Bit-level image encryption algorithm based on random-time S-Box substitution Mengchen Wang, Hongjun Liu and Mengdi Zhao Eur. Phys. J. Spec. Top., 231 16-17 (2022) 3225-3237 Published online: 04 August 2022 DOI: 10.1140/epjs/s11734-022-00638-y