Improved existence bounds on IPP codes using the Clique Lovász Local Lemma

Nowadays, one of the biggest problems that challenges distributors of digital content is, precisely, protecting such content against redistribution. Those who trade with any of the multiple digital information formats (audio, video, software, text, etc.) face one danger: once a copy of the content is purchased by a client, this user may illegally redistribute it. This way, a distributor of digital content with intellectual property rights must take some steps to ensure the preservation of its business and, given that the use and benefit of a legally purchased copy of the content by a client implies reading the data (either with a computer, a DVD player, or any other device), anti-copy protection of such copyrighted content is not viable. Here is where new mechanics such as fingerprinting (first presented in [18]) take place: instead of distributing identical copies of the data, fingerprinting consists of embedding a series of marks on each copy, with each mark unique for each user and keeping record of which mark is received by which user, thus dissuading them from redistributing the files, under the threat of being caught. Once the distributor intercepts an illegally distributed copy, he will be able to read the marks to determine which user is guilty, and therefore, the user is labelled as a traitor.Peer Reviewe