9to5 Mac reports that Facebook is currently testing end-to-end encryption for its Messenger app. The feature is called “secret conversation,” and the encryption will be so strong that even Facebook will not be able to access conversations on it.
Apple’s iMessages and FaceTime apps already use end-to-end encryption, as does WhatsApp (as of this past April), but unlike these three examples, Facebook Messenger’s end-to-end encryption can be activated on a chat-by-chat basis.
Facebook also said that secret conversations do not currently support rich content such as GIFs and videos, making payments, and other similar Messenger features. Images will be encrypted in secret conversations, but metadata will not be.
Expect Facebook to make this feature widely available to all Messenger users sometime this summer.
Source: Facebook testing end-to-end encryption in Messenger, branded Secret Conversations