Facebook Messenger turns on promised end-to-end chat encryption

Facebook on Tuesday launched end-to-end encryption for all users of its Messenger mobile app, though the option isn't on by default, and comes with some other limitations.

"Secret Conversations" must not only be toggled on in the app's Settings, but manually enabled for each new conversation by tapping "Secret" in the top right corner of the "New Message" screen. Encryption can't be applied retroactively, and both the sender and the receiver must have the latest version of Messenger.

Users also can't send any "rich" content, such as GIFs or personal payments, though stickers, emoji, and photos are available.

The situation is markedly different than with Facebook's own WhatsApp, which offers end-to-end security for all conversations. This may be to ensure people can use chat bots, which by definition requires sending data to remote servers. Data protected with end-to-end encryption can't be intercepted, not even by the company hosting a service.

Facebook has also run into trouble with the technology in Brazil, where WhatsApp has repeatedly been banned by judges demanding data in drug cases. Even though Facebook has noted that it can't supply the requested content, it was even hit with a funding freeze, and the brief arrest of an executive.

Testing of end-to-end encryption in Messenger first began in July.