The two-time pad wanted a 5-gram, not a neural net

The original puzzle, preserved on the Internet Archive: Decrypting the Two-Time Pad — scroll down past the other puzzles to find it. ITA ran a whole collection of these hiring puzzles ; the archive page above holds the retired ones. There is an old ITA Software hiring puzzle from around 2004: you intercept two messages, both encrypted with a one-time pad over a 46-character alphabet (space, A–Z ,…