Hollow - native desktop app, signed messages, full E2EE (Olm+MLS+SFrame), zero accounts, only local data and MORE
Hey everyone! I want to introduce you to Hollow, a completely different chatting app from anything else on the market. For a full project overview, I HIGHLY RECOMMEND watching my YT video here: https://youtu.be/qsXc-hJizsQ I explain literally everything the project has to offer in (almost) simple words, but I'll list some stuff here too.
The app is native because it's written in Flutter (Dart) and Rust, so it's compiled and doesn't have any runtimes like Node.js or Electron. An account in Hollow is just your Ed25519 key with Bip-39 mnemonic (24 words like crypto wallets) and you can export your entire identity with data into a simple .hollow file and import on first app launch.
Hollow is fully distributed, which means that members collectively host ALL data within their servers. The owner cannot destroy any messages because they're automatically synced using CRDTs and saved between people in their own locally stored, encrypted SQLite database (only you with your key have access to it). I went even further because all messages are cryptographically signed with your key, so nobody can fake messages with stupid screenshots. You can easily check if the signature is correct using the built-in tool under the Security tab in Settings.
Direct Messages are encrypted with Olm (Double Ratchet, same protocol as Matrix), servers use MLS (RFC 9420; the most modern protocol for scaling in large servers; Matrix doesn't even have it fully implemented yet), all audio/video/screen sharing is encrypted with SFrame (also a modern protocol, but specifically for media - RFC 9605). Again, it's ALREADY implemented in Hollow!
You might wonder... How are messages exchanged? My open-source relay server is the only infrastructure (stores nothing, sees only encrypted noise) that handles simple WebSocket connections. It uses uWebSockets (C++), so my ~$8/mo VPS can easily handle up to *~572k connections!* I rewrote it from Rust to C++, so this is probably one of the cheapest $/user/mo float any messaging app can have. TLS is terminated at the relay, so network observers can't see metadata like who's talking to whom or message timing.
The app is in public alpha release. Currently only on Windows, with MacOS/Linux support coming soon. You can download it for free from my website https://anonlisten.com/ Auto-updater is included!
A third-party security audit is planned before the actual release (specifically the OTF Security Lab, you can google it). If you have questions, then don't hesitate to ask. I'll answer everything! Thank you so much for reading and take care!
Relay repo: https://github.com/VitalikPro13/hollow-relay
Technical Whitepaper: https://github.com/VitalikPro13/hollow-relay/blob/main/WHITEPAPER.md
*raw connections, not counting TURN fallback.