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NEMA (machine)

NEMA (machine) is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand NEMA (machine) rather than just read about it. In short: In the history of cryptography, the NEMA (NEue MAschine) ("new machine"), also designated the T-D (Tasten-Druecker-Maschine) ("key-stroke machine"), was a 10-wheel rotor machine designed by the Swiss Army during World War II as a replacement for their Enigma machines. History The Swiss became aware that their current machine, a commercial Enigma (the Swiss K), had been broken by both Allied and German cryptanalysts.

NEMA (machine) — main illustration
NEMA (machine) — illustration

Key takeaways

  • NEMA (machine) belongs to computer science; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect NEMA (machine) to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of NEMA (machine) from memory before moving on to harder problems.

Reference excerpt

In the history of cryptography, the NEMA (NEue MAschine) ("new machine"), also designated the T-D (Tasten-Druecker-Maschine) ("key-stroke machine"), was a 10-wheel rotor machine designed by the Swiss Army during World War II as a replacement for their Enigma machines.

History The Swiss became aware that their current machine, a commercial Enigma (the Swiss K), had been broken by both Allied and German cryptanalysts. A new design was begun between 1941 and 1943 by Captain Arthur Alder, a professor of mathematics at the University of Bern. The team which designed the machine also included Professors Hugo Hadwiger and Heinrich Emil Weber. In the spring of 1944, the first prototype had become available. After some modifications, the design was accepted in March 1945, and production of 640 machines began the following month by Zellweger AG. The first machine entered service in 1947. NEMA was declassified on 9 July 1992, and machines were offered for sale to the public on 4 May 1994.

The machine NEMA uses 10 wheels, of which four are normal electrical rotors with 26 contacts at each end that are scramble wired in a way unique to each rotor type; one is an electrical reflector (like the Enigma's Umkehrwalze) with one set of 26 pairwise cross connected contacts; and the remaining five are "drive wheels", with mechanical cams that control the stepping of the rotors and the reflector. The wheels are assembled on an axle in pairs consisting of a drive wheel and an electrical rotor.

The NEMA machine weighs about 10 kg and measures approximately 36×32×14 cm.

See also Fialka Typex SIGABA

References

Further reading Geoff Sullivan and Frode Weierud: The Swiss NEMA Cipher Machine. Cryptologia, 23(4), October 1999, pp310–328. Walter Schmid: Die Chiffriermaschine Nema. 109 pages, third edition, February 2005, Hombrechtikon ZH, Switzerland

External links

Frode Weierud's page on the NEMA – photographs and a simulator David Hamer's page on NEMA – includes records of NEMA selling prices: [1] Bob Lord's page on the NEMA – includes scanned manuals Jerry Proc's NEMA page

Illustrations

NEMA (machine) illustration
NEMA (machine) illustration
NEMA (machine) illustration
NEMA (machine) illustration
NEMA (machine) illustration

Worked examples

Example 1 — a first encounter with NEMA (machine)

Start with the simplest possible case. Write down what NEMA (machine) claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to NEMA (machine) before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about NEMA (machine) ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of NEMA (machine)

In research
NEMA (machine) appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses NEMA (machine) in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
NEMA (machine) is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cryptographic hardware, Military equipment of Switzerland, Rotor machines, so understanding it makes those chapters shorter.
In everyday life
Look for NEMA (machine) outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study NEMA (machine) in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what NEMA (machine) means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain NEMA (machine) out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NEMA (machine) in simple terms?

In the history of cryptography, the NEMA (NEue MAschine) ("new machine"), also designated the T-D (Tasten-Druecker-Maschine) ("key-stroke machine"), was a 10-wheel rotor machine designed by the Swiss Army during World War II as a replacement for their Enigma machines. History The Swiss became aware…

Why does NEMA (machine) matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study NEMA (machine)?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on NEMA (machine).

Tags

  • Cryptographic hardware
  • Military equipment of Switzerland
  • Rotor machines

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