TokenLock - Lock your Mac when you walk away.
TokenLock is a screen locking application for Mac. It will lock your mac screen if you either:
Remove a USB device you have designated from your Mac.
Move a bluetooth device out of bluetooth range of your Mac.
Tokenlock was designed to increase the security of your Mac by automatically turning on the screen saver, or locking your system whenever a USB device or a Bluetooth device are removed from your system.
You can tell it to monitor almost any USB device, such as a hard token like YubiKey, a removable flash drive or any other USB device for that matter. Whenever the device is disconnected it will immediately lock your Mac.
Tokenlock can monitor any Bluetooth device to check if it is removed from range, such as your cellphone, headset or other Bluetooth device. Token lock checks periodically based on a schedule you choose to see if the Bluetooth device can still be seen.