Facebook has finished rolling out end-to-end encryption for users of its Messenger platform, NDTV reported on Tuesday. The social networking giant said all 900 million users of its messaging service can now use the ‘Secret Conversations’ feature in its mobile apps to enable the encryption.

The added layer of security, which first began rolling out in August, will ensure that nobody will be able to read a conversation except the two users participating in it, according to Wired. The company has also included a Snapchat-like feature allowing people to set an expiration time for their messages.

However, users of Messenger will have to enable the feature from within its apps. This is in contrast to Facebook’s other messaging service, WhatsApp, which has enabled the feature by default. The encryption is powered by the Signal platform, developed by Open Whisper Systems.