Improved Color Image Encryption using Hybrid Modulus Substitution Cipher and Chaotic Method

Abstract

This study proposes the hybrid substitution cryptography method followed by chaotic methods to improve the security of digital image transactions on the internet. The substitution method used is a hybrid of the modification of the Vigenère and Beaufort cipher algorithm. To do a hybrid, two random keys are used. The first random key is a matrix with 8-bits integer values, while the second random key is a matrix that contains binary values. The modulus operation is used in the main process of substitution methods. In this study, 24-bits true-color images were used as a dataset for the testing experiment. Measurement of encryption quality is measured by Entropy, MSE, PSNR, SSIM, UACI, and NPCR, whereas tic toc functions for measuring the computational time needed. To ensure the decryption process runs perfectly, measuring instruments such as SSIM, MSE, and PSNR are used to compare the decrypted image with the original image, the tic toc function is also used to measure computing performance. Based on the results of testing the quality of image encryption proved to have excellent results where the entropy value is very close to 8, the ideal NPCR and UACI values, as well as excellent visual values based on MSE, PSNR, and SSIM measurements. The image can also be decrypted perfectly with relatively fast computing time in the encryption and decryption process.

Encryption and return method of inspection image of UAV converter station based on chaotic sequence

“…In the formula (2), n represents a qubit parameter, i c is Qubit represent gray value, i represents the pixel position information, and at this time, a random sequence can be generated according to the above quantum protocol. The normalization formula of this sequence () zi is shown in the following (3).…”

“…In the process of power supply and distribution, DC-AC conversion is involved, which affects the operation reliability of the power system. The power conversion [1][2][3] can be effectively carried out through the converter valve and transformer of the perfusion station, which reduces the operation risk of the power system. Therefore, there are more converter stations built in China.…”

Image Encryption using Double Layer Chaos with Dynamic Iteration and Rotation Pattern

“…Several studies have inspired this research in modifying the encryption model, one of which is research [7]. In this research, the encryption method is carried out by combining the chaotic method and the hybrid modulus substitution cipher, both of which are encryption with a chaotic system.…”

“…Several methods for text encryption, such as Advanced Encryption Standard (AES), Data Encryption Standard (DES), 3-DES, and Rivest-Shamir-Adleman (RSA), have been proven to work well on text, but if applied to encryption of images or multimedia data, they are not suitable. Many researchers, such as in research [4][5][6][7][8], state that these methods make the encryption process less efficient, over-complex, and over-computing. Encryption on images is widely applied using the chaos method, which this method has many advantages in encrypting a digital image, some of which are ergodicity characters, sensitivity to more unpredictable initial values, low complexity, and strong correlation, and non-uniform distribution.…”

“…There are many chaotic systems used in image encryption, such as Arnold [5,7], logistic map [12][13][14][15], hyperchaotic [16,17], and others. In many studies of encryption literature on digital images, the use of chaos systems is widely combined with various other encryption methods to improve message security.…”