Slock

Two computers... one-bit. A tiny E2E encrypted messenger, tucked inside your capslock key.

Hold Caps Lock on your Mac. A little light comes on on someone else’s keyboard. Let go, and it goes off.

That’s the whole idea. Caps Lock has spent quite enough time shouting. It can have a small, gentle job now.

The firefly is Dit . Dit has one light and considerable enthusiasm.

It’s private by construction. Every message is end-to-end encrypted between your two Macs. There are no accounts, no server that knows who you are, and no analytics. The relay only sees ciphertext and routing.

It’s tiny and open. Two Swift files, no third-party libraries, no Xcode project required. Read the whole thing over a coffee, then build it yourself.

An honest note before you download. slock is an experiment with rough edges. It uses a public MQTT test relay, is not notarized (macOS will ask you to confirm the first launch), and its encryption has no forward secrecy. Keyboard lights also vary by model. Please use it with someone you trust and keep sensitive conversations elsewhere. The security details · What’s been tested

You’ll need two Macs running macOS 13 or newer, an internet connection, and one willing accomplice.