Facebook has rolled out a new Secret Conversation feature for its Messenger. This new feature allows users to opt-in for end-to-end encryption of their chat messages. Besides choosing to encrypt their messages, users can also define life-span of their messages.

The new, opt-in feature ensures that only the sender and receiver can read the encrypted messages. Even Facebook would not be able to read the messages. In the wake of recent reports about Yahoo collaborating with US intelligence agencies, the feature is likely to receive a warm welcome from users.

Once a user activates the encrypted chat option, a message pops up saying "Your messages are already secure, but Secret Conversations are encrypted from one device to another." According to Wired, users need to click on the top right-hand corner of the 'new message' screen to access the feature.

End-to-end encryption is already being used by another Facebook chat app, WhatsApp. Both chat apps make use of Signal Protocol for the purpose of encryption. The protocol was developed by Open Whisper Systems, which also operates the Signal messaging app. This is the same protocol which Google used for its Allo app. While WhatsApp and Signal have the default setting of end-to-end encryption, Allo and Secret Conversations both encrypt the messages on an opt-in basis.

Facebook has also announced that its users can send stickers, videos, voice, payments and gif using Secret Conversations. Users can set the messages to expire within five seconds to one day.