This is an unsanitised account of how I solved the GCHQ challenge at http://www.canyoucrackit.co.uk/. According to the BBC the competition began in secret on the 3rd of November 2011 and will continue until the 12th of December. I was going to hold back this publication until the contest ended but a solution has just made it to the front page of slashdot so I think the jig is up! This writeup includes the wrong turnings I took and the bad assumptions I made along the way so any reader can see...
