Anti-collusion Digital Fingerprinting And Coding For Multimedia

Digital fingerprinting is an effective technique to fight against the pirates of digital multimedia, which can trace users by embedding special information with distinct iden-tities into multimedia contents. Conventional fingerprinting techniques cannot resist collusion attack, where a coalition of different users with the same content try to disrupt the underlying fingerprints. AND anti-collusion codes (AND-ACC) were introduced by Trappe et al. to withstand collusion. Logical anti-collusion codes and separable codes, proposed by Cheng and Miao based on AND-ACC, also can resist collusion.The current researches on anti-collusion codes mainly focus on constructing an anti-collusion code or calculating the size of an anti-collusion code. With the basis of pioneers’work, first we study the properties and constructions of AND-ACC and provide a method to construct an AND-ACC by means of pairwise balanced designs (PBDs). According to the relations between separable codes and other mathematical structures, we then investigate the upper bound on the size of2-separable codes of length2and solve it when the size of alphabet q=16,25, in the view of combinatorial designs. In the end, we present a recursive construction for2-separable codes and get a lower bound on the size of2-separable codes.