SECURING OF DOCUMENTS BY MEANS OF DIGITAL WATERMARK INFORMATION

摘要

Imaging information is inserted into each of several layers (15,17,19) of a document so that the imaging information makes up a total image. In two or more of the layers, the imaging information/data contains pieces (25,27,29) of digital watermark information/data. In the layers, the totality of the digital watermark data forms a security feature for authenticating a document and is inserted in a sectional area of an image surface. Independent claims are also included for the following: (1) A security document; (2) An authenticating method for determining if a document is authentic; (3) An authenticating device for determining if a document is authentic.