Abstract Existing finite automata public key cryptosystems (FAPKC) are analyzed in this paper. General types of cryptanalytic attacks on FAPKC are discussed and methods of breaking FAPKC by some known types of attacks are introduced. The times needed to perform the usual cryptanalytic attacks on FAPKC are calculated, in order to estimate processing complexity of those attacks. The contrastive analysis of... Existing finite automata public key cryptosystems (FAPKC) are analyzed in this paper. General types of cryptanalytic attacks on FAPKC are discussed and methods of breaking FAPKC by some known types of attacks are introduced. The times needed to perform the usual cryptanalytic attacks on FAPKC are calculated, in order to estimate processing complexity of those attacks. The contrastive analysis of performed attacks’ processing complexities is made to compare the vulnerabilities of FAPKC against discussed attacks. As a result, an improved FAPKC is designed in order to resist the presented types of attacks. Strong FAPKC is obtained by generating invertible nonlinear and linear automata of the suitable form. Read More Read Less

Abstract With respect to the general information hiding problem, a tradeoff is involved between robustness, visibility and capacity. Security of digital multimedia content has become an important issue for content owners and service providers. As watermarking is identified as a major technology to achieve copyright protection. There are many watermarking techniques for data hiding and each of them has some advantages... With respect to the general information hiding problem, a tradeoff is involved between robustness, visibility and capacity. Security of digital multimedia content has become an important issue for content owners and service providers. As watermarking is identified as a major technology to achieve copyright protection. There are many watermarking techniques for data hiding and each of them has some advantages and disadvantages. The robust method for data hiding is embedding the hidden data in the choice of quantizer for the host data. A quality factor is determined to get an appropriate quantization matrix. To modify the bit streams directly during embedding cause unacceptable distortions to cover images. We had developed DCT based entropy Threshold method which determines threshold for each block and only those blocks are selected for whose entropy exceeds by a predetermined threshold for embedding the data. The experimental results show that the proposed scheme has good imperceptibility. Read More Read Less

Abstract This paper proposes a high capacity reversible image watermarking scheme based on enhancement of difference expansion method. Reversible watermarking enables the embedding of useful information in a host signal without any loss of host information. We propose an enhancement of Difference Expansion technique whereby we can embed recursively into multiple layer of payload for grey scale and also RGB color... This paper proposes a high capacity reversible image watermarking scheme based on enhancement of difference expansion method. Reversible watermarking enables the embedding of useful information in a host signal without any loss of host information. We propose an enhancement of Difference Expansion technique whereby we can embed recursively into multiple layer of payload for grey scale and also RGB color scale, hence it increase capacity much better. The proposed technique improves the distortion performance at low embedding capacities and mitigates the capacity control problem. We also propose a reversible data-embedding technique with blind detection of watermark. This new technique exploits the selection of optimum block size to implement the algorithm. The experimental results for many standard test images show that multilevel of embedding increase the capacity when compared to normal difference expansion. There is also a significant improvement in the quality (PSNR) of the watermarked image, especially at moderate embedding capacities. Read More Read Less

Abstract The central challenge with computer security is determining the difference between normal and potentially harmful activity. A promising solution is emerging in the form of Artificial Immune Systems (AIS). These include the theories regarding how the immune system responds to pathogenic material. This paper takes relatively new theory: the Danger theory and Dendritic cells, and explores the relevance of those... The central challenge with computer security is determining the difference between normal and potentially harmful activity. A promising solution is emerging in the form of Artificial Immune Systems (AIS). These include the theories regarding how the immune system responds to pathogenic material. This paper takes relatively new theory: the Danger theory and Dendritic cells, and explores the relevance of those to the application domain of security and evaluating on the Kdd’99 data. Read More Read Less