[withinboredom]

The problem is that you let the enemy know the detail of your intel. Using compartmentalization, they can locate leaks and determine how you are getting the intel.

As a military, you never want to give that away. Looking at WWII, the UK/US were able to decrypt messages daily from the Germans (thanks to Turing!), but they pretended they couldn't so the Germans wouldn't change their encryption scheme.

[H8crilA]

But they already share it, just in a messy format. No need to philosophise.

[withinboredom]

I'm not philosophising, this was literally my job in the military and worked with a number of analysts who worked on this sort of thing.

[H8crilA]

I see, but this military does share this very information.

[withinboredom]

They share enough information to be useful to the civilians but not enough information to show capabilities. If everything is automated, the enemy can subscribe to the automation and work out radar capabilities, response times, and accuracy. Those are all terrible things for an enemy to use and abuse.

[sidewndr46]

This is a significant mistelling of the history of the German "Enigma" device. Significant usage of Enigma was done during the war in a manner that was secure enough to prohibit interception.

Turing's methods are brilliant as are the contributions of numerous other cryptographers. They relied on numerous operational failures of some branches of the military to be possible. So it was not from "the Germans", but from specific branches of the military that failed to follow already established best practices

[withinboredom]

I'm not sure what you mean. They used daily weather reports to decrypt the enigma for that day, so I'm not sure how that is an operational failure. If you know part of the cleartext, it's possible to brute-force any encryption given enough time.

https://www.accuweather.com/en/weather-news/how-british-cryp... gives a pretty decent summary.

[Two4]

Sure, but those known text attacks were made significantly easier by German operators using (and reusing) non-random and easily guessable encryption parameters. Once the keyspace became small enough to search, they were able to brute force the encryption.

[sidewndr46]

You're mentioning one technique as if it was the comprehensive method of compromising the Enigma. It was not. The example you give would only work for the Kriegsmarine transmissions for example. The Luftwaffe had its own system with its own operational failings.