Optimized Digital Audio Scheme Using 4D Lorenz Hyperchaotic System, FAN Transform, and ABC Optimization

Abstract

A significant amount of data is transmitted globally in audio format, making audio security increasingly important. Audio encryption is thus essential for protecting sensitive data from unauthorized access and modern security threats. This research proposes a hybrid encryption framework that combines the Fast Approximation of Nonlinear (FAN) Transform with the Artificial Bee Colony (ABC) optimization algorithm. Initially, the input signal is converted into a 256 × 256 two-dimensional matrix and normalized to prepare it for encryption. Finally, the Artificial Bee Colony algorithm is utilized to perform an additional scrambling phase, searching for an optimal permutation that minimizes the correlation between adjacent signal elements. The novelty of the proposed scheme lies in jointly integrating these four components into a single encryption pipeline; the FAN transform, coupled with the 4D Lorenz hyperchaotic system, provides high-complexity spatial permutation. This multilayered encryption approach ensures high security by combining chaos theory, bio-inspired computing, and evolutionary optimization. Experimental results indicate an average value for correlation coefficient of 0.000002, several Pixels Change Rate (NPCR) of 99.59%, a Unified Average Changing Intensity (UACI) of 26.06%, a Peak Signal-to-Noise Ratio (PSNR) of 10.30874, a Mean Squared Error (MSE) of 6069.17, a Signal-to-Noise Ratio (SNR) of 3.673422, the entropy of 7.996856 and the Log-Likelihood Ratio (LLR) of 4.9577.