Thanks to everyone who reached out to me about the cryptography challenge this week and to those who worked on it silently. I hope it was at least a mildly fun diversion.
The winner of my undying admiration is myshkin, who had already solved the puzzle by the time I woke up the next morning. It's not much of a prize, but it's his!
Before I reveal the actual phrases, I'll describe my encryption method. As I said in the comments earlier, it's not the most bullet-proof encryption, but it works well enough for these purposes. Just don't use this method to smuggle secrets out of Moscow, okay?
Here are the two encoded phrases again: