List of patents

Abstract

The present invention describes a process for authorization and authentication for printed images using halftone cell pattern by colouring or by embossing. It includes steps of, selecting a 2x2 halftone cell combination. Thereafter, forming a grid like halftone letter pattern with predefined values within 3x5 matrix composed of 3x3 windows using 2x2 cells. The information is embedded in each of the 3x3 window sequentially from left to right staring from top row towards the bottom, wherein 3x5 matrix enables to assigning authorization information of the claiming party. . By selecting a key to encrypt the information, a bitwise XOR © is obtained with 15 character information. The encrypted information can be recognised only by the creator by using the secret key thereby providing authentication to the image. The repeated hiding process in every letter of the printed image and the generation of error check bit which is optional, achieves data integrity and lossless data recovery.