Novel multimedia encryption algorithms using chaotic and number theoretic approaches

Abstract

The recent advances in science and technology, especially in information and communication engineering, have led to an exponential increase of multimedia applications over the internet. Applications like military image databases, personal online photograph albums, video-on-demand, video conferencing and pay-per-view demand fast and secure encryption algorithms for providing confidentiality. Multimedia encryption technology provides an end to end security by encoding the raw data into an unintelligible format. Multimedia data are characterized by large volume, high redundancy, high correlation, format compliance and application specific security requirements. These peculiar characteristics demand an extensive and exclusive study of multimedia encryption techniques. Majority of the research works on multimedia encryption techniques are based on chaotic maps. Chaos based multimedia encryption techniques have two major limitations. The first limitation is that, the chosen chaotic maps are to be iterated for sufficiently a large number of times for generation of session keys. This increased number of iterations prevents the usage of chaos based systems in memory limited and low powered devices. The second limitation is that chaos based systems are implemented in floating point arithmetic which may lead to round off errors. Multimedia encryption in certain applications like telemedicine is highly sensitive because even a small amount of visual degradation can lead to false diagnosis. Such applications are to be free from round off errors. In the first part of the research work, the performance of chaos based image encryption is enhanced by hybridization with Number Theoretic approach. The proposed methodology makes use of modular exponentiation of primitive roots of prime over its residual elements for generation of session keys. The key generation process involves only integer arithmetic and hence it is free from round off errors. newline