Facebook today began a test program rolling out opt-in end-to-end encryption for its Messenger service called Secret Conversations.
The end-to-end encryption is based on the Signal protocol developed by Open Whisper Systems, the same protocol that stands up the crypto in the Signal and WhatsApp messaging applications.
The Facebook version of the encryption service is not on by default and is available only on one device at a time.
“Starting a secret conversation with someone is optional. That’s because many people want Messenger to work when you switch between devices, such as a tablet, desktop computer or phone,” Facebook said in its announcement. “Secret conversations can only be read on one device and we recognize that experience may not be right for everyone.”