Joseph Finnegan (August 12, 1905 – September 8, 1980) was a

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

linguist Linguistics is the scientific study of human language. It is called a scientific study because it entails a comprehensive, systematic, objective, and precise analysis of all aspects of language, particularly its nature and structure. Linguis ...

and

cryptanalyst Cryptanalysis (from the Greek ''kryptós'', "hidden", and ''analýein'', "to analyze") refers to the process of analyzing information systems in order to understand hidden aspects of the systems. Cryptanalysis is used to breach cryptographic sec ...

with

Station Hypo Station , also known as Fleet Radio Unit Pacific () was the United States Navy signals monitoring and cryptographic intelligence unit in Hawaii during World War II. It was one of two major Allied signals intelligence units, called Fleet Radio Units ...

during the

Second World War World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

Early life and education

Joseph Finnegan was born and raised in

Dorchester, Massachusetts Dorchester (colloquially referred to as Dot) is a Boston neighborhood comprising more than in the City of Boston, Massachusetts, United States. Originally, Dorchester was a separate town, founded by Puritans who emigrated in 1630 from Dorchester ...

. His father was Peter Joseph Finnegan and his mother was the former Marion Catherine Connor. Joseph Finnegan had a brother and four sisters. He enlisted in the U.S. Navy in 1922 as an apprentice seaman and later served as a yeoman third class on the battleship . Finnegan attended the Naval Academy preparatory school in

San Diego, California San Diego ( , ; ) is a city on the Pacific Ocean coast of Southern California located immediately adjacent to the Mexico–United States border. With a 2020 population of 1,386,932, it is the eighth most populous city in the United States ...

, and finished first in his class. Appointed to the

United States Naval Academy The United States Naval Academy (US Naval Academy, USNA, or Navy) is a federal service academy in Annapolis, Maryland. It was established on 10 October 1845 during the tenure of George Bancroft as Secretary of the Navy. The Naval Academy ...

, he graduated fifteenth in a class of 153 in 1928. Finnegan served as an ensign on the battleship from August 1928 to November 1930. Promoted to lieutenant (junior grade) in 1931, he helped commission the heavy cruiser in February 1934 and then served as her radio officer.Maffeo, p. 238

Retrieved 2020-02-07. Later in 1934, Finnegan was selected by the

Office of Naval Intelligence The Office of Naval Intelligence (ONI) is the military intelligence agency of the United States Navy. Established in 1882 primarily to advance the Navy's modernization efforts, it is the oldest member of the U.S. Intelligence Community and serves ...

to attend three years of full immersion

Japanese language is spoken natively by about 128 million people, primarily by Japanese people and primarily in Japan, the only country where it is the national language. Japanese belongs to the Japonic or Japanese- Ryukyuan language family. There have been ma ...

and culture training in

Tokyo Tokyo (; ja, 東京, , ), officially the Tokyo Metropolis ( ja, 東京都, label=none, ), is the capital and largest city of Japan. Formerly known as Edo, its metropolitan area () is the most populous in the world, with an estimated 37.468 ...

. While still there, he was promoted to Lieutenant in 1936. After completing his training, Finnegan was assigned to

Station CAST Station CAST was the United States Navy signals monitoring and cryptographic intelligence fleet radio unit at Cavite Navy Yard in the Philippines, until Cavite was captured by the Japanese forces in 1942, during World War II. It was an important p ...

in the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

in October 1937. He served there until relieved by Captain Alva Lasswell in September 1938.

War contribution

In 2002,

Tex Biard Captain Forrest Rosecrans "Tex" Biard (December 21, 1912 in Bonham, Texas – November 2, 2009) was an American linguist in the U.S. Navy codebreaking organization during the Second World War. A pre-war student of Japanese, Biard's translation ...

described Finnegan as "intuitive" and "brilliant", and second only to Station Hypo chief Joseph J. Rochefort, saying that Finnegan's survival of the

bombing A bomb is an explosive weapon that uses the exothermic reaction of an explosive material to provide an extremely sudden and violent release of energy. Detonations inflict damage principally through ground- and atmosphere-transmitted mechanica ...

of the '' USS Tennessee'' was a "fatal mistake" on the part of the

Japanese Japanese may refer to: * Something from or related to Japan, an island country in East Asia * Japanese language, spoken mainly in Japan * Japanese people, the ethnic group that identifies with Japan through ancestry or culture ** Japanese diaspor ...

