G Mark Hardy

February 10, 2012 at 12:24 pm

Very impressive! This is the most complex badge puzzle I’ve seen for a hacker conference. Although it took nearly four years for a solution to be published, Darth is the guy I would have bet on to do it.

(Darth — Now you can turn your attention to my business card puzzle — it’s been unsolved for the same length of time :)

Darth Null

February 10, 2012 at 10:56 pm

Yeah, every couple months I look at that again, and after a couple days, put it away. I’m pretty sure I know what needs to happen, but just can’t find an easy way to do it short of brute forcing it. I sometimes think I should just write a brute force tester and let it run — if I’d started that a couple years ago it’d be solved by now.

I was really excited when you updated the cards last year, hoping that now I could try an attack in depth, but it appears you did the right thing and did not reuse key/plaintext in any way that’d help me. :(

G Mark Hardy

February 20, 2012 at 11:29 am

Aww, no crypto shortcuts? Never say never. Anyway, there are a couple thousand of my business cards now in circulation, and I tell anyone who is interested the same thing — “everything you need to solve this is on the card,” and “it can be solved with pencil and paper.” Except I used pen when building it — I can never seem to find a pencil when I need one. :)