This is the same design as RSA SecurID: http://en.wikipedia.org/wiki/SecurID http://en.wikipedia.org/wiki/SecurID I had no idea you could also do Google's two

This is the same design as RSA SecurID: http://en.wikipedia.org/wiki/SecurID http://en.wikipedia.org/wiki/SecurID I had no idea you could also do Google's two factor auth with SMS messages. That seems really flaky.