TheCodeBreakers
But what happened in February and July was
not necessarily what would happen in December.
During the summer and fall of 1941, the pressure of events molded
America's two cryptanalytic agencies closer and closer to the form they
were to have on December 7. The Signal Intelligence Service, which had
181 officers, enlisted men, and civilians in Washington and 150 at
intercept stations in the field on Pearl Harbor Day, had been headed
since March by Lieutenant Colonel Rex W. Minckler, a career Signal
Corps officer. Friedman served as his chief technical assistant. S.I.S.
comprised the Signal Intelligence School, which trained Regular Army
and Reserve officers in cryptology, the 2nd Signal Service Company,
which staffed the intercept posts, and four Washington sections of the
S.I.S. proper: the A, or administrative, which also operated the tabulating
machinery; the B, or cryptanalytic; the c, or cryptographic, which
prepared new U.S
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