Fingerprinting Codes

In the context of digital content distribution, an important problem is tracking the origin of an observed signal to one out of many possible sources. We are particularly interested in settings where no other help is available for achieving this tracking operation except the mere access to the signal itself. We take a quite liberal interpretation of the notion of a signal : it may correspond to data transmission or even to a content related functionality. For instance, it might correspond to the decryption function of a decoder owned by a user where the population of users is defined by the keys they have access to. In another setting, it might be the retransmission of a certain content stream where the copies licensed to each user have the capacity to uniquely identify them.