A class of non‐linear asymptotic fingerprinting codes with ε ‐error

Pupose – The purpose of this paper is to show that a fingerprinting code is a set of code words that are embedded in each copy of a digital object, with the purpose of making each copy unique. If the fingerprinting code is c ‐secure, then the decoding of a pirate word created by a coalition of at most c dishonest users, will expose at least one of the guilty parties. Design/methodology/approach – The paper presents a systematic strategy for collusions attacking a fingerprinting scheme. As a particular case, this strategy shows that linear codes are not good fingerprinting codes. Based on binary linear equidistant codes, the paper constructs a family of fingerprinting codes in which the identification of guilty users can be efficiently done using minimum distance decoding. Moreover, in order to obtain codes with a better rate a 2‐secure fingerprinting code is also constructed by concatenating a code from the previous family with an outer IPP code. Findings – The particular choice of the codes is such that it allows the use of efficient decoding algorithms that correct errors beyond the error correction bound of the code, namely a simplified version of the Chase algorithms for the inner code and the Koetter‐Vardy soft‐decision list decoding algorithm for the outer code. Originality/value – The paper presents a fingerprinting code together with an efficient chasing algorithm.