Update on May 18, 2017: When we originally announced secret conversations in July of last year, they were available on one device per user. People can now access their secret conversations via multiple devices, for example when they upgrade or lose a device. Sending videos will soon be supported, too.

Originally published on July 8, 2016:

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 in the document linked to below.

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. Secret conversations can only be read on one device and we recognize that experience may not be right for everyone. It’s also important to note that in secret conversations we don’t currently support rich content like GIFs and videos, making payments, or other popular Messenger features.

Secret conversations are available on a limited test basis right now, but we will be making the option more widely available this summer. During this test, we will gather feedback about the functionality, measure performance and introduce tools to enable you to report objectionable content to us. We are putting a lot of thought into the design and implementation of this feature, and we are grateful to the security and privacy experts who have given us their valuable input.