Disclaimer: this is for an online game where players join alliance and corporations. The link @zelf mentions here is an older version of the software we use to verify in-game user names with a password they set through an auth interface (my alliance uses auth.w4rp.space). I'll happily give a demo of the (newer) whole thing in action.
on a side-note:
I should research creating SSO with SSB. that would be super cool!