Decoding codes with the identifiable parent property

In order to provide copyright protection for digital contents, a distributor can place marks in each copy of a digital object. Placing different marks in different copies, makes each copy unique, and at the same time allows one to trace the source of an unauthorized distribution. This embedding mark technique, known as fingerprinting, was introduced by Wagner (1983). A problem arises when a group of dishonest users collude, compare their copies, and by changing the marks where their copies differ they create a new copy that conceals their identities. Codes with the "identifiable parent property" or IPP codes, provide means of traceability in the presence of a collusion attack. We present a new decoding algorithm for IPP codes, that can also be used to improve the performance of the Silverberg-Staddon-Walker (see Advances in Cryptology - ASIACRYPT2001, 2001) IPP algorithms.