I think they did want it broken, they seemed to treat everything like a game. My guess is that they didn't count on the errors and that made things much harder

I think they did want it broken, they seemed to treat everything like a game. My guess is that they didn't count on the errors and that made things much harder. The time to send random message is after the successful decryption of the first few. Drop a few hints in the early messages so that they're valuable to the police, then hit them with the time waster once they're hooked. Tell the public it has the answers and claim the cops aren't even trying, etc.