Due to the extensive demand for digital images across all fields, the security of multimedia data over insecure networks is a challenging task. The majority of the existing modern encryption schemes are merely developed that ensure the confidentiality of the image data. This manuscript presents a new image encryption scheme that ensures confidentiality, user authentications, and secure key sharing among the communicating parties. Initially, the users share a secret parameter using Diffie-Hellman over the elliptic curve and pass it through SHA-256. Afterwards, the proposed scheme uses the first 128-bits for the confidentiality of the data, while the remaining 128-bits are for authentication. In the encryption algorithm, the confusion module is achieved by affine power affine transformation. At the same time, the diffusion module is attained through highly nonlinear sequences, which are generated through the elliptic curve. Experimental testing and the latest available security tools are used to verify the effectiveness of the proposed algorithm. The simulation findings and the comparison of the proposed scheme with the existing image encryption techniques reveal that the suggested scheme offers a sufficient degree of security. Furthermore, the outcome of the simulation results divulges several advantages of the proposed scheme, including a large key space, resistance to differential attacks, high efficiency, and strong statistical performance.

The role of substitution boxes is very important in block ciphers. Substitution boxes are utilized to create confusion in the cryptosystem. However, to create both confusion and diffusion in any cryptosystem p-boxes and chaos base substitution boxes are designed. In this work, a simple method is presented that serves both ways. This method is based on composition of the action of symmetric group on Galois field and inversion map. This construction method provides a large number of highly non-linear substitution permutation boxes having the property of confusion as well as diffusion. These substitution permutation boxes have all the cryptography properties. Their utilization in the image encryption application is measured by majority logic criterion. We named these newly designed substitution boxes (S-boxes) as substitution permutation boxes (S-p-boxes), because they serve as both substitution boxes (S-boxes) as well as permutation boxes (p-boxes).

In this manuscript, we propose an image encryption technique by using isomorphic elliptic curves which are proved to be effective against side-channel attacks and have efficient key size as compared to other public-key structures. The proposed technique counts on the Kobltiz method to convert plain images into elliptic curve points. These points are then mapped to the isomorphic curve and are the reason for diffusion in the ciphertext. Besides this diffusion mechanism, elliptic curve points are also involved in the construction of small substitution boxes for confusion. This proposed confusion and diffusion technique also provides quality security in response to well-known cryptographic attacks as established by the number of statistical results and security analysis.

Finite fields are well-studied algebraic structures with enormous efficient properties which have applications in the fields of cryptology and coding theory. In this study, we proposed a lossless binary Galois field extension-based efficient algorithm for digital audio encryption. The proposed architecture hired a special type of curve in the diffusion module which depends on efficient elliptic curve arithmetic operations. So, it generates good quality pseudo-random numbers (PRN) and with slight computational efforts, it produces optimum diffusion in the encrypted audio files. For the confusion module, a novel construction mechanism of block cipher has been employed which includes prominent arithmetic operations of binary Galois field inversion and multiplication operations. The suggested scheme generates multiple substitution boxes (S-boxes) by using a higher-order Galois field. Thus, the replacement with multiple S-boxes generates effective perplexity in the data and provides additional security to the ciphered audio. The investigational outcomes through different analyses and time complexity demonstrated the ability of the technique to counter various attacks. Furthermore, as a consequence of a rapid and simple application of the binary finite field in hardware and software, the proposed scheme is more appropriate to be applied for data security.