	US 7,542,587 B2
	Content processing methods using reversible watermarking
Jun Tian, Edison, N.J. (US); John Stach, Tualatin, Oreg. (US); and Neil E. Lofgren, Portland, Oreg. (US)
Assigned to Digimarc Corporation, Beaverton, Oreg. (US)
Filed on Mar. 06, 2007, as Appl. No. 11/682,802.
Application 11/682802 is a division of application No. 10/319380, filed on Dec. 13, 2002, granted, now 7,187,780.
Claims priority of provisional application 60/340651, filed on Dec. 13, 2001.
Prior Publication US 2007/0201722 A1, Aug. 30, 2007
Int. Cl. H04K 1/00 (2006.01)

U.S. Cl. 382—100 [713/176]

9 Claims

1. A method comprising:

receiving a first content object, the first object being steganographically encoded with a first robust digital watermark conveying first payload information;

decoding the first watermark, and storing at least certain of said payload information;

removing the first digital watermark from the object by reference to the decoded payload information and watermark encoding parameters;

changing the content object from which the first watermark has been removed;

storing data relating to the changes in an audit log;

encoding the changed content object with a second robust digital watermark, the second watermark conveying second payload information different than the first payload information.