A robust bit-level image encryption based on Bessel map

A chaotic map plays a critical role in image encryption (IME). The map used to generate chaotic sequences should perform high dynamic characteristics. In this study, a new chaotic system depending on the Bessel function, so-called Bessel map, and a novel Bessel map-based IME scheme are proposed for the IME. The Bessel map has three control parameters, which provide superior ergodicity and diversity. Bessel map has also order degree rather than Sine map, which is used as a control parameter boosting the security. The chaotic characteristic of the Bessel map is verified through different reliable measurements such as bifurcation diagram, trajectory phase, Lyapunov exponent (LE), sample entropy (SE), permutation entropy (PE), and 0-1 test. Then, the Bessel map is employed in a new bitwise IME (BIME) scheme based on bit-level permutation and diffusion processes. The Bessel map-based BIME is validated through various simulated cryptanalyses and cyberattacks as well as compared with the state-of-the-art schemes. The achieved results demonstrate that the BIME based on the Bessel map ensures the most secure ciphered images thanks to the excellent randomness and complexity performance.