
German Cryptanalytic Attacks on the British World War II “TYPEX” Machine - sohkamyung
https://www.cs.columbia.edu/~smb/blog//2018-08/2018-08-24.html
======
Moodles
This is nice to see because I've always found it surprisingly difficult to get
any information whatsoever on the German efforts in WWII.

Generally rotar machines were used a lot before WWII by banks and such. The
Enigma and Typex were much more difficult to crack than commercial products
because of the plugboard, while commercial machines only had spinning rotors.
I think the Typex didn't have the weakness that letter x encrypts to x either.
The Germans basically concluded that it was even tougher than the unbreakable
Enigma so gave up.

Germany also had little success because, unlike in Bletchley Park, they didn't
exactly tolerate eccentric academic types. The codebreaking efforts of the
Germans were also so incredibly fragmented across different departments that
once two different departments had a bust up on the street.

Wikipedia has some good references:
[https://en.wikipedia.org/wiki/German_code_breaking_in_World_...](https://en.wikipedia.org/wiki/German_code_breaking_in_World_War_II#cite_note-2)

~~~
raffael-vogler
> The codebreaking efforts of the Germans were also so incredibly fragmented
> across different departments that once two different departments had a bust
> up on the street.

Hitler also systematically embedded a divide and conquer principle in
organizations. Basically all institutions were duplicated to have them compete
against each other instead of potentially forming an opposition against
Hitler.

~~~
imrelaxed
USSR did the same thing. Pretty sure it was done to promote competition and
not for divide and conquer. Secret police was more than enough to handle
dissidents. Hitler and his party actually had a lot of support because most of
the bad stuff they did was hidden from the people or justified super hard
through propaganda. And as bad as the Nazis were overall they still managed to
have major successes in economy and science.

~~~
SerLava
>And as bad as the Nazis were overall they still managed to have major
successes in economy and science.

They weren't actually succeeding economically. They simply racked up internal
debt, stopped paying their foreign debt, and invaded Europe in order to
plunder it's riches and resources.

They had been plummetting toward economic collapse.

They knew they weren't ready to defeat the UK militarily, knew their
technology wasn't properly built up yet, and actually didn't anticipate their
own early military successes in mainland Europe.

But they had no choice. Fascism itself had backed Hitler into a corner. It was
invasion or abdication (which was unimaginable).

------
sgt101
Interesting conjecture at the end; GCHQ retained two Colossus machines until
the 1970's. The Russians knew that Colossus existed and GCHQ knew that the
Russians knew. Why retain Colossus - people tend to say that it was because
there were networks of rotor machines in use in less sophisticated countries,
but given the us or them nature of the cold war it seems unlikely that there
was sufficient value in retaining them through the 50's. My guess is that
there was some sort of elaborate counter bluff played out with the Soviets;
that they believed that the Brits thought that they were unaware of Colossus
and so would be duped by traffic sent over rotor networks... but what was in
it for the Brits?

~~~
qubex
Colossus was used to break Tunny (encrypted teleprinter traffic) and, as far
as I can deduce (despite that machine also using rotors of an entirely
different kind) was useless in analysing Enigma-type traffic. The desire to
hide the achievements of Colossus at Bletchley Park was an (apparently
successful) attempt to goad the Soviet Union into adopting similar cipher
systems after the war so that the same techniques could be applied by the
Western powers to read Soviet signals. The ruse largely worked.

~~~
tialaramex
Yes! This is so important and yet so often not understood even by people
who've supposedly been to Bletchley where they spell it out pretty clearly in
their museum.

Tunny (the German thought of this as "Lorenz" because that was the
manufacturer name) is an actual stream cipher, more or less. It's making
pseudo-random bits and XORing them with plaintext to produce a ciperhtext. The
plaintext is Baudot code rather than, say, ASCII, but it's definitely bits.
Lorenz is doing this in (by modern standards) a ludicrously mechanical
steampunk-looking way, but that's what it's doing. Even though to our modern
eyes it looks not so different from Enigma in terms of the principle of
operation it's entirely different and radically more like how things would be
done decades later.

Salsa20 and ChaCha are modern stream ciphers, they're designed for modern
binary computers rather than a mechanical contraption, but the core underlying
principles are the same as Lorenz. If you can make a lot of "random-looking"
bits from a small key you can XOR them with your plain input to produce a
ciphertext, nobody can decipher it without knowing the key in order to
generate the same "random" bits.

Most cryptosystems you use today have block ciphers inside them, which work
quite differently, but some will have a stream cipher, a descendent of Lorenz
inside them - spiting out "random-looking" bits.

~~~
Moodles
Yeah, the efforts of Bill Tutte and Tommy Flowers to break the Lorenz were
amazing. People only remember Turing, but there are plenty of forgotten heroes
in Bletchley who never got the recognition they deserve.

~~~
theluketaylor
Bill Tutte is a local hero here in Waterloo. He was already an extremly
respected professor of the math faculty, but since the moratorium on secrets
at Bletchley has been lifted he has been inducted into the Order of Canada and
had a street named after him, among other honours.

It is sad the revelation of his involvement came so close to the end of his
life. He certainly deserved much more recognition.

