  We present a quantum multi-factor authentication mechanism based on the
hidden-matching quantum communication complexity problem. It offers step-up
graded authentication for users via a quantum token. In this paper, we outline
the protocol, demonstrate that it can be used in a largely classical setting,
explain how it can be implemented in SASL, and discuss arising security
features. We also offer a comparison between our mechanism and current
state-of-the-art multi-factor authentication mechanisms.
