Ernst Fetterlein
Encyclopedia
Ernst Constantin Fetterlein (3 April 1873–1944) was a Russian cryptographer who later defected to Britain
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

.

Fetterlein was born in St Petersburg, the son of Karl Fedorovich Fetterlein, a German-language tutor, and Olga Fetterlein, née Meier. He studied a variety of eastern languages at the University of St Petersburg, graduating in 1894. On 25 November 1896 he joined the Ministry of Foreign Affairs. He eventually became the chief cryptologist for the Tsar of Russia, holding the rank of "General-Admiral," an honorary title in Tsarist Russia. During World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

, he was known for a time as Ernst Popov as his German-derived name could have drawn unwanted attention. Amongst others, he solved German, Austrian and British codes.

Upon the Russian Revolution of 1917
Russian Revolution of 1917
The Russian Revolution is the collective term for a series of revolutions in Russia in 1917, which destroyed the Tsarist autocracy and led to the creation of the Soviet Union. The Tsar was deposed and replaced by a provisional government in the first revolution of February 1917...

, he fled to Western Europe with his wife on board a Swedish ship, narrowly evading capture. He contacted the British and French intelligence organisations, offering to work for whoever would pay him the most, which was apparently the British, as he was recruited to Room 40
Room 40
In the history of Cryptanalysis, Room 40 was the section in the Admiralty most identified with the British cryptoanalysis effort during the First World War.Room 40 was formed in October 1914, shortly after the start of the war...

 in June 1918 to work on Georgian, Austrian and Bolshevik codes. After the end of World War I, he worked for the successor to Room 40, the Government Code and Cypher School (GC&CS), becoming a senior assistant on 17 December 1919. During this time he worked on Soviet Communist traffic. He was thought well of by his colleagues, one of whom wrote, "He was a brilliant cryptographer. On book cipher and anything else where insight was vital he was quite the best. He was a fine linguist and would usually get an answer no matter the language." He retired in 1938. His brother, P. K. Fetterlein, also worked for GC&CS.

Fetterlein came out of retirement during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

 to assist GC&CS's diplomatic section at Berkeley Street. He worked on "Floradora
Floradora
"Floradora", also called "Keyword," was a doubly enciphered diplomatic code used by the Germans during the Second World War. The Allies used tabulating equipment, created by IBM, to break the code over period of more than a year in 1941 and 1942....

", a German diplomatic code .
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK