Late in 2010, however, Google unveiled an open source project called Google Authenticator that allowed the common smartphone to serve as the 'thing you have' factor. Issue, to be sure, but the complexity of public-key infrastructure (PKI) Neither have taken off with the general public. Security dongles and biometric fingerprint scanners, for example. Passphrases both fall under the 'things you know' umbrella, and while thereĪre commercially viable options for the latter two categories. You know,' 'things you have,' and 'things you are.' Passwords and Scheme involves requiring items from two or more of the categories 'things The security-conscious will tell you that a multi-factor authentication This article was contributed by Nathan Willis