Creation by an unrecognized genius.

Seriously, don't you understand? We're talking about cracking password-protected save files.
Wouldn't it also be interesting to try and find a vulnerability in the HD+ protection?

Besides cracking save files, there's another way to unlock a map: by simulating its generation based on the seed specified in the description. Technically, this is quite feasible, and I did it when I was looking for a bug in the program for calculating guards, and I think it's easier than cracking password-protected save files. But still, it's quite a hassle and requires special skills and knowledge. If a person can (and wants to) do this for cheating purposes, I think they are capable of finding a way to bypass any reasonable protection.