We put people first in everything we do at Messenger, and today we are beginning to roll out a new option within Messenger to better support conversations about sensitive topics. Your messages and calls on Messenger already benefit from strong security systems — Messenger uses secure communications channels (just like banking and shopping websites) as well as Facebook’s powerful tools to help block spam and malware. We’ve heard from you that there are times when you want additional safeguards — perhaps when discussing private information like an illness or a health issue with trusted friends and family, or sending financial information to an accountant.
To enable you to do this we are starting to test the ability to create one-to-one secret conversations in Messenger that will be end-to-end encrypted and which can only be read on one device of the person you’re communicating with. That means the messages are intended just for you and the other person — not anyone else, including us. Within a secret conversation, you can also choose to set a timer to control the length of time each message you send remains visible within the conversation. Our technology uses the Signal Protocol developed by Open Whisper Systems. You can read more about the technical details here.