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

Abstract

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.

Introduction

StegCrypt+ is a hybrid secure communication system designed to enhance data security in modern digital environments. While traditional cryptography (like AES and RSA) protects message content, it does not hide the existence of communication. To address this limitation, StegCrypt+ combines cryptography with steganography, which conceals encrypted messages within digital images, making communication both secure and covert.

The system uses AES-GCM for encrypting messages with authentication and integrity, and RSA for securely exchanging encryption keys. The encrypted data is then embedded into images using an adaptive Least Significant Bit (LSB) technique, which adjusts embedding based on image characteristics to maintain visual quality and avoid detection.

Built on a client–server architecture, the system includes a Flutter-based frontend for user interaction and a Flask-based backend for encryption, embedding, and data processing. Additional modules handle authentication, image analysis, and database management, enabling secure and efficient communication.

Experimental results show that StegCrypt+ maintains high image quality (high PSNR and SSIM, low MSE) while effectively hiding data, making detection difficult. Overall, the system provides a robust, multi-layered security approach, with future scope for AI-based optimization, support for audio/video steganography, and integration of post-quantum cryptography.

Conclusion

This paper presented StegCrypt+, a hybrid secure communication system that combines advanced cryptographic techniques with adaptive steganography to achieve both confidentiality and concealment of sensitive information. The integration of AES-GCM encryption, RSA key exchange, and adaptive Least Significant Bit embedding provides a multi-layered security framework capable of protecting digital communication against interception and analysis. The system architecture, implemented using a Flutter frontend and Flask backend, provides a flexible and user-friendly platform for secure messaging applications. Experimental evaluation demonstrates that the proposed approach maintains high image quality while successfully embedding encrypted data, making it highly resistant to detection. By integrating encryption and steganography into a unified communication framework, StegCrypt+ offers a powerful solution for covert communication in sensitive domains where both secrecy and privacy are essential.

References

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Copyright

Copyright © 2026 Nidhin Dev D, Pavin S Kumar, Rohith Sabu, Sayujya Nandabal, Sulthana S S, Radhika S M. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.