Abstract.The

Communication has to be secure in order to be kept private. The latest developments in the field of digital communication have made secret communication possible. Image hiding is a method in which a secret image is hidden in a cover image thereby forming a hybrid or stego image. In this paper, data hiding is performed by taking difference value of three and two neighbouring pixels by adapting Zig-Zag traversing scheme (ZZTS). This method enhances security and the quality of image in spite of high capacity of concealed information. Error correction mechanism using hamming code is applied to ensure reliable secret communication. The effectiveness of the proposed stego system has been estimated by computing Mean Square Error(MSE),Peak Signal to Noise Ratio (PSNR), Mean Structural SIMilarity index(MSSIM) and Bits per colour Pixel. This paper also illustrates how security has been enhanced using this algorithm

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Imaging applications generate large volumes of data leading to challenges for transmission and storage. In this paper a novel hybrid image compression technique for efficient storage and delivery of data is proposed. It is based on decomposing the data using daubechies-4 wavelet in combination with the lifting scheme and entropy encoding. This scheme is concerned with the compression ratio, bits per pixel and peak signal to noise ratio. Experimental results illustrate that the proposed scheme is efficient and feasible in terms of compression ratio, bits per pixel and peak signal to noise ratio.

Reduction-of-Quality (RoQ) attack is a type of Distributed Denial-of-Service (DDoS) attack that is difficult to detect in current computing systems and networks. These RoQ attacks throttle the throughput heavily and reduce the Quality of Service (QoS) to end systems gradually rather than refusing the clients from the services completely. In this paper, we propose to develop a flow monitoring scheme to defend against such attacks in mobile Ad-hoc networks. Our proposed defense mechanism consists of a flow monitoring table (FMT) at each node to identify the attackers. If the channel continues to be congested because some sender nodes do not reduce their sending rate, it can be found by the destination using the updated FMT. Once the attackers are identified, all packets from those nodes will be blocked. By simulation results, we show that our proposed scheme achieves higher throughput and packet delivery ratio with reduced packet drop for legitimate users.