Stegcrypt+ :AStegcrypt+ :A Hybrid Cryptographic and Adaptive Steganographic Secure Communication System Hybrid Cryptographic and Adaptive Steganographic Secure Communication System

The rapid growth of digital communication technologies has significantly transformed the way information is exchanged across the world. However, the increasing reliance on online communication platforms has also introduced serious concerns related to data privacy, unauthorized interception, and cyber espionage. Conventional cryptographic techniques are widely used to secure communication channels by transforming readable messages into encrypted ciphertext. Although encryption ensures that unauthorized entities cannot interpret the transmitted information, it does not conceal the presence of sensitive communication itself. The visibility of encrypted traffic may attract attention from attackers and surveillance systems, potentially exposing the communication to further analysis or targeted attacks. To address this challenge, this research proposes StegCrypt+, a hybrid secure communication framework that integrates cryptographic encryption with adaptive steganographic techniques to provide both confidentiality and concealment of information. The proposed system utilizes Advanced Encryption Standard in Galois/Counter Mode (AES-GCM) to perform secure symmetric encryption of messages. AES-GCM provides authenticated encryption, ensuring that the confidentiality, integrity, and authenticity of the transmitted message are preserved. To facilitate secure key exchange between communicating parties, RSA public key cryptography is used to encrypt the symmetric AES key. This ensures that only the intended recipient can decrypt and access the message content. Once the encryption process is completed, the encrypted ciphertext is embedded within digital images using an adaptive Least Significant Bit (LSB) steganography technique. Unlike conventional static embedding methods, the adaptive approach dynamically adjusts the embedding depth according to the complexity and texture characteristics of the cover image. This approach improves payload capacity while maintaining high visual quality and minimizing the possibility of detection through steganalysis.