Dual Level Strategy Integrating 2-D CA and DCT Technique for Enhanced Data Protection

In the contemporary era, safeguarding vast amounts of sensitive data and ensuring secure communication are paramount concerns, especially given the prevalence of insecure networks. The fields of cryptography and steganography have emerged as pivotal tools in addressing these challenges, attracting significant scientific attention due to their established effectiveness. This paper proposes a sophisticated double-layered security system for protecting textual data, initially utilizing 2-D Cellular automata (CA) to establish robust encryption protocols. The incorporation of the Von Neumann neighborhood of 2-D CA enhances the generation of secure cryptographic keys, leveraging its complex and chaotic behavior to improve randomness and unpredictability. Subsequently, to enhance security, the discrete cosine transform (DCT) technique is integrated, facilitating discreet embedding of encrypted data into the least significant bit (LSB) of DCT coefficients. An exhaustive range of tests and evaluations, encompassing analysis of key space, complexity, performance metrics, avalanche effect, security attacks, peak signal-to-noise ratio (PSNR) and mean square error (MSE), substantiates the effectiveness and resilience of this multifaceted approach. The findings reveal a significant average avalanche effect of 76%, indicating resilience against cryptographic attacks. Furthermore, superior preservation of image quality is observed during encryption, as evidenced by improved PSNR and MSE values compared to alternative technique. The overall analyses validate the proposed method as a proficient solution for secure data encryption in cyberspace.