Jack Dorsey launched bitchat: a messenger for Bluetooth mesh network, it works without the Internet, numbers and servers
Twitter creator Jack Dorsey has revealed what he is working on this weekend - a new messenger called bitchat. It is a decentralised messaging application that works via Bluetooth mesh networks. That means no internet, servers, registrations, or even phone numbers. Only pure encryption and a little magic.
Bitchat features include automatic neighbourhood detection, multi-hop message relay, room chats with passwords, caching and forwarding for offline participants. For privacy, X25519 and AES-256-GCM are used, and for the most paranoid, there is an emergency data deletion function with three taps. The main nuance is that the messenger's performance depends on the number of Bluetooth devices nearby. The more people with Bluetooth enabled and bitchat installed, the better the network.
How bitchat works: the main thing
bitchat is a messenger that does without the Internet and servers, relying solely on Bluetooth mesh networks. Each smartphone in this system acts as a network node: it receives, transmits, and retransmits messages from other users within the Bluetooth range.
- A network without control centres - no servers or clouds. Each participant is both a client and a "repeater". Messages travel from device to device using the multi-hop principle.
- Encryption by default - private messages use X25519 for key exchange and AES-256-GCM for content encryption. Group chats are additionally protected by passwords that are converted into keys using Argon2id.
- No accounts or numbers - the messenger does not require registration, phone or email. Your nickname can be changed on the fly and is not tied to any identifiers.
- Store & Forward - messages are cached for offline participants and delivered when they come online again.
- Emergency wipe - triple-clicking on the logo instantly clears all data on the device.
- IRC-style commands - control the messenger with simple commands: /j to enter the channel, /msg for private chat, /pass to set a password for the room, etc.
- Efficiency - uses LZ4 compression, battery optimisation, and adaptive scanning to save energy.
The app is currently available on iOS and macOS, with an Android version coming soon. The code is open source and available on GitHub, and the system itself looks like an experiment with a decent level of security and privacy.
What is X25519 and AES-256-GCM?
X25519 is a key exchange algorithm based on Curve25519 elliptic curves. It is used to create a shared secret between two parties without directly transmitting this secret. X25519's strengths are speed, compactness, and attack resistance due to its curve design. It is a standard for modern protocols (e.g. TLS 1.3, Signal).
AES-256-GCM is a symmetric encryption algorithm that combines AES with a key length of 256 bits and the Galois/Counter Mode (GCM). GCM provides not only data encryption but also data authentication, which protects against tampering and distortion.
Together, X25519 and AES-256-GCM provide strong end-to-end security: X25519 for key exchange and AES-256-GCM for message encryption.
Who is Jack Dorsey?
Jack Dorsey is an American entrepreneur, programmer, and designer, known as the co-founder of Twitter and the Block (formerly Square) payment service. He was born on 19 November 1976 in St Louis, USA. Back in 2006, he launched Twitter, which has grown to become one of the largest social networks in the world. In 2009, Dorsey founded Square, a mobile payment platform. He is known for his commitment to decentralisation, cryptocurrencies, and a minimalist lifestyle. In 2021, he left the position of Twitter CEO to focus on Block and Web3 projects. He is currently experimenting with open messengers and decentralised services.
Source: GitHub
