Invariably the target of hostile intelligence interest, cipher machines, code books, and other related signals equipment can provide an opportunity to read an adversary’s communications. The removal of a German code book from the German light cruiser Magdeburg, which ran aground in the Baltic in October 1914, enabled the British Admiralty to read much of the kaiser’s naval wireless traffic, thus tipping the war at sea in the Royal Navy’s favor, and the interception of the Zimmermann telegram in 1917 changed history by helping to bring the United States into the conflict. During World War II, cryptanalytical attacks on Japanese, German, and Italian cipher systems proved immeasurably valuable and played vital, if unpublicized, roles in the Battle of Midway, the North African campaign, and the Battle of the Atlantic fought against the U-boat wolf packs and in ensuring the success of the D-Day landings.
Accordingly, most countries take elaborate precautions to protect vaults containing “crypto” material and the personnel handling it. During the Cold War, the Central Intelligence Agency ran a highly secret unit, designated Staff D, that concentrated on the penetration of target crypto accommodation. Similarly, the Federal Bureau of Investigation concentrated on suborning Eastern Bloc cipher staff and gaining access to cipher spaces using “second-story men,” a euphemism for burglars. Few cases have reached the public domain, but the defection of Jozef Simonic, who left the Polish mission to the United Nations with a suitcase full of secret documents, and the similar case in 1958 of Frantisek Tisler, a cipher clerk based at the Czech
embassy in Washington, D.C., were disclosed eventually. However, such revelations may take years to emerge so as to prevent countermeasures being taken. Probably the most serious breach of cryptographic security took place between 1965 and 1983 when submariner John Walker sold American crypto secrets to the KGB and thereby compromised the movements of the United States Navy’s underwater fleet.