Open source
Source code & licences
Relay is built on open-source cryptography rather than anything home-made. Here's what's inside the app, under which licence, and where to find the source.
Relay's source code
Relay's encryption comes from libsignal, which is licensed under the GNU Affero General Public License, version 3 (AGPL-3.0), and Relay itself is released under the same licence.
The complete source — the iPhone app, the relay server and the wire protocol — is public at github.com/CoderDude1232/Relay. Anyone can read it, check what the app really does, and build it themselves.
Found a security problem? Please email security@relaymsg.app or report it privately through GitHub, rather than opening a public issue.
Components
The open-source components shipped in the Relay app. The same list, with copyright notices, is in the app under Privacy → Acknowledgements.
| Component | Licence | What it does in Relay |
|---|---|---|
| libsignal | AGPL-3.0 | The Signal Protocol: PQXDH key exchange, Double Ratchet, sealed sender and safety numbers. © Signal Messenger, LLC. |
| SQLCipher | BSD-3-Clause | The encrypted database on your phone. © Zetetic LLC. Packaged via swift-sqlcipher; includes SQLite, which is in the public domain. |
| swift-protobuf | Apache-2.0 | Encodes messages for the wire. © Apple Inc. |
| swift-sodium / libsodium | ISC | Cryptographic primitives, including those behind blinded contact discovery. © Frank Denis. |
| WebRTC | BSD-3-Clause | Voice and video calls. © The WebRTC project authors. Binary distribution by stasel/WebRTC. |
Questions
Anything about licensing or the source to support@relaymsg.app. Security reports to security@relaymsg.app. For how the pieces fit together, see How Relay works.