Major Friedrich Wilhelm Kasiski (29 November 1805 – 22 May 1881) was a German

infantry Infantry, or infantryman are a type of soldier who specialize in ground combat, typically fighting dismounted. Historically the term was used to describe foot soldiers, i.e. those who march and fight on foot. In modern usage, the term broadl ...

officer An officer is a person who has a position of authority in a hierarchical organization. The term derives from Old French ''oficier'' "officer, official" (early 14c., Modern French ''officier''), from Medieval Latin ''officiarius'' "an officer," fro ...

cryptographer Cryptography, or cryptology (from "hidden, secret"; and ''graphein'', "to write", or '' -logia'', "study", respectively), is the practice and study of techniques for secure communication in the presence of adversarial behavior. More gen ...

and

archeologist Archaeology or archeology is the study of human activity through the recovery and analysis of material culture. The archaeological record consists of artifacts, architecture, biofacts or ecofacts, sites, and cultural landscapes. Archaeol ...

. Kasiski was born in Schlochau,

Kingdom of Prussia The Kingdom of Prussia (, ) was a German state that existed from 1701 to 1918.Marriott, J. A. R., and Charles Grant Robertson. ''The Evolution of Prussia, the Making of an Empire''. Rev. ed. Oxford: Clarendon Press, 1946. It played a signif ...

(now

Człuchów Człuchów (, ''Człochòwo'', or ''Człëchòwò''; ) is a town in the region of Gdańsk Pomerania, northern Poland, with 13,350 inhabitants as of December 2021. It is the capital of Człuchów County in the Pomeranian Voivodeship. Location ...

, Poland).

Military service

Kasiski enlisted in

East Prussia East Prussia was a Provinces of Prussia, province of the Kingdom of Prussia from 1772 to 1829 and again from 1878 (with the Kingdom itself being part of the German Empire from 1871); following World War I it formed part of the Weimar Republic's ...

's 33rd Infantry

Regiment A regiment is a military unit. Its role and size varies markedly, depending on the country, military service, service, or administrative corps, specialisation. In Middle Ages, Medieval Europe, the term "regiment" denoted any large body of l ...

on 20 March 1823 at the age of 17. In May 1824, he was promoted to the

rank A rank is a position in a hierarchy. It can be formally recognized—for example, cardinal, chief executive officer, general, professor—or unofficial. People Formal ranks * Academic rank * Corporate title * Diplomatic rank * Hierarchy ...

master sergeant A master sergeant is the military rank for a senior non-commissioned officer in the armed forces of some countries. Israel Defense Forces The (abbreviated "", master sergeant) is a non-commissioned officer () rank in the Israel Defense Force ...

, and eight months later was

commission In-Commission or commissioning may refer to: Business and contracting * Commission (remuneration), a form of payment to an agent for services rendered ** Commission (art), the purchase or the creation of a piece of art most often on behalf of anot ...

ed as a second lieutenant in February 1825. It took fourteen years to earn his next

promotion Promotion may refer to: Marketing * Promotion (marketing), one of the four marketing mix elements, comprising any type of marketing communication used to inform or persuade target audiences of the relative merits of a product, service, brand or i ...

when, in May 1839, he advanced to the rank of

first lieutenant First lieutenant is a commissioned officer military rank in many armed forces; in some forces, it is an appointment. The rank of lieutenant has different meanings in different military formations, but in most forces it is sub-divided into a se ...

. His next advancement was quicker, promoted to

captain Captain is a title, an appellative for the commanding officer of a military unit; the supreme leader or highest rank officer of a navy ship, merchant ship, aeroplane, spacecraft, or other vessel; or the commander of a port, fire or police depa ...

in November 1842. Kasiski finally retired from active service with the rank of major on 17 February 1852. Between 1860 and 1868 he was the commander of a

National Guard National guard is the name used by a wide variety of current and historical uniformed organizations in different countries. The original National Guard was formed during the French Revolution around a cadre of defectors from the French Guards. ...

battalion A battalion is a military unit, typically consisting of up to one thousand soldiers. A battalion is commanded by a lieutenant colonel and subdivided into several Company (military unit), companies, each typically commanded by a Major (rank), ...

Cryptography

In 1863, Kasiski published a 95-page book on

cryptography Cryptography, or cryptology (from "hidden, secret"; and ''graphein'', "to write", or ''-logy, -logia'', "study", respectively), is the practice and study of techniques for secure communication in the presence of Adversary (cryptography), ...

, ''Die Geheimschriften und die Dechiffrir-Kunst'' (German, "Secret writing and the Art of Deciphering"). This was the first published account of a procedure for attacking polyalphabetic substitution ciphers, especially the

Vigenère cipher The Vigenère cipher () is a method of encryption, encrypting alphabetic text where each letter of the plaintext is encoded with a different Caesar cipher, whose increment is determined by the corresponding letter of another text, the key (crypt ...

( it is possible

Charles Babbage Charles Babbage (; 26 December 1791 – 18 October 1871) was an English polymath. A mathematician, philosopher, inventor and mechanical engineer, Babbage originated the concept of a digital programmable computer. Babbage is considered ...

was already aware of a similar method but had not published it). The method relied on the analysis of gaps between repeated fragments in the

ciphertext In cryptography, ciphertext or cyphertext is the result of encryption performed on plaintext using an algorithm, called a cipher. Ciphertext is also known as encrypted or encoded information because it contains a form of the original plaintext ...

; such analysis can give hints as to the length of the key used. This technique is known as

Kasiski examination In cryptanalysis, Kasiski examination (also known as Kasiski's test or Kasiski's method) is a method of attacking polyalphabetic substitution ciphers, such as the Vigenère cipher. It was first published by Friedrich Kasiski in 1863, but seems to ...

. The significance of Kasiski's cryptanalytic work was not widely realised at the time, and he turned his mind to

archaeology Archaeology or archeology is the study of human activity through the recovery and analysis of material culture. The archaeological record consists of Artifact (archaeology), artifacts, architecture, biofact (archaeology), biofacts or ecofacts, ...

instead. The later years of his life were spent at Neustettin (

Szczecinek Szczecinek (; ) is a historic city in Middle Pomerania, northwestern Poland, capital of Szczecinek County in the West Pomeranian Voivodeship, with a population of more than 40,000 (2011). The town's total area is . The turbulent history of Szcze ...

); the 11th edition of Encyclopædia Britannica cited a scholarly article by Kasiski in its entry on the town. Historian David Kahn notes, "Kasiski died on May 22, 1881, almost certainly without realizing that he had written a revolution in cryptology" (''

The Codebreakers ''The Codebreakers – The Story of Secret Writing'' () is a book by David Kahn (writer), David Kahn, published in 1967, comprehensively chronicling the history of cryptography from ancient Egypt to the time of its writing. The United States gover ...

'').

Publication

* F. W. Kasiski
''Die Geheimschriften und die Dechiffrir-Kunst''
(Berlin, (Germany): E. S. Mittler und Sohn, 1863).

External links

* - A video that shows how to break a Vigenère ciphertext using Kasiski's test

References

* David Kahn, ''

– The Story of Secret Writing'', revised ed, Scribner, 1996. pp. 207–209. * M. W. Bowers (pseudonym ''Zembie''), "Major F. W. Kasiski – Cryptologist", ''The Cryptogram'', Vol. XXXI(3) (January–February 1964) pp. 53,58–59.

Military service

Cryptography

Publication

External links

References

See also