The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 21, 2003
Filed:
Oct. 08, 1999
Joerg Schwenk, Dieburg, DE;
Johannes Ueberberg, St. Augustin, DE;
Deutsche Telekom AG, Bonn, DE;
Abstract
In a method for embedding collusion-secure digital fingerprints in electronic documents, using a geometric order system one point in the projective space PG (d, q) is unambiguously assigned to each flagging position in a document via a secret function. At least two hyperplanes of PG (d, q) are assigned to each fingerprint, each being exclusively assigned to one fingerprint only, and for each fingerprint precisely those flagging positions that correspond to the points of the selected hyperplane are flagged. To trace attempts to delete fingerprints, an intersection of hyperplanes is reconstructed from the flagged flagging positions that have been found in the document, by analyzing linear dependencies the hyperplanes are determined, and by calculating these hyperplanes the fingerprints of colluding customers may be determined.