Rare Interviews with Enigma Cryptanalyst Marian Rejewski – Source: www.schneier.com

Clive Robinson •

May 3, 2024 8:00 AM

@ ALL,

Like many cryptographers that come eventually to public attention Marian Rejewski had an interesting life.

Sadly for “security reasons” his skills went to waste during WWII when he arrived in Britain.

As British cryptographer Alan Stripp said in his 2004 book on the three Polish Cryptographers,

“Setting them to work on the Doppelkassetten system was like using racehorses to pull wagons.”

(The Doppelkassetten system was a low grade hand cipher used by the SS and SD and similar to “double Playfair”).

noname •

May 3, 2024 9:47 AM

Wonderfully, the first 61 pages of his Marian Rejewski’s biography, The First Enigma Codebreaker, are available online.

“He began studying insurance mathematics at the University of Göttingen, about which he said: ‘[the Institute of Mathematics was high up. It was like going to Mecca.” His adventure with cryptology had only just begun.”

Clive Robinson •

May 3, 2024 12:21 PM

@ JGar,

Re : Method of battons.

The history of breaking rotor machines is somewhat interesting.

Few realise that you can make an analogue of the rotor systems used in the Enigma like systems with a ruler with elasticated loops and strips of paper or wooden rods / battens with the wheel input to output mappings on them.

This analogue was used in a system the French invented and because of the analogue became known as –if memory serves correctly– “déchiffrer du bâton”

Or in English “The method of rods / battens”.

This simple analogue can be used in the hand breaking of many ciphers that are in some part automated by simple mechanics.

In fact it can be used as the basis for simple “adding” –thus subtraction– and multiplication.

You used to be able to purchase such “calculators” back in the 1960’s and early 1970’s when I purchased one to get more accurate results than a slide rule.

http://www.vintagebritishcalculators.info/html/exactus.html

If you look carefully you can see how you “slid the rods” with the stylus.

This model became redundant in 1971 when on Valentine’s day plus one,

https://en.m.wikipedia.org/wiki/Decimal_Day

The “British Isles” stopped using LSD… that is the Latin currency denominations “Librae, Solidi, and Denarii”(LSD)[1].

All that was “required” to make the changes were a new “face plate” and using the same rods / slides across the device.

It’s something we forget in our “IT World” that if you design your system well and established on the basic principles and methods, then required changes in the face of changing reality can be very simple and minimal.

[1] Yup that currency that you hear English old’uns waxing lyrical about, was not “British” but a hang over from the days of the Western Roman Empire. Under Frankish emperor Charlemagne LSD cut through the mess of different systems that had been inhibiting trade and commerce, by creating a new uniform system.

Which back in the 8th century was spread and thus became standardized by trade across Western Europe and much later many places around the globe via the “British Empire”.