Been meaning to post this for a while. It’s a good intro on the British/American program to break and read high-level German codes. It comes from an audio podcast by the National Museum of the Air Force, at Wright Patterson AFB in Dayton, OH.
If you’ve never been there, I highly recommend a visit… or two… or three!
I’m pretty sure its the largest air museum in the world, and any airplane lover or history buff could spend days there.
Anyway, the paragraphs below are transcribed from a lecture by a museum staff member (I can’t tell who) on the breaking of the Enigma machine-generated code that Nazi Germany used in WWII.
This was a legendary breakthrough by British intelligence, and there’s a whole field of study on how it was done and the strategic impact it had. The recently-released hollywood movie, Imitation Game, tells that same story in a very engaging way (I recommend it highly).
So, here’s the entire audio podcast, about 45min long. Most of it deals with the machine itself (you can tell he has one next to him as he lectures), or the decoding process at Bletchley Park outside London. But towards the end he covers how decrypted information from Enigma — which was codenamed Ultra–helped the Allies win the air war in Europe.
Hit the “play” button to listen.
At the 37:50 mark, he starts talking about the effects on air operations. If that’s all you want to hear, move the slider ahead to that point. Or just read this:
In terms of Air Force history, the effect of breaking Enigma on the air war, was in a couple of different places. FIrst off all, the Mediterranean. German convoys crossed the Mediterranean to reinforce North Africa and to get people out of North Africa were practically stopped, because they could not, they couldn’t move. Because we knew what they were going to do. Now you think, wait, if we know everything they’re going to do, won’t they figure out that we’ve broken Enigma? Well yeah, If they know. If we counter them at every turn, they’re gonna know that we’ve broken their codes.
There’s a way to avoid that. Every piece of actionable Enigma-based intelligence, which was called Ultra, the intelligence that resulted from Enigma decrypts was called Ultra. Every piece of actionable intelligence that came from Enigma had to be accompanied by a masking or accompanying form of intelligence. For example, you learn from enigma that a convoy is crossing the Med at such-and-such a place and such-and-such a time. You don’t just go and bomb them, because they’ll figure out that you’ve broken Enigma. You send aircraft to that vicinity to “accidentally” spot the convoy. So that the people in the convoy will believe that they have unfortunately been found by aircraft, and then you bomb them.
And that is exactly what happened in many cases. You couldn’t use Ultra without masking intelligence so that you didn’t give away the Enigma secret. And that’s an interesting part of it. You know, how many cases you think there were, where, you know, “we can’t attack there because we don’t have a mask. They’ll know. They’ll know the larger secret, so we have to let ‘em go”. I don’t know how many times that happened, but surely it must have happened a few times, that there was no mask.
Other things that breaking Enigma did for the air war? It gave us valuable intelligence in terms of damage reports in the strategic bombing campaign to take out synthetic oil plants, in the last years of the war. We knew what our bombing had done, and how successful or unsuccessful it was, because those facilities sent damage reports to Berlin and other places, using Enigma. Broken codes gave us good information on what we had or hadn’t done.
It also validated air warfare tactics. It made fighter sweeps over the main part of Germany more and more effective, because the Luftwaffe would move its aircraft around and give itself damage reports and instructions and readings on how much fuel was or wasn’t available, and move this person here, move that person there. This was all done with Enigma, because they did not ever figure out that Enigma was broken. So, it validated air tactics, led to more effective air warfare for us, gave us damage reports that validated strategic bombing initiatives. And, as I said, in the Mediterranean we were able to practically stop their convoys.