Hopf-Hopf bifurcation analysis and chaotic delayed-DNA audio encryption using cubic nonlinear optoelectronic oscillator

The study presents a hybrid model for encryption which is based on the utilization of nonlinear chaotic behaviors in a cubic optoelectronic oscillator (OEO) as well as biomimetic DNA computation to achieve secure and lossless protection of audio data. Using a model of the oscillator that had a delayed feedback loop exhibited a strength of dynamical phenomena including Hopf-Hopf bifurcation, quasi-periodicity, and chaos, which will be applied for the generation of cryptographic keys. Bifurcation analysis was performed using the multiple scales method (MMS) in combination with DDE-BIFTOOL, and the analyses were able to observe the dynamical behaviors of the system through bifurcations while mapping high-entropy key sequences. The chaotic key sequences will drive DNA level permutation, substitution, and complementation processes to perform nonlinear diffusion and confusion of the audio data. Statistical tests demonstrated excellent encryption efficacy, with entropy values approaching [Formula: see text], NSCR above [Formula: see text], and UACI around [Formula: see text] confirming adequate randomness and resistance to statistical and differential attacks. In addition, resulting decrypted signals had negligible MSE [Formula: see text] and high PSNR [Formula: see text]dB), ensuring complete lossless recovery and accuracy.