Asian Journal of Engineering and Technology Innovation

Color Image Tampering Detection And Repairing of Tampered Block

Vaibhav Malave, Sarika Deokate, Vikas Nagargoje, Namdev Kadam, Sourabh Aglave

Computer Engineering Department, Indira College of Engineering and Management Parandwadi, Pune.

Abstract

 This is new authentication scheme based on the secret sharing technique with a data repair capability for document type color image via the use of PNG image i.e. portable network graphics images. An authentication signal i.e. a1 and a2 are generated for each block of document type color images, which is transformed into a several shares using the secret sharing Scheme. The characters which is involves are carefully chosen so that many shares as possible are generated and embedded into an alpha channel plane. The alpha channel is then combined with the original image to form a stego image in the PNG format. During the embedding process, the shares which are computed from secret sharing, values of this computed shares are mapped into a range of alpha channel value near their maximum value of 255 to yield a transparent stego image in the PNG format. In the process of image authentication, an image block is marked as a tampered if the authentication signal computed from the current block content does not match that extracted from the share embedded in the alpha channel plane. Data repair scheme is applied to each tampered block after collecting two shares from unmark block.

Keywords:

Authentication, Data Hiding, Secret Sharing, Data Repair.