How to send an encrypted message from your keyboard

Updated September 2026 · ~5 min read

Some things are worth sending and not worth leaving in a group chat. Secret text locks a message with a passphrase before it goes anywhere, from inside the keyboard you already type on — so the chat app carries scrambled text and only the person with the passphrase can read it.

What Secret text does

Type your message as you normally would, tap the AI key, and what lands on your clipboard is a block of characters that looks like this:

🔒PK1.AQFuAwq2xVv0…🔒

Paste that into any chat app, email or note. It is ordinary text, so it travels anywhere text travels. Anyone who sees it without the passphrase sees exactly that and nothing else.

The encryption runs on your phone. Your message is sealed with AES-256, under a key stretched from the passphrase you chose, and the passphrase itself never leaves the device — it lives in the iPhone Keychain or the Android Keystore, and we never receive it. That is what makes encrypted an honest word here rather than a marketing one: there is no copy of your key on our side, so there is nothing for us to hand over, lose or be compelled to read.

Create a passphrase

A keyboard has no field of its own to type into, so passphrases are made in the app rather than on the keys.

1. Open the app and go to Settings Tap the Settings tab, then Enhance key, then Passphrases.
2. Add one Give it a name you will recognise — "Just us", "Work" — and the passphrase itself. The name is what you pick from later; the passphrase is the secret.
3. Choose which one new messages use If you have several, tap Use for new messages on the one you want armed.

You can keep a different passphrase per person. The name is all the keyboard ever shows you, so nothing readable appears on screen when you pick one.

Lock a message and send it

1. Arm the key Hold the AI key, pick Secret text, then choose Encrypt in the row above the keys.
2. Type the message Write it in the chat you are already in, exactly as you would any other message.
3. Tap the key and confirm A card shows what is about to be locked and which passphrase will lock it. Tap Run.
4. Send it The locked version replaces what you typed and is copied for you. Send it, or paste it wherever you need it.

Changed your mind? Undo on the bar above the keys brings your original message straight back.

Unlock one you were sent

1. Copy their message Long-press the message in the chat and copy it. You do not have to trim it — the keyboard finds the locked part inside whatever you copied, including the sender's name and timestamp.
2. Switch the key to Decrypt Hold the AI key, pick Secret text, then Decrypt.
3. Tap the key Pick the passphrase you share with that person and tap Run. The message opens in the keyboard.

If it does not open, the passphrase is the wrong one for that message — try another from the list. Unlocking is free and does not count against any limit.

Sharing the passphrase

This is the part that decides whether any of it is worth doing. The passphrase has to reach the other person somehow, and that route is the weakest point in the whole arrangement.

Say it out loud, use a different app, or agree on one in person. Agree it once and it covers every message you send each other afterwards — you only do this part at the start.

What it does not do

Worth being plain about, because a security feature you have the wrong idea about is worse than none.

• The passphrase is the whole of the protection. A short or guessable one is a weak lock, however strong the encryption behind it. Pick something long and unobvious.
• We cannot recover it. We never receive it, so there is nothing to look up and no reset to send. If you forget it, anything locked with it stays locked.
• It hides the message, not the fact of it. Anyone looking at the chat can see that you sent something locked, and to whom.
• It does not protect an unlocked phone. Someone holding your phone can open the same messages you can, because the passphrase is stored on it.
• Locking needs a connection. It counts as one of your daily AI uses, even though nothing about your message is sent anywhere. Unlocking does not.

FAQ

Can anyone else read a secret message?

Only someone who has the same passphrase. The message is encrypted on your phone before it goes anywhere, so the chat app carries scrambled text and we never see the message or the passphrase. How well it holds depends on the passphrase you pick and on how you share it.

What happens if I forget a passphrase?

Anything locked with it stays locked. We never receive your passphrase, so there is nothing for us to look up and no reset to send you. Write it down somewhere safe before you rely on it.

Does it work offline?

Unlocking does, and it is free. Locking a message counts as one of your daily AI uses, so it needs a connection even though the encryption itself happens on your phone.