WhatsApp is Facebook’s most secure chat app because it offers end-to-end encryption on all communications by default. In the future, Facebook plans to create a unified messaging system that would work across Messenger, WhatsApp, and Instagram, complete with end-to-end encryption. But until then, Facebook just added a new security feature to the iPhone version of its most popular messaging app, support for biometric authentication. In other words, you’ll finally be able to protect your WhatsApp chats with Face ID or Touch ID on iPhones and iPads.

If you were worried about others accessing your WhatsApp activity, especially on devices that you might share with children or friends, then all you have to do to secure those chats is to update the WhatsApp to the newest version. Once that’s done, open the app and head to Settings, Account, Privacy, and then Screen Lock. In there, you have the option to turn on Face ID or Touch ID for the app.

When enabled, the feature will still let you reply to messages from notifications and answer calls if the app is locked, as Facebook explains right inside the app. But if you want to access anything else in the app, you’ll have to use your finger or face to unlock it.

There’s no password backup option, which means that only your fingerprint or face will unlock the app. So you’ll need actual access to the device to open the chats. Also, the desktop companion app doesn’t have the same extra layer of security. So, in theory, anyone with access to your computer could still read your WhatsApp messages.

Also of note, the Android version of the app doesn’t support biometric authentication at this time. While just a few Android handsets out there feature 3D facial recognition support like the iPhone, all of them have fingerprint sensors, which means WhatsApp for Android can and should receive this feature in the near future.