Both security keys and fingerprint readers are devices that require physical contact in order to give you access to an account, but the similarities end there. A fingerprint reader stores a copy of your fingerprint on your local machine, and then verifies that your finger is a match every time you log in. Fingerprint readers are used almost exclusively to give users physical access to their computers, while security keys are used with web services and online accounts. A security key relies on the user to tap it, and while it will accept a tap from anyone, it verifies access in the cloud.