A Hybrid Cryptography and Steganography Approach Using RSA and LSB for Secure Message Transmission

Abstract

Information security has become a critical concern in digital communication, requiring robust methods to ensure both confidentiality and imperceptibility. Cryptographic techniques such as RSA effectively protect message content by transforming plaintext into ciphertext; however, the presence of encrypted data may raise suspicion and become a target for attacks. Conversely, steganography conceals the existence of the message but lacks strong protection against extraction if detected. This study proposes a hybrid approach that integrates RSA cryptography with Least Significant Bit (LSB) steganography to enhance secure message transmission. The proposed method first encrypts the secret message using RSA, and subsequently embeds the resulting ciphertext into a digital image using the LSB technique. The system is implemented in Python and evaluated using Mean Square Error (MSE) and Peak Signal-to-Noise Ratio (PSNR) to assess image quality and imperceptibility. Experimental results demonstrate that the proposed method achieves high PSNR values (above 49 dB) and low MSE, indicating minimal visual distortion and high fidelity of the stego image. The integration of RSA and LSB not only secures the message content but also effectively conceals its presence, providing a dual layer of security. Therefore, the proposed hybrid method is suitable for secure digital communication applications requiring both data confidentiality and stealth.