This is almost easier than the Penultimate because this code relies on traditional methods of encryption. For those who've had trouble on my other difficult caches, there are no easily missed subtleties and no misdirection here. Solve some puzzles by The Rat before attempting this difficult cache. No hints until an intrepid few first break the code.
For the curious, the binary reference stems from the fact that this is cache #100001; I just had to give you only 1's and 0's to start!