https://hackernoon.com/how-to-implement-google-authenticator-two-factor-auth-in-javascript-091wy3vh3 https://hackernoon.com/how-to-implement-google-authenticato

https://hackernoon.com/how-to-implement-google-authenticator-two-factor-auth-in-javascript-091wy3vh3 https://hackernoon.com/how-to-implement-google-authenticator... I haven't read through this in complete detail but it generally looks like the correct algorithm.