A Normalized Exponential Piecewise Chaotic System (NEPCS) and DNA Image Cryptography Using SHA-256. - Hammad Safdar Gill; Madiha Amjad; Muhammad Faheem 003; Aqeel Ur Rehman; Umber Rana; Amjad Rehman Khan; Rab Nawaz Bashir (IEEE Access, 2025)