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.

In the symmetric key cryptography, the purpose of the substitution box is to generate confusion and hence improve the security of the whole cryptosystem. For this reason, many algebraic substitution boxes are constructed depending upon the associative algebras of Galois fields. In this paper, the power associative loop is used for the construction of substitution boxes. This novel structure comprises excellent features which include, the inverse of zero element, non-associativity and fewer constraints as compared to the cyclic group and Galois field. In comparison to existing substitution boxes, the substitution boxes based upon power associative loop are comparatively easy and the above-mentioned properties offer the number of structures to construct highly nonlinear substitution boxes. To obtain the number of substitution boxes, we further applied the symmetric group of order 16 on the proposed substitution box. The evaluation of proposed boxes with different algebraic and statistical analyses like nonlinearity test, strict avalanche criterion, bit independence criterion, linear approximation probability and differential approximation probability indicate the strength of proposed substitution boxes. Majority logic criterion results depict that proposed substitution boxes have better cryptographic strength to apply in different techniques of secure communication.

In this article, we present an encryption technique that can encrypt any digital data. The proposed scheme basically depends on a substitution-permutation network. Two separate bijective maps are used in the proposed algorithm. Firstly, the substitution boxes are used to perform the substitution process. This technique uses elliptic curves (ECs) to create several substitution boxes with good cryptographic properties. The generated substitution boxes are utilized to replace the arrange data that produces the most uncertainty in the plain image data. Further, we used the permutation process to generate strong randomness in the proposed technique. For the evaluation of the stability of the proposed algorithm; nonlinearity, linear approximation probability, bit independence criterion, strict avalanche criterion and differential approximation probability were performed on the substitution boxes. Differential attacks (Number of Changing Pixel Rate (NPCR), Uniform Average Change Intensity (UACI)) and statistical tests (Entropy, Correlation) were performed on the encrypted images to check their resistance against different attacks. The execution and image analysis reveals that the proposed scheme attains good encryption results while requiring minimal computing ability and has efficient potential in real-time image encryption applications.

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.

Gigantic data transfer over networks and internet turned in developing a large number of encryption techniques. As a consequence, in parallel, it gave birth to new plans of attacks. In facet of data security, the algorithms specifically Rijndael (Advanced Encryption Standard-AES), SERPENT and TWOFISH are equally considered to be the best. However, they pay less attention in some cryptographic areas like digital image encryption schemes because of their time consumption inferiority. In this paper, we introduce a time diminishing improved version of SERPENT algorithm depending upon chain ring-based substitution boxes (S-boxes) dealing with 8-bit vector instead of 4-bit. The multiplicative substructures in a chain ring have multiple generators and thus the chain ring based S-boxes improve the algebraic complexity of the cipher. Apart from it, the algorithm is utilized in a digital RGB image encryption application where throughout the chain ring operations are performed. The digital image analyses reveal that the proposed scheme consumes less time (i.e. 8.2 microseconds for encryption and 5.8 microseconds for decryption of a 128-bit block) as compared to the existing prominent RGB image encryption techniques. Furthermore, the investigation on the suggested RGB image encryption scheme it is observed that it has a great resistance against the statistical and the differential attacks.