Image Security With Different Techniques Of Cryptography And Coding: A Survey <s> II. Some Image Encryption Schemes <s> In this paper, methods are shown how to adapt invertible two-dimensional chaotic maps on a torus or on a square to create new symmetric block encryption schemes. A chaotic map is first generalized by introducing parameters and then discretized to a finite square lattice of points which represent pixels or some other data items. Although the discretized map is a permutation and thus cannot be chaotic, it shares certain properties with its continuous counterpart as long as the number of iterations remains small. The discretized map is further extended to three dimensions and composed with a simple diffusion mechanism. As a result, a symmetric block product encryption scheme is obtained. To encrypt an N×N image, the ciphering map is iteratively applied to the image. The construction of the cipher and its security is explained with the two-dimensional Baker map. It is shown that the permutations induced by the Baker map behave as typical random permutations. Computer simulations indicate that the cipher has g... <s> BIB001 </s> Image Security With Different Techniques Of Cryptography And Coding: A Survey <s> II. Some Image Encryption Schemes <s> In this paper, a new image encryption algorithm and its VLSI architecture are proposed. Based on a defined bit recirculation function and a binary sequence generated from a chaotic system, the gray level of each pixel in the image is transformed. The features of the algorithm are as follows: 1) low computational complexity, 2) high security, and 3) no distortion. In order to implement the system, its VLSI architecture with low hardware complexity, high computing speed, and high feasibility for VLSI implementation is also designed. Finally, two encrypted images are simulated and the fractal dimensions of the original and encrypted images are computed to demonstrate the effectiveness of the proposed algorithm. <s> BIB002 </s> Image Security With Different Techniques Of Cryptography And Coding: A Survey <s> II. Some Image Encryption Schemes <s> Due to the rapid growth of digital communication and multimedia application, security becomes an important issue of communication and storage of images. Encryption is one of the ways to ensure high security images are used in many fields such as medical science, military.Modern cryptography provides essential techniques for securing information and protecting multimedia data. In recent years, encryption technology has been developed quickly and many image encryption methods have been used to protect confidential image data from unauthorized access .In this paper survey of different image encryption techniques have been discussed from which researchers can get an idea for efficient techniques to be used. <s> BIB003 </s> Image Security With Different Techniques Of Cryptography And Coding: A Survey <s> II. Some Image Encryption Schemes <s> AbstractThis paper proposes a high security image encryption technique using logistic map. The proposed image encryption algorithm is described in detail along with its security analysis such as key space analysis, statistical analysis and differential analysis. A comparison in terms of correlation between the initial and transformed images, Number of pixels change rate and unified average changing intensity is also done. The present algorithm has been tested using different images to prove that the encryption method has a great potential and has a good ability to achieve the high confidential security. <s> BIB004
We introduce a brief description of the various techniques used for image encryption. A new encryption algorithm based on using the chaotic logistic map produced pseudo random sequence on image and makes double time encryption with improved DES. The combination of Chaos and improved DES makes the final algorithm more secure, faster and more suitable for digital image encryption BIB003 . A new image encryption scheme based on a chaotic system is presented in BIB003 . It is based on power and the tangent function instead of linear function. It uses a chaotic sequence generated by chaotic map to encrypt image data with different keys for different images. Plain-image can be encrypted by the use of the XOR operation with the integer r sequence. A block based transformation algorithm is used in  , where the image is divided into a number of blocks. These blocks are transformed before going through an encryption process. It uses blowfish algorithm for encryption. At the receiver side these blocks are retransformed into their original position and decryption process is performed. It has the advantage of no loss of information in reconstruction of image for the encryption and decryption process. An algorithm using two chaotic systems is in  . One chaotic system generates a chaotic sequence, which was changed into a binary stream using a threshold function. The other chaotic system was used to construct a permutation matrix. Firstly, using the binary stream as a key stream, random the pixel values of the images were modified. Then, the modified image was encrypted again by a permutation matrix. In BIB001 , two kinds of schemes based on higher dimensional chaotic maps are presented. By using a discretized chaotic map, pixels in an image are permuted in shuffling after several rounds of operations between every two adjacent rounds of permutations, a diffusion process is performed, which can significantly change the distribution of the image histogram which makes statistical attack infeasible. Image encryption scheme utilizes the SCAN language to encrypt and compress an image simultaneously in  .Fridrich BIB001 demonstrated the construction of a symmetric block encryption technique based on two-dimensional standard Baker map. There are three basic steps in the method of Fridrich  Choose a chaotic map and generalize it by introducing some parameter.  Discretize the chaotic map to a finite square lattice of points that represent pixels.  Extend the discredited map to three dimensions and further composes it with a simple diffusion mechanism. A chaotic Kolmogorov-flow-based image encryption technique was designed  , in which whole image is taken as a single block and which is permuted through a key-controlled chaotic system. In addition, a shift registers pseudo random generator is also adopted to introduce the confusion in the data. An encryption method called BRIE based on the chaotic logistic map is presented in BIB002 . The basic principle of BRIE is bit recirculation of pixels, which is controlled by a chaotic pseudo random binary sequence. The secret key of BRIE consists of two integers and an initial condition of the logistic map. An encryption method called CKBA (Chaotic Key Based Algorithm)  , in which a binary sequence as a key is generated using a chaotic system. The image pixels are rearranged according to the generated binary sequence and then XORed and XNORed with the selected key. An image encryption algorithm using logistic map in BIB004 , uses a chaotic map with suitable initial condition for varying the pixel values randomly with respect to its initial values of the original image. Next the chaotic sequences of the logistic map are used for pixel shuffling. The algorithm uses a secret key of 32 characters (256-bits). A chaos-based image encryption scheme was introduced in  ]. An image is first converted to a binary data stream by masking these data with a random keystream generated by the chaos-based PRKG, the corresponding encrypted image is formed. In most of the previous algorithms a security analysis is made; such as key space analysis, statistical analysis and differential analysis. A comparison between original image and encrypted image in terms of correlation between the initial and transformed images, number of pixels change rate and unified average changing intensity are also performed.