AUTHENTICATION OF GRAYSCALE DOCUMENT IMAGES

Abstract

In this paper an authentication method for grayscale document images which is based on secret sharing technique with self repairing capability via the use of the Portable Network Graphics image has been described. In this approach the original grayscale document image is converted into stego image by adding the alpha channel plane. The stego image is in the Portable Network Graphics (PNG) format. This stego image is transmitted over the network. The authentication process is applied on the stego image on the receiver side. In the authentication process the data extracted from this stego image is compared with the data computed from the binary version of the stego image. If the data is matched the image is considered to be authentic. Else the tampered blocks are marked and the image is self repaired using inverse secret sharing scheme.