AUTHENTICATION OF PHYSICAL AND ELECTRONIC MEDIA OBJECTS USING DIGITAL WATERMARKS
10/26/2010 12:00:00 AM
A content watermarking method derives a watermark key from data representing content. In one particular method, a plural symbol message is algorithmically transformed in dependence on the derived watermark key. In another arrangement, the key specifies how or where the message is embedded in the content. A variety of other features and arrangements are also detailed.