Feature Request: Touch ID Screen Lock (and Android equivalent)

[awensaunders]

Hopefully not a dupe. One of the features I particularly enjoy about Signal is the possibility of setting a screen lock with a timeout that will restrict access to the application even if the phone is unlocked. As keybase is often used to communicate sensitive information much like Signal is, I think this would be a welcome addition.

On iOS, the relevant API is LocalAuthentication from what I can tell.

I haven't really looked for android, but the APIs are probably FingerprintManagerCompat or the newer BiometricPrompt.

If it's easy I might find a few hours and put together a PR. Upvote if you want this feature.

[IpsmLorem]

Duplicate of #17208 ?
it could even secure access to the private key on keychain https://developer.apple.com/documentation/localauthentication/accessing_keychain_items_with_face_id_or_touch_id