A random grid is a 2-dimensional array. Each pixel in random grid is either transparent or dark. Darkness and transparency of each pixel are determined by a total random process. This paper introduces a new method for multi-Image encryption by random grids. In the proposed method، three binary Images are encrypted by only two random grids in such a way that each random grid does not give the attacker any information. Binary Images can not be decrypted and reconstructed only when two random grids are accessible. Decryption process is done by XOR operation. The result of implementation of the proposed method showed that reconstructed Images have higher visual quality in comparison with previous approaches.

An Image is a visual representation of something that has been created or copied and stored in electronic form. Securing Images is becoming an important concern in today’s information security due to the extensive use of Images that are either transmitted over a network or stored on disks. Since public media are unreliable and vulnerable to attacks, Image encryption is the most effective way to fulfil confidentiality and protect the privacy of Images over an unreliable public media.In this paper a new Image encryption algorithm based on Advanced encryption Standard and DNA sequence is proposed. We present how to encode and decode data in a DNA sequence based on Codon replacement and how to perform the different steps of AES based DNA. The algorithm is implemented in MATLAB 2012b and various performance metrics are used to evaluate its efficacy. The theoretical and experimental analysis show that the proposed algorithm is efficient in speed and precision. Furthermore, the security analysis proves that proposed algorithm has a good resistance against the noise and known attacks; So that Unbreakability of proposed algorithm is 37.48% better than the compared algorithms.

A new Image encryption algorithm is proposed, in which a novel chaotic map is introduced to generate the random sequence. The mentioned sequence is employed to produce gray level values. The original Image is encrypted by applying the XOR operator to every pixel using the mentioned values. Our chaotic map provides a large degree of randomization compared to existing approaches and therefore, the correlation between adjacent pixels in the encrypted Image is reduced substantially. The security analysis demonstrates that the new algorithm is highly secure. As it is shown in the experimental results, our algorithm improves entropy, key sensitivity, and correlation. Specifically, the amounts of entropy and correlation measures are very close to the optimal values. It is also very robust against the noise. The PSNR of decrypted Images are degraded slightly with the increasing noise strength. Additionally, the suggested approach leads to smoother histograms in comparison to the previous algorithms.

Information security is one of the most important defensive issues that prevents the intruders' attacks to the privacy of organizations valuable data. Cryptology is one of the most powerful tools of Passive defence that assures the security of communication and information technology. In this paper, we propose a new Image encryption scheme using chaotic maps to protect the distribution of digital Images in an efficient and secure way. The new encryption scheme is implemented using MATLAB to check its efficiency. Moreover, a series of tests and some comparisons have been performed to justify efficiency of Image encryption method. These tests included key space analysis, psychophysical experiments, histogram analysis, information entropy, encryption quality, correlation analysis, differential analysis and key sensitivity analysis. Simulation experiment has validated the effectiveness of the proposed system.

In this paper, a new structure for Image encryption using recursive cellular automata is presented. The Image encryption contains three recursive cellular automata in three steps, individually. At the first step, the Image is blocked and the pixels are substituted by reversible cellular automata. In the next step, pixels are scrambled by the second cellular automata and at the last step, the blocks are attached together and the pixels are substituted by the third cellular automata. Due to reversibility of cellular automata, the decryption of the Image is possible by doing the steps reversely. The experimental results show that encrypted Image is not understandable visually, also this algorithm has satisfactory performance of quantitative assessment from some other schemes.

encryption is one of the most powerful tools that ensures information security in the field of communication and information technology. Image encryption is different from other encryptions. This difference is due to the inherent characteristics of the Images. Recent attempts to encrypt Images have been based on chaos. In this paper, a new chaos-based encryption algorithm for Image encryption is presented. In the proposed method, instead of encryption one Image in each step, four Images are encrypted simultaneously. In this way, four standard Images are combined and a single Image of their combination is created. Simultaneous encoding of four Images will cause to complicate the proposed encryption algorithm, increase security, and extend the amount of gray area per pixel. Finally, the resulting Image is XORed with encryption key and the encrypted Image is generated. Considering the combination of four Images and their simultaneous encoding, as well as examining a large number of Image evaluation criteria, specifically the information entropy, that has achieved a value equal to 7/9994 in our proposed algorithm, which is really close to the ideal value of 8, shows that the proposed algorithm performs appropriately.

A new Image encryption scheme using the advanced encryption standard (AES), a chaotic map, a genetic operator, and a fuzzy inference system is proposed in this paper. In this work, plain Images were used as input, and the required security level was achieved. Security criteria were computed after running a proposed encryption process. Then an adaptive fuzzy system decided whether to repeat the encryption process, terminate it, or run the next stage based on the achieved results and user demand. The SHA-512 hash function was employed to increase key sensitivity. Security analysis was conducted to evaluate the security of the proposed scheme, which showed it had high security and all the criteria necessary for a good and efficient encryption algorithm were met. Simulation results and the comparison of similar works showed the proposed encryptor had a pseudo-noise output and was strongly dependent upon the changing key and plain Image.

With the development of the internet and social networks, the multimedia data, particularly digital Images, has been of increasing interest to scientists. Due to their advantages including high speed, high security, and complexity, chaotic functions have been broadly employed in Image encryption. The present paper proposed a modified logistic map function which resulted in higher scattering in the obtained results. Confusion and diffusion functions, as the two main actions in cryptography, are not necessarily performed in order, i. e. each of these two functions can be applied on the Image in either order, provided that the sum of total functions does not exceed 10. So, to calculate the sum of functions, confusion has the factor of 1 and diffusion has the factor of 2. To simulate this method, a binary stack was used. Application of binary stack and pseudo-random numbers obtained from the modified chaotic function increased the complexity of the proposed encryption algorithm. The security key length, entropy value, NPCR and UACI values, and correlation coefficient represented in the analytical results revealed the capability and validity of the proposed method. Analyzing the obtained results and comparing the algorithm to other investigated methods clearly verified high efficiency of the proposed method.