Secure image encryption using Rubik’s Cube-based scrambling with chaos-driven diffusion and circular shifts

Abstract

The increasing exchange of multimedia content in the digital era demands reliable image encryption techniques to ensure data privacy and security. This paper presents an image encryption method that integrates Rubik’s Cube-inspired scrambling with a chaos-based diffusion process to provide strong security while maintaining computational efficiency. The scrambling stage is implemented using iterative modulo-two operations that determine left or right circular shifts for rows and columns, and these operations are deterministic without the involvement of chaotic sequences in controlling their direction or magnitude. In the diffusion stage, logistic-map-generated keys modify pixel intensity values through XOR operations. Comprehensive security analyses, including entropy, NPCR, UACI, correlation coefficients, SSIM, PSNR, chi-square, and NIST statistical test suite assessments, demonstrate strong cryptographic performance. The proposed method achieves an entropy value of 7.99, an NPCR greater than 0.994, and a UACI greater than 0.32, while the correlation coefficients of the encrypted images approach zero in all orientations. Histogram analysis shows a nearly uniform distribution, and low structural similarity and peak signal-to-noise ratio values confirm strong encryption with accurate decryption. This approach effectively balances implementation simplicity, security strength, and suitability for real-time hardware applications such as FPGA-based systems.