Ask HN: How obscure is this security protocol?

I've seen many discussions about how security by obscurity isn't itself effective. Though it's led me to think about some obscure protocols that I can't see any way anyone could just figure out. For instance, keep port 22 for ssh, but only allow it to accept a correct password if you previously in sequential order attempted to access ports 764, 964, 1102, otherwise make even a correct password input reject access. I'm still in the process of learning everything about server hosting, but I don't see any obvious flaws in this kind of construction, though it relies on this not being a widespread idea.