tunny

The book is not about a Tunny Machine, but does paint an interesting world if the Difference Engine had gotten funding.

Their faith in the Lorenz cipher aka Fish cipher codenamed Tunny also arguably cost them the war.

Colossus was used to crack Tunny (Lorenz cypher machine) used by German High Command, while the Bombe machines were used to attack Enigma.

Maybe you're thinking of William Thomas Tutte breaking the Tunny (sawfish) code?

Tony Sale, who lead the team that rebuilt Colossus, gave a talk about how the Tunny machine worked as well as Colossus and the rebuilding process.

Is this a more advanced version of Tunny [0]?

Look at what Justine Tunny did with Redbean.

Also Bill Tutte made a much greater mathematical contribution to cryptography and broke the rather more complex Tunny code - between the guy with the bad moustache and his generals.

The best garum, the so-called haimation, is made in this way: the intestines of tunny along with the gills, juice and blood are taken and sufficient salt is sprinkled on.

The fact that Tunny had been cracked was a highly classified secret for decades after the war - I've always felt that the Enigma story was used as a cover to hide what Bletchley Park had really been up to, secrets within secrets.

Johny Carincross was a spy who passed over raw intercepts decrypted with Tunny to the Soviet Union; so they got the German order of battle and other information in advance of the battle of Kursk; that sounds like a major contribution to winning the war (the spy was confirming information that the British passed on via official channels, however they seem to have put more trust in the reports of their spy).

Colossus isn't very far from the Bombe today, you might likely visit both on the same trip, but Turing didn't build it, and although it's clearly in some sense a computer, it is critically lacking in some features you'd want from a general purpose computer since it had a single purpose, to break Tunny in the mid 1940s.

This was used to crack the Lorenz ("Tunny") cipher.

A more complex evolution of the rotor machine concept, code named "Tunny" by the British, was used for fixed radio links (it was too large and delicate to be practical for naval applications), and Bletchley Park mounted a huge effort to decode it was well, which lead to the development of an electromechanical computer called Colossus.

The Japanese begin using "Purple" about this time (prior systems "Red" and "Blue" were not mechanical), the Nazis had Engima even before the war and have also been using Lorenz / "Tunny" for a few months although only in prototype and their Allied counterparts are using a roughly similar technology to Enigma (Typex) and another weird (but pragmatic) rotor machine the ECM Mark II.

Yup, Enigma was a side-show, the main deal was Colossus and the work to crack Tunny.

However, Colossus wasn't for Engima (it was for Tunny) and Turing didn't work on it.

If you haven't already, you should check out the C projects from Justine Tunny.