Friedrich Kasiski
Major Friedrich Wilhelm Kasiski (
29 November 1805–
22 May 1881) was a
Prussian
infantry officer,
cryptographer and
archeologist. Kasiski was born in Schlochau,
West Prussia (now
Czluchow,
Poland).
Kasiski enlisted in
East Prussia's 33rd Infantry
Regiment on
20 March,
1823 at the age of 17. In May
1824, he was promoted to the
rank of
Master Sergeant, and eight months later was
commissioned as a
Second Lieutenant in February
1825. It took fourteen years to earn his next
promotion when, in May
1839, he advanced to the rank of
First Lieutenant. His next advancement was quicker, promoted to
Captain 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 battalion.
In
1863, Kasiski published a 95-page book on
cryptography,
Die Geheimschriften und die Dechiffrierkunst (
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 (although it is possible
Charles Babbage was already aware of a similar method but had kept it secret). The method relied on the analysis of gaps between repeated fragments in the
ciphertext; such analysis can give hints as to the length of the
key used. This technique is known as
Kasiski examination.
The significance of Kasiski's cryptanalytic work was not widely realised at the time, and he turned his mind to
archaeology instead. The later years of his life were spent at Neustettin (
Szczecinek); 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 wrought a revolution in cryptology" (
The Codebreakers).
*
David Kahn,
The Codebreakers - The Story of Secret Writing, revised ed, Scribner, 1996. pp207–209.
* M. W. Bowers (
pseudonym Zembie), "Major F. W. Kasiski — Cryptologist",
The Cryptogram, Vol. XXXI(3) (January-February 1964) pp 53,58-59.
*
List of cryptographers*
Topics in cryptography
