What ILLEST can see, and what it cannot.
Messages, files, voice and the screens you share are encrypted on your device before they leave it. Here is what the server holds, what it is never given, and the limits that remain.
Encryption you can check.
Your device encrypts each message, and only the devices it is for decrypt it. The server stores ciphertext and is never given the keys. Here is what it holds and what it does not.
Sealed on your device
- What your messages say
- Your files, each with a key made for that one file
- Your voice and the screens you share
- Your password: sign-in uses OPAQUE, so it is not sent
- Your wallet's keys
What the server knows
- Who has an account
- Which conversations exist, and who is in them
- When messages are sent, and roughly how big they are
- Your profile, which is public
A group per conversation
Every DM and every channel is its own MLS (RFC 9420) group. Someone joins or leaves, and the keys change.
No plain-text fallback
If a message cannot be encrypted, it is not sent. You are told why.
Keys you can check
If someone's key changes, you are warned, and you can compare safety numbers with them.
Your IP stays yours
Messages, files and calls go through the server. Your device never connects to anyone else's, so they never see your IP address.
What encryption does not cover.
Set out in full, because a claim about privacy is worth only as much as its limits.
What the server still knows, and what this does not protect
- The server knows who has an account, which conversations exist, who is in them, when messages are sent and roughly how big they are. It cannot read what they say.
- In a browser, the page's code comes from the server, so whoever runs the server could change that code to capture your password. The desktop app carries its code inside the app instead of fetching it from the server each time, so it does not have that weakness.
- On the desktop, your device's key is kept in your system keychain and used by the app's own process. The window that draws the screen can ask the app to sign you in or open a message, and is not sent the key. Another program running as you can read the keychain on Windows and Linux, and on macOS the app does not yet ask the keychain to restrict it. One command that moves an older device's key into the app is still present, so this is not yet a promise that no key ever passes through the window.
- Encryption does not protect you from your own computer. Another program running as you can reach what you can.
Come in.
ILLEST opens in your browser. The desktop app is the other way in; what it protects, and what it does not, is set out under Messages. Free to use. Bring your people.