Comment Re:vBulletin (Score 2) 259
Writing a program that solves a Calcudoku is pretty simple, actually. Hell, a 6x6 only has a couple hundred possibilities; that's a piece of cake to brute-force. I think right now you're more relying on security through obscurity -- it's not been broken because it's not yet used often enough to be a tempting target for a spambot creator.