BitChat: A Decentralized Messaging App

Abstract

Secure and private communication has become crucial in today’s era of data breaches, cyber-attacks, and surveillance. This paper presents the design and implementation of BitChat, a blockchain-based decentralized messaging application that ensures anonymous, tamper-proof, and fully encrypted communication. Unlike conventional messaging systems that depend on centralized servers or internet connectivity, BitChat operates on a peer-to-peer decentralized network, allowing communication even during network outages. A comparative study with mainstream messaging platforms like WhatsApp and Telegram highlights differences in privacy, security protocols, and network dependency. The proposed system emphasizes autonomy, resilience, and censorship resistance, offering a secure and reliable communication platform for sensitive and critical environments.

Introduction

BitChat is a decentralized, secure, and offline messaging system designed to overcome the limitations of traditional apps like WhatsApp and Telegram, which rely on centralized servers and internet connectivity. Using Bluetooth Low Energy (BLE) mesh networking, BitChat enables anonymous peer-to-peer communication where every device acts as both a sender and a relay, ensuring connectivity even during outages or censorship.

The platform prioritizes privacy through Curve25519 key exchange, AES-256 encryption, and blockchain-based smart contracts that verify identity and maintain message integrity. It is intended for use in high-surveillance environments, disaster zones, rural regions, and crowded events where internet access is unreliable.

BitChat’s system model includes a user interface layer, application logic, blockchain verification, and strong security mechanisms like SHA-256 hashing and digital identity checks. Messages are encrypted, split into chunks, relayed across the mesh, and logged on the blockchain for tamper-proof verification.

Applications include disaster communication, censorship-resistant messaging, rural connectivity, and communication during large events. While BitChat provides strong privacy and offline capability, it has limitations such as short BLE range, difficulty in discovering users, and reliance on active relay nodes.

Future improvements include Wi-Fi Direct support for better range, enhanced verification, UI simplification, and broader adoption through open-source collaboration.

Conclusion

We presented BitChat, a decentralized, privacy-focused messaging application that enables secure communication without internet using Bluetooth mesh and store-and-forward mechanisms. It ensures anonymity, security, and censorship resistance through strong encryption, decentralized identity management, and privacy features like disappearing messages and panic wipe. While still evolving, BitChat demonstrates how smartphones can form resilient offline networks for emergencies, protests, and remote areas—marking a step toward self-sovereign, secure communication in the digital era.

References

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Copyright

Copyright © 2025 Anushka Vinod Patil, Prof. Pallavi A. Chaudhari. 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.