A new cryptographic method for image encryption

In the last decade, the communication of images through the internet has increased. Due to the growing demands for data transfer through images, protection of data and safe communication is very important. For this purpose, many encryption techniques have been designed and developed. New and secured encryption schemes based on chaos theory have introduced methods for secure as well as fast communication. A modified image encryption process is proposed in this work with chaotic maps and orthogonal matrix in Hill cipher. Image encryption involves three phases. In the first phase, a chaotic Henon map is used for permuting the digital image. In the second phase, a Hill cipher is used whose encryption key is generated by an orthogonal matrix which further is produced from the equation of the plane. In the third phase, a sequence is generated by a chaotic tent map which is later XORed. Chaotic maps play an important role in the encryption process. To deal with the issues of fast and highly secured image processing, the prominent properties of non-periodical movement and non-convergence of chaotic theory play an important role. The proposed scheme is resistant to different attacks on the cipher image. Different tests have been applied to evaluate the proposed technique. The results of the tests such as key space analysis, key sensitivity analysis, and information entropy, histogram correlation of the adjacent pixels, number of pixel change rate (NPCR), peak signal to noise ratio (PSNR), and unified average changing intensity (UCAI) showed that our proposed scheme is an efficient encryption technique. The proposed approach is also compared with some state-of-the-art image encryption techniques. In the view of statistical analysis, we claim that our proposed encryption algorithm is secured.

Optimized Chaotic encrypted image based on continuous raster scan method

The main purpose of the proposed image encryption (IE) method is to enhance various security characteristics to protect sensitive images on the internet. In the literature, chaotic maps are preferred for image encryption because of their high randomness and sensitivity to initial parameter values. Therefore, metaheuristic algorithms have been utilized to fine-tune the parameters. In this research, we have employed the metaheuristic Lyrebird optimization (LO) algorithm to fine-tune the chaotic map parameters. The LO algorithm is chosen over other algorithms due to its better exploration and exploitation rate to search for the best solution. The LO algorithm searches for the best parameter value based on the objective function. This research involves the formulation of a multi-objective function that incorporates numerous security parameters, namely, entropy and correlation coefficient (CC), to improve the security attributes of the IE model. The proposed IE model has two steps. In the first step, a random key is generated to transform the pixels of the secret image, whereas in the second step, the image pixels are shuffled based on the shuffling index values to reduce the correlation among the neighboring pixels. In both steps, we have used the chaotic logistic map. The proposed IE is evaluated against statistical and differential attacks on the standard dataset by considering the various images and their different resolutions. The uniform distribution of the histogram of the encrypted images is validated using the chi-square test. Besides that, entropy analysis shows that the average entropy value is 7.9973, 7.9993, and 7.9998 for 256x256, 512x512, and 1024x1024 image resolutions. The average CC and SSIM are near zero value. The average NPCR value (>0.9969) is near the 1 value. Finally, the comparative analysis based on entropy, CC, and NPCR parameters shows that the proposed IE model outperforms the existing models.

A robust and secure chaotic standard map based pseudorandom permutation-substitution scheme for image encryption

Image encryption based on chaotic maps is an important method for ensuring the secure communication of digital multimedia on the Internet. To improve the encryption performance and security of image encryption systems, a new image encryption algorithm is proposed that employs a compound chaotic map and random cyclic shift. First, a new hybrid chaotic system is designed by coupling logistic, ICMIC, Tent, and Chebyshev (HLITC) maps. Comparison tests with previous chaotic maps in terms of chaotic trajectory, Lyapunov exponent, and approximate entropy illustrate that the new hybrid chaotic map has better chaotic performance. Then, the proposed HLITC chaotic system and spiral transformation are used to develop a new chaotic image encryption scheme using the double permutation strategy. The new HLITC chaotic system is used to generate key sequences used in the image scrambling and diffusion stages. The spiral transformation controlled by the chaotic sequence is used to scramble the pixels of the plaintext image, while the XOR operation based on a chaotic map is used for pixel diffusion. Extensive experiments on statistical analysis, key sensitivity, and key space analysis were conducted. Experimental results show that the proposed encryption scheme has good robustness against brute-force attacks, statistical attacks, and differential attacks and is more effective than many existing chaotic image encryption algorithms.

Due to easy and simple implementation, normally single 1-D chaotic maps like logistic and sine maps are employed in multimedia data encryption. However, data encrypted through a single chaotic map does not provide better security in terms of resistance against various attacks. In this paper, 2D Henon chaotic map and skew tent map are deployed in the design of an efficient chaos-based image encryption algorithm. To confuse the relationship between plaintext and ciphertext images, both chaotic maps play a key role in the permutation and diffusion mechanism. In the confusion stage, firstly, the Henon chaotic map generates two different chaotic sequences, which are further applied in row and column permutation of plaintext image. The pixel values diffusion is produced by unimodal skew tent map via XOR operations. In the last stage of encryption algorithm, Hussain's substitution box is used to substitute each pixel into a new random pixel. Extensive security analysis and resistance to statistical attack prove the security of anticipated scheme.

