At this year's RSA2012 conference, Sophos is giving away cool crypto-puzzle T-shirts. Meet us on Booth #1817 and claim yours!

You don't have to be at the show to take part in the puzzle. The text to use in solving the puzzle is shown below:

#include~<string.h>!int~putchar(int~c);char~*m="noncen.cmh/alu/puyxs.hrhb\xd\xa";void~main(int~argc,char~**argv){if(argc>1&&strlen(argv[1])==8){int~i=0;while(*m){putchar(*m+(*m<0x41?0:argv[1][(++i>8?i=1:i)-1]-0x61));m++;};};}

Solve this puzzle and you'll get a URL. Visit the URL and you'll face the second stage. Solve this and email the answer to Naked Security writer Paul Ducklin and get in the draw to win a NERF N-STRIKE Vulcan EBF-25.

Source: http://nakedsecurity...win-a-nerf-gun/

Cheers,

kao.

Disclaimer: I am in no way affiliated with Sophos.

EDIT: edited topic title to keep automatic checker happy.

Edited February 28, 201213 yr by kao

aha!

looked at this for 10 mintes this morning, couldnt solve it.

Now i see they updated the code!

lol... got the url working.. .. second test.. ermm

The first one is kinda cheap, you can solve it without a computer.

Number two is... irritating, not sure what they're getting at.

Edited February 28, 201213 yr by Killboy

The first one is kinda cheap, you can solve it without a computer.

Number two is... irritating, not sure what they're getting at.

Yea...first check is easy...... second task.. well.. i understand what they're getting at.. but don't have the slightest idea on how to start on it....

Wow I just spent half an hour writing a multithreaded python solution just to find out CPython only allows running one thread at a time. WTF. Now I'm running 7 python instances in their own cmd window. All for one stupid toy gun

I just spent half an hour writing a multithreaded python solution just to find out CPython only allows running one thread at a time. WTF.

The challenge is supposed to be fun, not frustrating. On the other hand, I failed to solve even the first stage. Crypto-puzzles are not my field of expertise..

The challenge is fun, great afternoon entertainment. Python, on the other hand, isn't

Got it

Make sure you use all the tips on the website of the second stage, you'll need a hint if you didn't accidentally use the right 'source'.

Edited February 28, 201213 yr by Killboy

Got the first one down. Had to use a compiler. I'm not a crypto/math kinda guy so compiling it worked a little easier for me. The second one confused me. I didn't understand how you could calculate what they want. Before giving up I checked the twitter link and the right "source" was found. I still didn't go through with all the stuff afterwords but I think I get the process now.

I used a python script with shutil.copyfileobj to append the files in stream and passed a temp file to md5 hashlib. This worked out fine but I think there must be a faster way. Glad the final answer wasn't too far up from the prodcut of xy... The Dragon Tattoo challenge Sophos did the week of the movie release was pretty good.

They posted a video solution on Sophos for the RSA 2012

..http://nakedsecurity.sophos.com/2012/03/20/video-how-to-solve-the-rsa-2012-sophospuzzle/