In this paper, a novel image encryption scheme is proposed based on combination of pixel shuffling and new modified version of simplified AES. Chaotic baker's map is used for shuffling and improving S-AES efficiency through S-box design. Chaos is used to expand diffusion and confusion in the image. Due to sensitivity to initial conditions, chaotic baker's map has a good potential for designing dynamic permutation map and S-box. In order to evaluate performance, the proposed algorithm was measured through a series of tests. These tests included visual test and histogram analysis, randomness test, information entropy, encryption quality, correlation analysis, differential analysis and sensitivity analysis. Experimental results show that the new cipher has satisfactory security and is more efficient than AES which makes it a potential candidate for encryption of multimedia data.

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Since various pseudo-random algorith ms and sequences are used for cryptography of data or as init ial values for starting a secure communicat ion, how these algorith ms are analyzed and selected is very important. In fact, given the g rowingly extensive types of pseudorandom sequences and block and stream cipher algorith ms, selection of an appropriate algorith m needs an accurate and thorough investigation. Also, in order to generate a pseudo-random sequence and generalize it to a cryptographer algorith m, a co mprehensive and regular framework is needed, so that we are enabled to evaluate the presented algorith m as quick as possible. The purpose of this study is to use a number of pseudo-random number generators as well as popular cryptography algorith ms, analyze them in a standard framework and observe the results obtained in each stage. The investigations are like a match between d ifferent algorith ms, such that in each stage, weak algorith ms are eliminated using a standard method and successful algorith ms enter the next stage so that the best algorith ms are chosen in the final stage. The main purpose of this paper is to certify the approved algorithm.

Confidentiality of digital images is an important requirement for many multimedia applications and services. To maintain confidentiality, encryption of digital images is essential. Digital images are usually very large and encrypting such bulky data induces many performance overheads, which can be too expensive for real-time applications in resource constrained environments. In this paper, we propose a chaotic image encryption scheme which satisfies the need for both lightweightedness and security. To justify the security and efficiency, the new cipher was evaluated using a series of statistical tests. These tests included a visual testing and a histogram analysis, a randomness analysis, a correlation analysis, an entropy analysis and an image encryption quality analysis. Based on all analyses and experimental results, it is concluded that the proposed scheme is effective, efficient and trustworthy and therefore can be adopted for image encryption.