YRBFYR OTHN: Nicholas Rescher Resurrects History’s First Sophisticated Wartime Coding Machine

A spaghetti maker, an old-fashioned typewriter, a device used to create Braille. These are just a few of the guesses people have made upon encountering the mysterious-looking machine that will soon be on display at the University of Pittsburgh. 

The machine is actually a cipher device—originally designed in the 1670s—for coding and decoding encrypted messages. Celebrated German mathematician G.W. Leibniz designed the first-of-its-kind machine for the benefit of Holy Roman Emperor Leopold I, who was frequently at war with France and the Ottoman Empire. But the mathematician’s invention was never built—until now, more than 325 years later.

Pitt Distinguished University Professor of Philosophy Nicholas Rescher—one of the world’s leading authorities on Leibniz—has constructed the cipher machine using
memos and other documents from Leibniz, who shares credit with Isaac Newton for inventing modern calculus and other fields of mathematics. 

Rescher’s working device will be on display in Pitt’s Hillman Library beginning Dec. 14 at a special 2 p.m. reception that will take place in the Thornburgh Room on the library’s first floor, featuring special guest Busso von Alvensleben, Germany’s Consul General in New York. The event is free and open to the public.

“Although there have been earlier cipher devices such as slides or wheels, Leibniz’s remarkable apparatus was the first actual cipher machine,” said Nicholas Rescher. “His mystery code-maker was thought of nearly 250 years before its most famous descendant, the ENIGMA cipher machine used by the German military during World War II.”

In the late 1600s, messages were encoded by replacing each letter with an equivalent character according to a simple alphabet table. However, Leibniz—a multitalented inventor—saw that the resulting code was too easy to break. 

Earlier in his career, Leibniz had constructed a calculating machine that performed operations beyond simple addition and subtraction using a Staffelwalze, or step drum. In his design of the cipher machine, Leibniz incorporated that same step drum from his calculating machine so that the cipher could encode using a harpsichord-type keyboard. The embedded step drum would advance irregularly, producing variability in the text and making the cipher harder to crack. This step drum was the keystone to Rescher’s realization of Leibniz’s design.

The newly constructed machine—valued at the price of a “nice new car”—took two years to build with the help of Richard Kotler, a retired Pittsburgh engineer who helped fill in some of the gear-related details, and Klaus Badur, a Leibniz machine expert living in Garbsen, Germany. Following Leibniz’s blueprint, the team worked on the construction of the 17th-century design in collaboration with Wolfgang Rottstedt, a German machine operator specializing in historical recreations. 
Leibniz detailed this complex cipher machine in a memorandum to Leopold I. His discussion with the emperor made it clear that he intended the machine be used by a “potentate or high person,” which better explains why his documents were kept secret. “As a result of this secrecy,” said Rescher, “all we know about the machine came from Leibniz’s pitch to the emperor.”

But the emperor was not interested in Leibniz’s cipher machine. Rescher says it’s because the monarch and his retinue “mistakenly had an all-too-common confidence in the security of their existing procedures.” As a result, Leibniz never published his memorandum, and the cipher device was never built. 
After becoming aware of Leibniz’s wife’s intentions to “run off” in the early 1700s, King George I left her under house arrest and ordered that Leibniz’s papers—more than 200,000 documents—be impounded. Fortunately, those papers survived after Leibniz’s death in 1716 and have been gradually published by German scholars over the past several decades. 

Rescher chronicles Leibniz’s story and his own account of reconstructing the Leibniz cipher machine in a booklet, “Leibniz and Cryptography,” which will be available at the Dec. 14 reception. 

Rescher is the cochairman of Pitt’s Center for Philosophy of Science. In a productive research career extending over six decades, Rescher has established himself as a systematic philosopher of the old style and author of a system of pragmatic idealism which weaves together threads of thought from Continental idealism and American pragmatism. He has authored, coauthored, or edited more than 100 books to this credit, ranging over all areas of philosophy with 16 of them translated from English into eight other languages. The Encyclopedia of Bioethics credits Rescher with writing one of the very first articles in the field. Twelve books about Rescher’s philosophy have been published in four languages. 

Rescher has served as president of the American Philosophical Association, American Catholic Philosophy Association, American G. W. Leibniz Society, C. S. Peirce Society, and American Metaphysical Society as well as secretary general of the International Union of History and Philosophy of Sciences. He is the recipient of eight honorary degrees from universities on three continents and was awarded the Alexander von Humboldt prize for Humanistic Scholarship in 1984, the Belgian Prix Mercier in 2005, and the Aquinas Medal of the American Catholic Philosophical Association in 2007. In 2011 he was awarded the premier cross of the Order of Merit (Bundesdienstkreuz Erster Klasse) of the Federal Republic of Germany in recognition of contributions to philosophy and to German-American cooperation in this domain. 

From his personal library, Rescher has donated various Leibniz-related artifacts to Pitt’s University Library System—most notably a rare 1711 letter penned by Leibniz himself.

[The code used in this story’s headline reads, “DECIPHER THIS: Pitt Professor Resurrects History’s First Sophisticated Wartime Coding Machine,” and was encoded by the reconstructed cipher machine.]