Login and keychain authentication

macOS Sierra (10.12) ships with an improved SmartCard integration, including support for SmartCard Extensions¹, an updated CCID driver and bug fixes on the PC/SC framework². This translates into a clean and simple configuration for using a Yubikey to login to the macOS.

The login screen as well as Keychain-related operations will show a PIN placeholder instead of Password if the Yubikey is plugged in and has been paired before.

References

1. https://developer.apple.com/library/content/releasenotes/MacOSX/WhatsNewInOSX/Articles/OSXv10.html

2. https://ludovicrousseau.blogspot.pt/2016/09/macos-sierra-and-smart-cards-status.html