Digital Audio Protection with Confusion and Diffusion Scheme Using Double-Scroll Chaotic Function

Abstract

This article describes a new idea for protecting digital audio with a confusion and diffusion scheme based on the modification of the double-scroll function and SHA-256 function. In the first scheme, the confusion process is carried out by scrambling dual channels of plain audio using the keystream of the double-scroll function in the form of the proposed new nonlinear transformation function. The initial value of the double scroll function is obtained through the SHA-256 function. In the next scheme, the diffusion process is carried out by substituting the value of the dual channels based on the nonlinear transformation function, resulting in cipher audio. The proposed algorithm based on this new idea produces a very large key space of . This means that this algorithm is highly robust to brute force attacks. Simulation of the algorithm based on the test data used produces a histogram of uniformly distributed cipher audio, and the correlation coefficient is negligible (toward zero), which can be interpreted as uncorrelated. This means that this digital audio encryption algorithm is highly resistant to statistical attacks. Another performance resulting from the algorithm in this article is that it is excellent for doing cipher and decrypted audio with reference to the PSNR value of the cipher audio being negligible (4.66037-5.04020 dB), and the PSNR value of the decrypted audio is much greater (69.28398-81.14115 dB).