The service uses the Signal Protocol developed by Open Whisper Systems. It adds end-to-end encryption to messages making it theoretically impossible for them to be intercepted. Both you and the other person in the secret conversation have a device key that you can use to verify the messages are end-to-end encrypted and you can also set a timer to have your messages disappear from the conversation.

Secret Conversations is an opt-in feature that lets users encrypt their messages so only the people involved in the chat – not Facebook, law enforcement or intelligence agencies – can see the conversation. The fact it is not enabled by default, however, has been criticized by privacy campaigners.

How do I start a secret conversation in Messenger?

To start a secret conversation:

iPhone or iPad:

  1. From Home, tap  in the top right.
  2. Tap Secret in the top right.
  3. Select who you want to message.
  4. If you want, tap  in the text box and set a timer to make the messages disappear.

Android:

  1. From the  tab, open a conversation with the person you want to have secret conversation with
  2. Tap  in the top right of the conversation.
  3. Tap Go to Secret conversation.
  4. If you want, tap  in the text box and set a timer to make the messages disappear.

With secret conversations, you can send:

  1. Messages
  2. Pictures
  3. Stickers
  4. Videos
  5. Voice recordings

Secret conversations don’t support:

  1. Group messages
  2. Gifs
  3. Voice or video calling
  4. Payments

A secret conversation in Messenger is encrypted end-to-end, which means the messages are intended just for you and the other person—not anyone else, including us. Keep in mind that the person you’re messaging could choose to share the conversation with others (ex: a screenshot).

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You can delete all secret conversations on your device at once. Keep in mind that deleting a message or conversation from your device won’t delete it from your friend’s device. You can’t delete sent or received messages from someone else’s device.

To delete all secret conversations from your device:

iPhone or iPad:

  1. From Home, tap your profile picture in the top left.
  2. Scroll down and tap Secret Conversations.
  3. Tap Delete Secret Conversations.
  4. Tap Delete.

Android:

  1. Form Home, tap your profile picture in the top right.
  2. Scroll down and tap Secret Conversations.
  3. Tap Delete All Secret Conversations.
  4. Tap Delete.