Text Encryption using Bi-Amold Cat Map and Modulus Operation

This research proposes an encryption method in text that adopts the chaotic method which is popularly used in 2D matrices such as images. Chaos methods such as Arnold's Cat Map (ACM) have properties of determinism, randomness, sensitivity to initial conditions and ergodicity. In addition, this method also uses permutation, diffusion and confusion models. A slight modification to the text by converting it to binary 8-bits every 8 characters can form a 2-dimensional matrix with a size of 8 x 8, making it easy to perform ACM operations. ACM operation, combined with the substitution method with modulus operation, improves message encryption from various kinds of differential and statistical attacks. The results are proven by several tools such as entropy analysis, avalance effect (AE), and bit error ratio (BER).