

All phones have a BFU (before first unlock) state, and GrapheneOS doesn’t require a passphrase unless you’ve set one, otherwise it’s your PIN. Fingerprint unlock is disabled until after BFU though, so it requires essentially using a backup PIN even if you always use your fingerprint, at least for first unlock.
To add to the security of the PIN and to prevent reading screen smudges you can enable an option so that the digits on the PIN pad are randomized each time it loads.
Graphene also supports fully isolated user accounts. Applications running in one profile can not even discover the existence of the other profiles*. There is a way to forward notifications from user containers but is disabled by default. Each account, when inactive, is encrypted independently of the system drives and the key is generated at user login with the entry of a password and overwritten in memory upon logout.
*If you enable the notification forwarding, a hostile application running on the primary account could deduce that there is at least one other user profile on the phone by analyzing the notifications.






That’s only a tiny, tiny piece of it. If you want to know more: https://grapheneos.org/features