Facebook turned to biometrics to add a new layer of security for its Messenger app, unveiling a feature which uses a device’s fingerprint and face scanning capabilities to protect private exchanges.

The App Lock tool offers users the ability to hide their messages behind a lock screen, making them accessible only through the use of touch or face ID. Facebook claimed this is accomplished without biometric data being transmitted to, or stored by, the company.

In a blog, director of product management for Messenger privacy and safety Jay Sullivan said the tool gives users “the confidence to know that if a friend or family member needs to borrow your phone, they won’t be able to access your chats”.

He added users can activate or disable App Lock through a new privacy settings menu for Messenger, which also offers control of who can view or access accounts.

App Lock is initially available on iOS devices with Android compatibility due “in the next few months”.

Sullivan said the company is developing additional privacy tools which will allow users to control who can message or call them directly. It also plans to test a feature akin to one offered on Instagram and WhatsApp which blurs images included in messages sent from unfamiliar users.