Hybrid audio encryption method based on DCT and Walsh-Hadamard transform using Henon chaotic maps and logistic maps

A new hybrid audio signal encryption algorithmis proposed, combining transform-domain processing using thediscrete cosine transform (DCT) and the Walsh–Hadamardtransform (WHT) with the application of Henon chaotic mapsand the logistic map. The novelty of the method lies in theintegration of DCT–WHT transforms to enhance decorrelationand energy compaction, as well as in an adaptive key selfgenerationmechanism based on the statistical characteristicsof each audio frame, which eliminates the need for transmittingand storing external secret data. The algorithm reducesthe correlation between the original and encrypted signals toapproximately 0.0006 (compared to approximately 0.00045 forthe H´enon+LWT method), increases entropy to 5.18 bits (animprovement of approximately 8.3%), provides NPCR approximately97.63% (versus 98.47%) and UACI approximately 6.67%(versus 15.57%), with RMSE of reconstruction 0.0205 (versus0.0354). Experiments were conducted on the VCTK corpus (16kHz, 16-bit, 1000 audio segments). In addition to describing theproposed method, the paper also contains a detailed comparativeanalysis of its performance relative to other approaches, includingDCT+H´enon, WHT+H´enon, and H´enon+LWT algorithms. Sucha comparison allows an objective assessment of the advantagesand limitations of each method in the context of cryptographicsecurity, reconstruction quality, and computational load.