Post Quantum Steganographic Cryptography (PQSC)

Abstract

The rapid growth of quantum computing poses a significant threat to traditional cryptographic systems, such as RSA and ECC, which are widely used to protect sensitive information in various sectors, including finance, healthcare, and government. These methods rely on mathematical problems that quantum computers could solve far more quickly, raising concerns that encrypted data may soon become vulnerable. At the same time, traditional steganography is becoming easier to detect due to the improvement of analysis tools, making it harder to hide secret communication effectively. This project addresses these challenges by combining post- quantum cryptography with steganography to enhance data security and secrecy. To solve this problem, the project designs and implements a Post-Quantum Cryptographic Steganography (PQCS) system. It utilises Kyber512, a lattice-based encryption method resistant to quantum attacks, in conjunction with AES256 encryption for enhanced protection. The encrypted message is then hidden inside a PNG image using Least Significant Bit (LSB) steganography, allowing covert communication while keeping the image visually unchanged. The system also includes basic logging to monitor key events during encryption and embedding, and follows a modular, procedural design for simplicity and cross-platform compatibility. Initial tests indicate that the prototype can successfully encrypt, embed, and recover secret messages without altering the carrier images visibly. The Peak Signal-to-Noise Ratio (PSNR) was measured at 76.40 dB, and the Structural Similarity Index (SSIM) was 1.0000, indicating excellent visual fidelity between the original and stego images. Additionally, both the encoding and decoding processes were completed in under 30 seconds, confirming the system’s efficiency. These results demonstrate that merging post-quantum cryptography with steganography is a promising approach for building secure communication systems that can withstand emerging quantum threats.