Process for inserting tamper-proof digital fingerprints into electronic documents

摘要

The invention is directed to a method for introducing manipulation-proof digital fingerprints into electronic documents, which makes it possible to detect manipulations by buyers or groups of buyers. DOLLAR A According to the invention, based on a predetermined number of copies and a maximum number of cooperating attackers for the document, a position or area for the digital fingerprint of the customer is defined for each copy. All points and areas defined for the digital fingerprints within the framework of the document are, as a whole, subject to a self-contained, finite geometric ordering system in which overlaps of the digital fingerprints occur at defined points or areas. The attackers involved in the manipulation can be clearly identified on the basis of the evaluation of the interfaces not found by the attackers. DOLLAR A The method according to the invention is particularly suitable for marking copies of documents which are subject to copyright protection.