• P. Swati
• Aditi Kumari
• Leesa Sinha
• Aayush Chandravanshi

This research presents HackShield, a mobile-based security application that combines steganography and blockchain-inspired verification to securely encode and share sensitive information. The system leverages Least Significant Bit (LSB) steganography to embed encrypted payloads—such as confidential messages—within image files, ensuring that the existence of the message remains hidden from unintended recipients. Each payload is bundled with metadata including a recipient ID, sender’s device ID, timestamp, and a unique SHA-256 hash to maintain data integrity. This structure is then stored and tracked, mimicking the append-only nature of blockchain without incurring its computational complexity. The application is built using React Native and Expo, offering a modern, responsive user interface. After encoding, the system saves the stego-image locally and provides users with a secure option to share the image via file/document mode to prevent compression. A custom “Block Explorer” tab mimics blockchain interfaces by listing mined blocks with hash IDs, sender, recipient, and verification status. The decode module verifies device authorization by comparing device hashes and validates the data’s integrity using the embedded hash and database-stored blocks. The system aims to offer a privacy-preserving communication framework for secure data sharing, suitable for use cases like whistleblowing, secure ID transfer, and encrypted record-keeping. This hybrid approach bridges the usability of mobile apps with principles inspired by blockchain and cryptography, offering a novel, lightweight alternative to traditional secure communication platforms.

Steganography, Blockchain, Secure Communication, Device ID Verification, LSB Encoding, SHA-256 Hash, React Native, Flask API, MongoDB, Tamper-Proof Messaging

"HACKSHEILD- Blockchain Based Message Encryption App", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.12, Issue 4, page no.n430-n440, April-2025, Available :http://www.jetir.org/papers/JETIR2504D53.pdf

"HACKSHEILD- Blockchain Based Message Encryption App", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.12, Issue 4, page no. ppn430-n440, April-2025, Available at : http://www.jetir.org/papers/JETIR2504D53.pdf