system
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human
What happend to the Enigma Machine?

In school we are currently doing a short unit on Turing and how he decrypted the Enigma machine.

I was wondering if there was anything which improved upon the designs of the Enigma machine?

Or something that became the "spiritual" child of the enigma machine during the korean/Vietnam time period in order for the super powers to protect their secret messages/orders?

I've tried to do some searching myselfand have found nothing. My history teacher is drawing a blank as well.

So I was wondering if any of you knew anything?
gpt
It's interesting to note that the Enigma was technically obsolete by the start of WWII and should not have been used by the German military.  A big problem with the Engima and other devices like it is that it does a piss poor job of increasing entropy (i.e. randomness) of the cipher text.  What this means is that the message you send over the air (and which the enemy can intercept) is packed full of meaning and can be attacked relatively easily.  This is laborious by hand, which is what the Enigma relied upon.  However, once computers arrived on the scene at Bletchley park, Enigma was done.

The current gold standard for encryption was invented just after WWI.  The Vernam cipher, or "one time pad" is a deceptively simple way of encrypting messages.  You take your message and convert it to binary, then you take a random sequence of 1's and 0's (i.e. the "key") and XOR the message with it.  This can be done by hand and the outcome is indistinguishable from random noise *unless* you have the key.  This method of encryption is impossible to attack, and provably so.  If the key is random, so will the cipher text be.  The big problem with using a vernam cipher is that keys can only be used once, so it is necessary to get those random keys to the person who will need them to decode the message.  The Germans could have sent key-books out with U-boats, etc. and used Vernam ciphers instead of the Enigma.  If they had done this, their messages would have been impossible to decrypt unless the allies managed to capture one of the key-books.  Fortunately for the allies, the Germans did not do this.

It's important to note that the Germans really *could* have used the Vernam cipher instead of Enigma, because they were *already* using it for high level diplomatic communications from the interwar Weimar republic era onwards.  The allies also made extensive use of the vernam cipher in a variety of forms during WWII, and ever since.  It's bizarre that the grossly inferior Enigma system is so much more famous, but understandable.  Enigma machines are intrinsically linked with the development of the computer, and it's difficult to say how and when computer would have evolved were it not for Enigma.  

Today, using a Vernam cipher remains difficult in a lot of circumstances.  If you aren't in regular physical contact with the person you are sending coded messages to, you have to rely on an intermediary to transfer key material.  How much trust can you place in your intermediary?  Also, how can you communicate with someone you've never met, but be assured it's not somebody pretending to be them?  The vernam cipher does nothing for authentication.  Public key encryption solves many of these problems, although at the cost of being technically possible (but currently very difficult) to crack.

If you're curious about the state of the art, that would probably be quantum key distribution in combination with the venerable vernam cipher.  Google BB84 for the earliest, simplest form if you're curious.  QKD allows two widely separated people to obtain a random key that they both know, but which is impossible for other people to intercept (in theory).  Once they have that key, the rest is relatively easy.