NOMAN AKHTAR2025-09-272025-09-272020https://escholar.umt.edu.pk/handle/123456789/7237Modern block cryptosystems are used to enhance the security of confidential data and message transmission channels. For this purpose, different substitution and permutation processes are executed. S-boxes are used to perform substitution operations in different block cryptosystems. The main objective of S-box is to create nonlinearity, distraction and resistant against various cryptanalysis. Many researchers have introduced complex algorithms to generate different S-boxes. In this research, an innovative method is proposed to generate dynamic and key dependent substitution boxes based on cubic chaotic map. The method of S-box is very modest and better in strength than other S-boxes. Statistical analyses are performed on standard properties such as; Differential Uniformity, Strict Avalanche Criterion, Nonlinearity, Linear Probability, and Bit Independence Criterion in order to measure the strength of proposed S-box. Comparative analysis of proposed outcomes with other S-boxes validates that designed S-box is worthwhile for use in modern encryption applications.enThesis