CTF Puzzle!

Recently I've been playing Capture The Flag (CTF) style puzzles. These involve using technical knowledge to derive a hidden message. This can include breaking encryptions, exploiting program / file type flaws, reverse engineering and general intuitive problem solving. Google has a great website that offers these puzzles as educational exercises at beginner and competition levels.

Here's my go at crafting one of these puzzles: CTF, think you can decrypt the message? - The puzzle has perfect information, good luck!