Fingerprinting Schemes. Identifying the Guilty Sources Using Side Information

In a fingerprinting scheme a distributor places marks in each copy of a digital object. Placing different marks in different copies, uniquely identifies the recipient of each copy, and therefore allows to trace the source of an unauthorized redistribution. A widely used approach to the fingerprinting problem is the use of error correcting codes with a suitable minimum distance. With this approach, the set of embedded marks in a given copy is precisely a codeword of the error correcting code. We present two different approaches that use side information for the tracing process. The first one uses the Guruswami-Sudan soft-decision list decoding algorithm and the second one a modified version of the Viterbi algorithm.