, and that Finnegan's survival "cost (the Japanese) the war."Transcript of Tex Biard's 2002 speech
at USSPennsylvania.org He was reattached to the Division of Naval Communications after the attack and promoted to Lieutenant Commander on January 1, 1942.

Edwin T. Layton Edwin Thomas Layton (April 7, 1903 – April 12, 1984) was a rear admiral in the United States Navy. Layton is most noted for his work as an intelligence officer before and during World War II. He was also the father of the historian Edwi ...

, in his book "''And I Was There: Pearl Harbor and Midway -- Breaking the Secrets''" (1985) recounts a tremendous effort by Finnegan on the Hypo team concerning the exact date on which the attack on Midway would occur. This involved the date-time groups in Japanese naval messages. Layton refers to the date-time data as being “superenciphered,” meaning that this data was preencoded even before it was added to the

JN-25 The vulnerability of Japanese naval codes and ciphers was crucial to the conduct of World War II, and had an important influence on foreign relations between Japan and the west in the years leading up to the war as well. Every Japanese code was e ...

cipher. When Hypo made their all-out effort to crack this, they started by searching the stacks of printouts and

punched cards A punched card (also punch card or punched-card) is a piece of stiff paper that holds digital data represented by the presence or absence of holes in predefined positions. Punched cards were once common in data processing applications or to d ...

for five-digit number sequences. Those they found were in low grade codes, a poor starting point, but a starting point. Layton describes this method as "involving a 12 x 31 (12 rows for months, 31 columns for day) garble check. The 31 kana apanese syllabic scriptsof the first row were A, I, U, E, O, KA, KI …………….HA, HI, HU, HE, HO. The second row was I, U, E, O ……………HE, HO, A; the third, U, E, O ……….HO, A, I, and so on, for 12 rows. At the left, representing the 12 months, was a column of 12 kana, different from those in the table – SA, AI, SU, SE, SO, TA, TI, TU, TE, TO, NA, NI (SA for January, NI for December). To encipher, for example 27 May, one picked the 5th line (May=SO), ran across to the twenty-seventh column, HA, and recorded the kana at that intersection, HO. The encipherment, then, was SO, HA, HO, the third kana providing the garble check." (Layton, pp. 427–428) Finnegan was promoted to Commander on September 15, 1942, and later promoted to Captain on March 25, 1945. He was awarded the

Legion of Merit The Legion of Merit (LOM) is a military award of the United States Armed Forces that is given for exceptionally meritorious conduct in the performance of outstanding services and achievements. The decoration is issued to members of the eight ...

for his

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

contributions.

Postwar career

Finnegan was credited with

Korean War , date = {{Ubl, 25 June 1950 – 27 July 1953 (''de facto'')({{Age in years, months, weeks and days, month1=6, day1=25, year1=1950, month2=7, day2=27, year2=1953), 25 June 1950 – present (''de jure'')({{Age in years, months, weeks a ...

service and retired from the Navy in January 1953 for medical reasons. He was buried at

Arlington National Cemetery Arlington National Cemetery is one of two national cemeteries run by the United States Army. Nearly 400,000 people are buried in its 639 acres (259 ha) in Arlington, Virginia. There are about 30 funerals conducted on weekdays and 7 held on Sa ...

on September 11, 1980.

References

External links

Find A Grave obituary
1905 births 1980 deaths People from Dorchester, Massachusetts United States Navy captains United States Naval Academy alumni 20th-century American naval officers American cryptographers Intelligence analysts Pre-computer cryptographers United States Navy personnel of World War II Burials at Arlington National Cemetery United States Navy personnel of the Korean War Linguists from the United States {{US-linguist-stub