In macOS 10.13 on APFS volumes that are encrypted with FileVault, there is a new requirement that is needed in order to add a user to the list of authenticated profiles able to unlock the disk. Those users must have a Secure Token. Secure Tokens are generally issued to the first account created on the system, via the Setup Assistant. However, there are other ways to issue a Secure Token to additional user profiles. This Extension Attribute helps you track who has a Secure Token by checking all users on the local system and then generating a comma separated list with their names.