Some folks have been asking for hints on the first reverse-engineering challenge so here's a short blog post that will hopefully help :)
First of all, however, this challenge is intended to stretch you, test you and make you work as a team whilst learning new skills.
The first challenge is a classical puzzle with three riddles that the contestant needs to get right, however, the riddles are not the actual reversing challenge.
The puzzle will not work unless three conditions are met and this is the key to getting it right.
Each contestant needs to reverse the binary to find what those conditions are.
As a clue for the first conditions are simple: the filename of the program needs to match an API needed for the program to decrypt properly.
You need to reverse the function to find out about the API.
Olly-based debugger (OllyDbg itself, Inmunity etc.) or IDA (in its free or paid versions)
P.S. To reassure you, this is one of the harder, if not the hardest, challenge due to the length of time that you have to solve it (almost two months) and the fact that most people aren't reversing specialist!!
You will definitely be able to solve quite a few of the challenges on the day. We will also be on hand during the day to provide some pointers (not too many now, but general nudges).
Additionally, the second pre-challenge is a lot easier and will involve skills that are more familiar to you.