The rapid growth of online information transmission has made the secure transmission and storage of sensitive visual information crucial, particularly in light of the continuous increase in cyber threats. Traditional encryption algorithms are not very effective on images due to their very high pixel correlation, larger file sizes, and intrinsic redundancy. This paper presents a new framework of secure image encryption that will make use of advanced chaotic maps and cellular automata dynamics. It creates deterministic randomness, high sensitivity to initial conditions, and unpredictability through chaotic maps. CA introduces a series of dynamic, rule-based transformations that ensure robust properties for diffusion and confusion. During encryption, chaotic maps create pseudo-random sequences that control both the CA-based pixel scrambling and value transformation. This provides a very secure encryption method with many layers. It ensures high entropy in key generation, resistance against brute-force attacks, and high sensitivity to initial parameters. The scheme works because it can withstand differential, statistical, and noise-based attacks and show performance metrics like entropy analysis, correlation coefficients, histogram uniformity, and robustness. The suggested method is characterized by large-scale use, adaptability, and safety from modern cryptographic threats.

Image encryption algorithm based on the finite fields in chaotic maps

The paper introduces an efficient asymmetric algorithm for encrypting images utilizing chaotic maps and elliptic curve cryptography. In the proposed image encryption method, there is a combination of elliptic curve ElGamal encryption method with masking of image through chaotic map for enhancing security and efficiency. The proposed algorithm can encrypt images of any size. Security analysis is carried through to validate efficiency, sturdiness and feasibility of the algorithm. Compare to recent related encryption schemes, this scheme has better ability to resist crypt analytical and statistical attacks.

An image encryption scheme based on new spatiotemporal chaos

Audio data are used in various fields such as education, engineering, mathematics, art, advertisement, military, medicine, scientific research, and many more. This excessive growth of audio data boosts the importance of multimedia data processing tools and digital documentation. This access to multimedia data through the internet has created inappropriate prospects which are hazardous for the confidentiality and integrity of the data. To encounter these threats, the domain of audio data security gains broad attention. A considerable number of algorithms have been established to protect personal information over open networks. Finite fields are well-studied algebraic structures with enormous efficient properties which have applications in the fields of cryptology and coding theory. Here, an existing system uses lossless binary Galois field extension based efficient algorithm for audio data encryption. The architecture hired a special type of curve in the diffusion module which depends on efficient elliptic curve arithmetic operations. So, it generates pseudo-random numbers (PRN) and with slight computational efforts, it produces optimum diffusion in the encrypted multimedia files. The method is compared with the proposed system using a scheme uses Henon chaotic map and 128-bit AES secret key in order to generate the cipher audio data. Henon chaotic map is a two dimensional iterated discrete dynamic system that shows chaotic character on specific values of the constants used. Chaotic maps are very sensitive to the initial parameters, i.e., a slight change in the initial conditions drastically changes the overall output generated by the chaotic system. The investigational outcomes through different analyses and time complexity demonstrated the ability of the techniques to counter various attacks. Furthermore, two schemes are compared and more appropriate to be applied for data security.

This paper proposes a novel image block encryption algorithm based on three-dimensional Chen chaotic dynamical system. The algorithm works on 32-bit image blocks with a 192-bit secret key. The idea is that the key is employed to drive the Chen’s system to generate a chaotic sequence that is inputted to a specially designed function G, in which we use new 8x8 S-boxes generated by chaotic maps (Tang, 2005). In order to improve the robustness against differental cryptanalysis and produce desirable avalanche effect, the function G is iteratively performed several times and its last outputs serve as the keystreams to encrypt the original image block. The design of the encryption algorithm is described along with security analyses. The results from key space analysis, differential attack analysis, and information entropy analysis, correlation analysis of two adjacent pixels prove that the proposed algorithm can resist cryptanalytic, statistical and brute force attacks, and achieve a higher level of security. The algorithm can be employed to realize the security cryptosystems over the Internet.

In this paper, a new algorithm for designing one-way cryptographic hash function using chaotic Chirikov map is proposed. High sensitivity of Chirikov system makes it an ideal candidate for secure hash function design. In the proposed algorithm, the input message is split into a number of small blocks. The blocks are processed using chaotic map. The two intermediate hashes are generated using evolved control and input parameters. The two intermediate hash values are then employed to yield the final variable-length hash. The simulation and statistical analyses illustrate that the anticipated hash algorithm exhibits encouraging lineaments like high sensitivity to input messages and key, satisfactory confusion and diffusion attributes which verify the suitableness of proposed algorithm for the design of secure cryptographic variable-length hash functions.

Image encryption with compound chaotic sequence cipher shifting dynamically

An encryption method is proposed that uses self-invertible matrix, modular function, Non-Linear shift register and the chaotic map known as Logistic. Parameter of Logistic map act as secret key. As chaotic system used in this algorithm is 1-D system, the key space is lesser than 2100 which shows that the method is weak against Brute-force attack but identifiability property of the selected key from key space assures its strength against the attack. Key sensitivity and plaintext sensitivity of the key chosen from key space for the algorithm is analyzed and its strength against known-plaintext attack is also tested and conclusions are derived.