Abraham Sinkov Dr . Abraham Sinkov ( 1907 – 1998 ) was a US cryptanalyst . Biography . Sinkov , the son of immigrants from Russia , was born in Philadelphia , but grew up in Brooklyn . After graduating from Boys High School — what today would be called a " magnet school " – he took his B . S . in mathematics from City College of New York . ( By coincidence , one of his close friends at Boys High and CCNY was Solomon Kullback ) . Mr . Sinkov taught in New York City schools but was unhappy with the working conditions and anxious to use his mathematics knowledge in practical ways . Early career . The opportunity for a career change came in 1930 . Sinkov and Kullback took the Civil Service examination and placed high . Both received mysterious letters from Washington asking about their knowledge of foreign languages . Sinkov knew French and Kullback , Spanish . This was acceptable to their prospective employer , and they were offered positions as junior cryptanalysts . Although neither was quite certain what a cryptanalyst did , they accepted . The small Signals Intelligence Service ( SIS ) organization ( Sinkov and Kullback were the third and fourth employees there ) had the primary mission of compiling codes and ciphers for use by the U . S . Army . Its secondary task was to attempt to solve selected foreign codes and ciphers — this was not necessarily done for intelligence purposes but to keep the cryptanalysts abreast of new developments in the field . William Friedman put his new employees through a rigorous course of study of his own design in cryptology , bringing them to high levels of skill in making and breaking codes and ciphers . Friedman also encouraged other self - improvement endeavors : his employees trained summers at a camp at Ft . Meade to earn commissions in the military reserves . Both Sinkov and Kullback also went on to receive doctorates in mathematics . Sinkov received his PhD in mathematics in 1933 from The George Washington University . In 1936 , Dr . Sinkov was assigned to the Panama Canal Zone , where he established the U . S . Army ' s first permanent intercept site outside the continental United States . WWII . SIS grew slowly throughout the early 1930s . However , successes against Japan ese diplomatic machine systems after 1935 provided the U . S . government with critical information during a series of crises . This success had practical consequences for SIS , as well . For the first time , SIS began to garner respect from its military superiors . Once the military understood that this small organization could read sensitive messages from a potential adversary , the Signal Corps increased the SIS budget and authorized increased hiring of cryptanalysts . In 1940 , even though the United States was not officially a combatant , the U . S . and Britain initiated exchanges of technical material . Included in this was a cautious sharing of cryptologic information : the British in stages revealed the extent of their considerable success against high - level German systems , the U . S . its equivalent success against Japanese . This led to an unprecedented level of cooperation in COMINT between the two countries during the war , resulting in more personnel , bigger budgets , and a wider range of activities for the organization . In January 1941 , while Britain battled Nazi Germany but nearly a year before the United States entered the Second World War , Captain Sinkov was selected as a member of a delegation to the United Kingdom for initial sharing of information about the two countries ' respective cryptologic programs . The delegation returned in April with mixed results to report . Sinkov and his colleagues had been shown Bletchley Park , the secret headquarters for British cryptology , and exchanged information on German and Japanese systems . It is still unclear how much the American delegation was told about British success against the German Enigma machine , but Sinkov later recalled that they were told about the Enigma problem only a short while before the delegation was to leave , and that details were sketchy . Nevertheless , the mission to the UK was a success overall and helped give US - UK cryptologic relations a strong practical foundation . After the Japanese attack on Pearl Harbor on December 7 , 1941 , the Japanese also attacked the Philippine Islands . General Douglas MacArthur had been ordered to leave the Philippines and re - establish U . S . Army headquarters in Australia , from whence counterattacks might be launched . MacArthur recognized the need for cryptologic support , thus , on 15 April 1942 , he established the Central Bureau ( CBB ) , cobbling it together from refugee elements of American cryptologists evacuated from the Philippines , Australian cryptologists , and other Allied contingents . CBB began in Melbourne , then moved to Brisbane . In July 1942 , by now major Sinkov arrived in Melbourne as commander of the American detachment at Central Bureau . The Director of CBB on paper was General Spencer B . Akin , MacArthur ' s chief signal officer , but General Akin in practice seldom visited the organization . He had worked with Sinkov in Washington and in Panama , and confidently left CBB operations under his control . Dr . Sinkov , who demonstrated strong organizational and leadership qualities in addition to his mathematics skills , brought this group of Americans and Australians — representing also different military services from their countries — into a cohesive unit . CBB quickly became a trusted producer of Signals Intelligence ( SIGINT ) for MacArthur and his senior commanders . This SIGINT enabled consistent success in the air war against the Japanese and allowed MacArthur to win some stunning victories in the ground campaign in New Guinea and the Philippines . Post - war . After the war , Sinkov rejoined SIS , now renamed the Army Security Agency , and , in 1949 , when the Armed Forces Security Agency ( AFSA ) – the first centralized cryptologic organization in the United States — was formed , Sinkov became chief of the Communications Security program . He remained in this position as AFSA made the transition into the National Security Agency . In 1954 , Dr . Sinkov became the second NSA official to attend the National War College ( the first was Dr . Louis Tordella ) . Upon his return , he became Deputy Director for Production , effectively swapping jobs with his old colleague Frank Rowlett . Dr . Sinkov retired from NSA in 1962 . In 1966 , he wrote " Elementary Cryptanalysis : A Mathematical Approach " . Published by the Mathematical Association of America , it was one of the first books on the subject available to the general public . Retirement . Dr . Abraham Sinkov lived in retirement in Arizona after two careers , 32 years in NSA ( and its predecessors ) , followed by an appointment as a professor of mathematics at Arizona State University . Hall of fame . Colonel Sinkov is a member of the Military Intelligence Hall of Fame .