Enhanced DFT-Based Chaotic Image Block Cipher with Several Modes of Operation

Chaotic image encryption has been investigated extensively in the literature in different domains, including the frequency domain using Discrete Fourier Transform (DFT). Despite DFT-based chaotic image cryptosystems exhibiting good confusion properties, they suffer from poor diffusion characteristics and non-uniform histograms. Therefore, they are vulnerable to many attacks, such as differential attacks, and statistical cryptanalytic attacks. This paper presents an enhanced block cipher image cryptosystem with several modes of operation based on the concept of bit reversal using the 2D chaotic Baker map and DFT. The proposed enhancement develops an improved image encryption scheme that involves properly diffusion-confusion enhanced operations within modified versions of the known block cipher modes of operation, namely Cipher Block Chaining Mode (CBC), Cipher Feedback Mode (CFB), and Output Feedback Mode (OFB). These enhanced operations are based on a 2D chaotic baker map in the Fourier domain. The proposed enhancement is validated using a MATLAB simulation. Results show that the proposed work manages to overcome the abovementioned problems outstandingly and outperforms the existing results in the literature in many encryption quality metrics.