for a media pirate is immediately narrowed down to the subset, thus immensely speeding up pirate identification. In one implementation, chips of the second fingerprint can be made small and embedded sparsely, making alteration difficult. Systems, engines, methods, and schemata for synchronizing a pirated copy with original multimedia content to facilitate fingerprint recovery are also described.
21 Claims, 10 Drawing Sheets