Privacy Preserving Reversible Data Embedding In Encrypted Image

Abstract

In The Modern Digital Era, Secure Communication Has Become A Critical Requirement Due To The Rapid Growth Of Cyber Threats, Data Breaches, And Unauthorized Access To Confidential Information. This Paper Presents A Highly Secure Web-based Communication System Developed Using Python Flask And MySQL That Integrates Advanced Cryptographic And Steganographic Techniques To Ensure Multi-layer Protection Of Transmitted Data. The System Enables Authenticated Users To Register, Log In, And Securely Exchange Messages In The Form Of Text Or Files. Unlike Traditional Messaging Systems That Rely Solely On Encryption, This Application Combines AES-GCM (Advanced Encryption Standard – Galois/Counter Mode) Encryption With LSB (Least Significant Bit) Image Steganography To Provide Double-layer Security. In The Proposed System, The User First Encrypts The Message Payload Using AES-GCM Encryption With A Secret Passphrase. AES-GCM Ensures Confidentiality, Integrity, And Authentication By Generating Secure Cryptographic Components Such As Salt, Nonce, Ciphertext, And Authentication Tag. The Encrypted Payload Is Then Embedded Inside A Cover Image Using LSB Steganography, Which Hides The Existence Of The Secret Data By Modifying The Least Significant Bits Of Image Pixels Without Visibly Altering Image Quality. After Embedding, The Generated Stego Image Is Again Encrypted Using AES-GCM Before Being Stored Or Transmitted, Thereby Adding An Additional Security Layer. This Dual Protection Mechanism Prevents Attackers From Detecting Hidden Data Even If The Encrypted File Is Intercepted. Experimental Results Demonstrate That The Proposed System Achieves High Imperceptibility With PSNR Values Exceeding 60 DB And Provides Robust Protection Against Unauthorized Access And Detection Attacks.

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