An audio encryption algorithm based on a non-degenerate 2D integer domain hyper chaotic map over GF(2ⁿ)

To ensure the security transmission of audio signals in instant messaging tools, a chaos-based dual-channel one-time one-key audio encryption scheme was proposed. First, a non-degenerate 2D integer domain hyper chaotic map (2D-IDHCM) over GF(2ⁿ) was constructed, the results of dynamics analysis showed that the 2D-IDHCM has ergodicity and large Lyapunov exponents. Then, based on 2D-IDHCM, two keyed strong S-Boxes were constructed. Further, an audio encryption & decryption algorithm was designed using 2D-IDHCM and keyed strong S-Boxes. The novelty includes: (1) 2D-IDHCM has no dynamic degradation, fast iteration speed and no need for data type conversion, which improves the efficiency of the algorithm. (2) The algorithm includes confusion process and diffusion process, which are resistant to most common attacks. Experimental results and security analysis demonstrated that the algorithm is sensitive to the initial condition, reduces the correlation of the original audio, and the total key space can reach 2²²⁴. In addition, NPCR and UACI are all close to their ideal values of 99.6094070% and 33.4635070%, and the information entropy is close to the ideal value of 8.