Well, I haven't yet patented an alternative, but I think it's pretty clear that, in this climate of routine breaches, the old system of secret data is no longer viable.

But, if you're interested in building an alternative, then off the top of my head, I'd suggest that we've got the blockchain. We've all got omnipresent palm-sized computing devices. We've got 2FA schemes, and more. The tools are there for you to create a much more robust system than one that says "here are a handful of secret numbers. Don't let anyone else see them or else your life may be ruined".