Signals Intelligence in Modern History - World War II

World War II

A true world war, SIGINT still tended to be separate in the various theaters. Communications security, on the part of the Allies, was more centralized. Given that there were three major Axis powers, each primarily operating in a subset of the theaters, it is convenient to look at SIGINT from a primarily theater standpoint. From the Allied perspective, the critical theater-level perspectives were the Ultra SIGINT against the Germans in the European theater (including the Battle of the Atlantic, the Mediterranean Theater of Operations, and MAGIC against the Japanese in the Pacific Theater and the China-Burma-India theater. Germany enjoyed some SIGINT success against the Allies, especially with the Merchant Code and, early in the war, reading American attaché traffic. Japan was the least effective of the major powers in SIGINT. In addition to the official Allies and Axis battle of signals, there was a growing interest in Soviet espionage communications, which continued after the war.

British strategic stations were located at places including Darwin, Australia, and a Russian site. Major postwar stations include RAF Menwith Hill and Cyprus.