FileVault and smart card usage in macOS
Signing in on a Mac with Apple silicon with macOS 11 or later using FileVault allows authentication methods supported by macOS, including built-in support for authentication with CCID and PIV-compatible smart cards.
Universal login with smart card allows a successful FileVault authentication to automatically log into the system as well. FileVault smart card support can be managed using the security command-line tool.
Use password authentication for FileVault and smart card for login
On a Mac with the Apple T2 Security Chip with macOS 10.14 or later, unlocking FileVault enables login. However, FileVault on these computers doesn’t include smart card support. To facilitate smart card login, the following command must be run on each computer:
sudo defaults write /Library/Preferences/com.apple.loginwindow DisableFDEAutoLogin -bool YES
When the Mac restarts, macOS supports FileVault unlock with a password, and then prompts for smart card authentication at the login window. This setting can also be managed using managed preferences in a mobile device management (MDM) solution.
Use recoveryOS to remove smart card linking to FileVault
For a Mac with macOS 11 or later, a smart card recovery option is provided in recoveryOS (if “Enforce smart card” is turned on). In the event that a user’s smart card is lost or damaged, a user can temporarily override smart card enforcement with local administrator authentication. To do this, the user must start their Mac into recoveryOS, authenticate, and then run the following command:
security filevault skip-sc-enforcement <data volume UUID> <operation>
The user is then prompted for an administrator password. If successful, smart card enforcement is skipped for only one login. The user can then unpair and pair a new smart card to resume normal smart card operations.