In the present era of digital communication, secure data transfer is a challenging task in the case of open networks. Low-key-strength encryption techniques incur enormous security threats. Therefore, efficient cryptosystems are highly necessary for the fast and secure transmission of multimedia data. In this article, cryptanalysis is performed on an existing encryption scheme designed using elliptic curve cryptography (ECC) and a Hill cipher. The work shows that the scheme is vulnerable to brute force attacks and lacks both Shannon’s primitive operations of cryptography and Kerckchoff’s principle. To circumvent these limitations, an efficient modification to the existing scheme is proposed using an affine Hill cipher in combination with ECC and a 3D chaotic map. The efficiency of the modified scheme is demonstrated through experimental results and numerical simulations.

Security issues are at its peak by the expanding pace of innovation and the utilization of interactive media over the internet. To overcome such security issues, cryptography, steganography and watermarking methods are utilized eventually. In this work, we have fabricated a lossless cryptographic technique for image encryption using random matrix affine cipher (RMAC) associated with the chaotic maps of 2D Hénon (HN) and logistic. The method gives multi-layer security to forestall unauthorized access during transmission over the public networks. This method of encryption is fast with a high throughput of correlated data and works efficiently when compared to some available existing schemes. Numerical simulations and performance analysis insured the security, validation and stalwartness of the presented scheme. Further, the proposed scheme can be efficiently used in practice for secure transmission in wireless applications and small system devices.

This paper proposes an asymmetric encryption scheme for color images by introducing a new efficient triple-layered encryption scheme based on the RSA cryptosystem along with a chaotic map in the discrete Hartley domain. The present approach encrypts the image independently using the RSA cryptosystem and afterward transforms them into discrete Hartley domains to diffuse the image pixels. Further, the pixel positions are dislocated by applying a non-linear chaotic map to provide a complex structure of the scheme. The hardness of prime factorization of integers is intricacy in the RSA algorithm. The massive pixel confusion by a non-linear Hénon map gives rise to an efficient and robust system. Simulation results with performance analysis and the detailed comparison with extant systems assure robustness, validity, and security of the proposed scheme against various cryptanalytic attacks.

The article presents a real-time image encryption using a modified approach of Vigenère cipher and the chaotic maps with an efficient key management. The modification is provided to Vigenère cipher through the key expansion procedure. The proposed encryption chooses four random keys of 8-tuples to expand into the $8\times 8$ initial key block. Thereafter, the Vigenère cipher encrypts the pixels blocks using the initial key block and the next blocks through key updation using the XOR operation and the Arnold transform. Later, the partially encrypted image is further scrambled through the Baker map to increase the randomness and unpredictability of the data. The chosen secret key parameters are exchanged publicly through the Diffie–Hellman key exchange agreement. Simulation results and comparison analysis of some extant systems ensure that the proposed algorithm is secure against cryptanalytic attacks and efficient in real-time image processing. Further, the average execution time for encryption and decryption of an image with size $256\times 256$ is 0.4926 which is very efficient than a typical and recent encryption scheme.

The article presents hyperchaos image encryption using DNA (deoxyribonucleic acid) coding and the chaotic maps in discrete cosine transform. The proposed multilayered security system comprises of advanced levels of confusion and diffusion. Initially, the diffusion among the pixels is attained by employing DNA XOR operation between pixel values and the unpredictable sequence generated from hyperchaotic system. Secondly, the pixels of the partially encrypted image is scrambled by Baker map to permute the image pixels. Finally, the partially encrypted image is diffused through the discrete cosine transform. The significant contribution of this algorithm is to improve the quality of encryption through a DNA encoded scheme. The demonstration results and experimental values are in support the robustness of the proposed scheme and have shown resistance against underlying cryptanalytic attacks.