Looks like a chat, works like a safe
Secret Keeper encrypts your messages and files on your device and produces a self-contained envelope.
Send it through any messenger, email or forum - only the people it is addressed to can read it.
How to get started
1. Install Secret Keeper
It works without servers or accounts: instead of an account, a key created on your device; its public part is your address for messaging.
Create a new key and save the seed phrase: with it the key can always be restored.
2. Exchange addresses with your contact
Send your address through any messenger.
Add your contact’s address to the app: just copy the whole message with the address and open Secret Keeper.
3. Write almost like in a regular chat
The message is encrypted into an envelope: tap Copy or Share and pass it through any channel.
Your contact sees a message like this and can read it in their Secret Keeper.
4. Or chat online!
In messengers with Secret Keeper support everything is automatic: you just write, and envelopes are sealed and opened for you.
Why Secret Keeper
No servers, no accounts
Your address is your public key - sk1…, about 60 characters. No registration, no phone number, nothing stored in a cloud. The whole identity is restored from 12 BIP-39 words.
A self-contained envelope
X25519 key agreement plus XChaCha20-Poly1305. Every envelope carries a key slot for each recipient - and for you, so your own history stays readable. Deliver it over any channel.
Files of any size
Files are encrypted into the .skf container in streaming chunks: a movie encrypts as easily as a note, and truncation or chunk reordering is detected.
Everything stays local
Contacts and history live only on your device. Backup is a single encrypted .skb archive that only your key opens.
If the phone ends up in the wrong hands
The vault is locked with a PIN or biometrics. The rest is designed for pressure, not just for loss.
Wipe on brute force
A configurable number of wrong PIN attempts erases the vault.
Duress PIN
A second PIN that opens an empty profile - or silently wipes the real one.
Clipboard hygiene
Copied secrets are cleared from the clipboard after a timeout.