systemd-ask-password-console.service, systemd-ask-password-console.path, systemd-ask-password-wall.service, systemd-ask-password-wall.path - Query the user for system passwords on the console and via wall
systemd-ask-password-console.service is a system service that queries the user for system passwords (such as hard disk encryption keys and SSL certificate passphrases) on the console. It is intended to be used during boot to ensure proper handling of passwords necessary for boot. systemd-ask-password-wall.service is a system service that informs all logged in users for system passwords via wall(1). It is intended to be used after boot to ensure that users are properly notified.
See the developer documentation  for more information about the system password logic.
Note that these services invoke systemd-tty-ask-password-agent(1) with either the --watch --console or --watch --wall command line parameters.