Questions and answers

Secret chats are currently available in the DiiL app for Android. The iPhone app has regular (cloud) chats and end-to-end encrypted one-to-one calls.

What is a secret chat, and how is it different from a regular chat?

A regular chat (and every group and channel) is stored on our servers, like a cloud chat in Telegram. That is why it is on all your devices and you can find your history after you sign in on a new phone. Messages are encrypted on the way between your phone and our servers, but they are not end-to-end encrypted: our servers can read them.

A secret chat is end-to-end encrypted. Messages and files are encrypted on your phone and can only be decrypted on the other person's phone. We cannot read them, and our servers keep the encrypted messages only until they are delivered. Secret chats also have a self-destruct timer, and notifications about them never show the sender or the text.

To start one, open the person's profile, tap ⋯, then Start secret chat (Android). The other person accepts the invitation, and the chat opens.

Why is a secret chat only on one device?

The keys that encrypt a secret chat are created on your phone and never leave it. Your other devices don't have those keys, so they cannot read the chat, and we cannot copy it to them, because we don't have the keys either.

This means:

• a secret chat is between one device of each person;
• it doesn't appear on your other phones or tablets;
• if you sign out, reinstall the app or lose your phone, the secret chats on it and their history are gone for good. Start a new secret chat when you need one.

Secret chats are not included in cloud backups. There are no secret group chats.

How do I check the encryption keys?

Checking the keys proves that nobody is secretly sitting between you and the other person.

1. Open the secret chat and tap ⋯ → Encryption key.
2. You see six emoji and a number. They are calculated from the keys of both phones.
3. Compare them with the other person: in person, or in a call.
4. If they are exactly the same, tap They match. The chat is marked Verified on your phone.

If they are different, don't send anything sensitive in that chat. Close it and start a new one.

What do the four emoji in a call mean?

During a one-to-one call you see a lock and four emoji at the top of the call screen. They are calculated from the encryption keys of both phones.

Ask the other person which emoji they see. If they are the same, the call is end-to-end encrypted and nobody has got in the middle, not even our servers. If they were different, someone would be interfering with the connection: end the call.

Tap the emoji to see this explanation in the app.

Are group calls end-to-end encrypted?

No. Group calls go through our media server, which forwards each person's audio, video and screen to the others. They are encrypted on the way, but the media server processes them. We do not record calls. One-to-one calls are end-to-end encrypted.

Can DiiL read my messages?

Our servers can technically read regular chats, groups and channels, because they are stored there so you can use them on all your devices. Our staff have no access to your chats; moderators see only the messages someone reported. We cannot read secret chats.

The full details are in our Privacy Policy.