To protect your encrypted messages from falling into the wrong hands, you can enable the Auto-lock feature in the ProtonMail app.
This feature will prompt users to either enter a 4-digit PIN or to use biometrics to open ProtonMail. You can set your device to automatically lock every time you close your app, or after a set amount of time.
To enable auto-lock, follow these steps:
1. Go to Settings
2. Select Auto Lock
3. Tap on the toggle to enable the feature and then, enter a 4-digit PIN code. Select Create to save your code.
4. Confirm your 4-digit code
Set up the auto-lock timer
Choose for how long ProtonMail can remain unlocked after you stop using the app by selecting Auto-lock timer.
Unlock using biometrics
You can also use your Android device’s face-recognition or fingerprint software to unlock ProtonMail by selecting Unlock using biometrics.
You can use the biometrics feature only after setting up a PIN. Your device’s biometrics system will be used in this case to give you access to the app, instead of the PIN.