Secure image authentication by distibuted source coding using LDPC encoding

Abstract

Image authentication is a process of verify the originality of an image by detecting malicious manipulations. It is important in content delivery via entrusted intermediaries, such as peer-to-peer file sharing. Many differently encoded versions of the original image might exist. We propose an approach using distributed source coding using mean projection and LDPC encoding method for the image authentication problem. The key idea is to provide mean projection and LDPC encoded quantized image projection as authentication data. This version can be correctly decoded with the help of an authentic image as side information. Distributed source coding provides the desired robustness against legitimate variations while detecting illegitimate modification. The decoder incorporating mean projection and LDPC algorithms can authenticate images which have undergone contrast, brightness, and affine warping adjustments.