Hash-Based Authentication of Digital Images in Noisy Channels

Abstract

The advancement in digital technology has provided us with a number of software tools that can be used to tamper digital media contents, for example, images. This creates several challenges in case if a digital image is to be used as a legal evidence. Can we use traditional cryto-hashing and digital signatures to meet the integrity and authentication requirements of digital images? Considering an image as a data stream, cryptographic hash functions like Secure Hash Algorithm 1 (SHA1) along with the Rivest Shamir Adleman (RSA) algorithm can be used for integrity verification and authentication. One of the earliest work to adapt this approach was done by Friedman. There are, however, several reasons that actually impede the direct use of cryptographic techniques for solving multimedia security problems. Unlike textual data that is transmitted through a lossless medium, multimedia data like audio, image and video may be transmitted and stored using a lossy medium to save bandwidth and storage space. Therefore, using traditional cryptographic hash functions for integrity verification and authentication of multimedia content has a problem that a single bit change in the content due to lossy medium will significantly change the hash value.