Re: Military grade, but which military?
Not to dismiss the work of Bletchley, but to imply that Enigma wasn't strong encryption in its time is a bit specious - it was far, far stronger than what the Allies had available.
It took a decade of continued investment by the Polish, then the British secret services, plus the invention of a new kind of signals intelligence, a new branch of mathematics and an entirely new technology for performing computations just to perform brute-force on Enigma. With better operating procedures, an Enigma system was still economically infeasible to crack until well after the war.
In the end, the biggest aid to the Allies in cracking Enigma was good old military discipline: there were enough stations that sent short, known-plaintext messages ("Station XYZ, 1200, nothing to report") that the cryptanalysts had a greatly-reduced search-space to work with.
Had the Germans been ordered to begin every message with two random words from the day's newspaper (i.e., salting the plaintext), things would have been much harder for the Allies.