Yubikey Monitor is an utility that detects a currently connected Yubikey, monitors it's presence and locks the workstation when it is removed. It also prevents login on unless the right Yubikey is reinserted.
Currently, the utility uses the Yubikey's serial number to validate the Yubikey but I'm working on using the challenge-response mode to make it fully secure.
Requires the Yubico API.
Super simple, but does exactly what it should.
A simple concept, well executed and very effective. Works with any YubiKey, including my YubiKey VIP, because it uses the serial number. Remove the VIP key > computer locked and can't be unlocked, even with the right password. Minimal configuration; no options - just does what it says on the tin. Recommended. And thank you.