Memory Cellular Automata Research Articles

An Effective Reversible Data-Hiding in Encrypted Images Using Memory Cellular Automata

This article attempts to propose an effective reversible data-hiding in encrypted images using memory cellular automata. The image content owner encrypts the original image using a Paillier homomorphic encryption algorithm with an encryption key and uploads the encrypted image into the cloud server. Then, the data hider embeds additional data into the encrypted image with an embedding key. Whenever the user gets both keys, the original image can be recovered without any errors. Compared to existing reversible data-hiding in encrypted image methods, the proposed method has better embedding rates, embedding payloads, and high-security performance.

Fourth Order MCA and Chaos-Based Image Encryption Scheme

This paper presents a fast and efficient cryptosystem for enciphering digital images. It employs two of the most prominent dynamical systems-chaotic maps and cellular automata. The key streams in the proposed encryption scheme are derived from the SHA-256 hash function. Hash functions produce the digest of the input plaintext, known as a hash value, which can be considered as a unique signature of the input. This makes the keys more plaintext dependent, which is a desirable property of a robust cryptosystem. These key streams are used as the secret keys (i.e., initial conditions and control parameters) of an improved one-dimensional (1-D) chaotic map, i.e., the Logistic-Sine map. As far as we know, this paper is a first that combines the well-known diffusion-confusion architecture and the fourth order 1-D memory cellular automata (MCA) for image encryption. First, a pixel-wise XOR operation is applied to the original image, followed by a pixel-wise random permutation. The resulting image is decomposed into four blocks according to the quadtree decomposition strategy. Then, a fourth order reversible MCA is applied, the blocks obtained from the quadtree decomposition are considered as the initial MCA configurations, and the transition rules are determined using the chaotic map. The performance analyses show that the proposed encryption scheme presents a high immunity against all kind of attacks while maintaining a low complexity, which outcome a notably better performance/complexity trade-off compared to some recently proposed image schemes.

An image encryption scheme combining chaos-memory cellular automata and weighted histogram

This paper presents a new symmetric scheme for enciphering digital images. The proposal is based on the combination of chaos and cellular automata (CA) under the scenarios of one round enciphering/deciphering and permutation–diffusion architecture. All the generated key-streams in the proposed cryptosystem are based on the use of an improved one-dimensional (1D) chaotic system [i.e., logistic–tent system (LTS)] with excellent chaotic properties. These key-streams are related to both the secret key and the characteristics of the plain image. Before applying the encryption process, one pixel of the plain image at a random position is overwritten by inserting the weighted histogram value as a new measure to represent the plain image’s features, this pixel withholds the encryption routine and further will be used to guarantee the resistance to known/chosen plain image attacks (CPA secure). In the confusion phase, a bit-level permutation is adopted with the generated one-time key-streams using an improved 1D chaotic system. This strategy of shuffling is handled in which besides to the modification of each pixel’s position, its value is also changed, to further render the achievement of both confusion and diffusion possible within just this phase. The diffusion phase is divided into two subphases: In the first one, the value of each pixel is changed sequentially by means of an improved one-dimensional chaotic system, to fasten the diffusion process and spread the influence of a single bit over the others, and in the second subphase, two-dimensional reversible memory cellular automata are associated with quadtree decomposition strategy and applied to the output of the first subphase, to enhance both the security and the diffusion effect of the cryptosystem. Security analysis shows the capacity of the proposed scheme to resist the commonly known attacks besides to its competitive speed that traces its suitability for practical image encryption.