Labs · Encryption
Encrypted messages, end to end.
Type a message and watch it become something the server can hold but not read.
Send a message below, then switch the view to the server. Same conversation, same bubbles, no words. It all runs in your browser and nothing is sent anywhere.
Danny
End-to-end encrypted
Sealing the thread…
Every message is sealed in this tab as you send it. Nothing is sent anywhere.
Step by step
What happens to a message on the way.
The same six steps every message takes, slowed down.
Sealed in this tab · nothing is sent
AES-GCM · 256-bit
You send
Meet at the ground at 7. Bring the good ball.
What the server holds
Nothing yet.
They read
Waiting.
Plain words, sitting on your own device.
shared key · … …
one-time number · … …
Send the same message again without changing a word: the sealed version comes out completely different. Every message is locked with its own one-time number, so two identical messages never look alike and nobody can build a dictionary of what a given block of gibberish means.
The key exchange
How both ends get the key without sending it.
01
Every device makes a pair of keys
One private, one public. The private key is generated on the phone and stays there. It is never uploaded, and we could not hand it over if we were asked.
02
The public key goes to the server
That half is meant to be seen. It lets anyone seal a message that only the matching private key can open, without the two devices ever having met.
03
The message is sealed before it leaves
Encryption happens on the device, not on the way. What travels, and what the server stores, is already sealed.
Keys also move forward. Each message advances the chain, and the old key is thrown away, so a key taken today will not open what was said last week. If someone leaves a group, the remaining members re-key and the leaver reads nothing further.
Where it stands
What a server can hold, and what it cannot.
It holds
- Public keys
- Sealed messages it cannot open
- Who is in a conversation, and when it was busy
It never has
- The words in any message
- Private keys, which never leave the device
- A way to read yesterday's messages with today's key
We built this for a group chat inside a football app, where the messages are ordinary and the point is that they are nobody else's business. The same shape suits anything with a duty of care attached to it.
Talk to us about yours