Patent ID: 7206431

Claim:
A method for verifying a self-authenticating document, comprising the steps of: (a) obtaining an image of at least a predetermined portion of the document; (b) dividing the image into a predetermined number of pixel groups, each pixel group including a plurality of pixels; (c) determining pixel characteristic data for each pixel; (d) determining a pixel group classification data for each pixel group as a function of the pixel characteristics data of at least one pixel in the pixel group; (e) generating a characteristic digital data “CDD” for the image as a function of the pixel group classification data and a location of the corresponding pixel group in the image; (f) adding the CDD to the document; (g) upon a request for verification of the document, extracting the CDD from the document; (h) repeating steps (a)–(e) to generate a further CDD based on the image; and (i) verifying the document if the CDD is substantially identical to the further CDD.