Spying in America: Espionage from the Revolutionary War to the Dawn of the Cold War

23. America's Counterespionage Weapon: Venona

173 America’s Counterespionage Weapon Venona I stood in the vestibule of the enemy’s house, having entered by stealth. Robert Lamphere, FBI liaison to the Venona Project, in his book The FBI–KGB War The story of American counterespionage in the years immediately after World War II is the story of the Venona Project.1 Ironically, Joseph Stalin himself was responsible for a project that led to the discovery of the most extensive spy network in American history. Stalin’s decision to sign a nonaggression pact with Adolph Hitler in 1939 not only drove American communists from the Communist Party but also jolted the US government. As a result, the FBI intensified its hunt for communists , and the army, which was responsible for signals intelligence, also took action. In a move that was to have a monumental impact on Soviet espionage, the US Army started collecting enciphered message traffic from Soviet diplomatic and trade missions in the United States. Long before the days of satellite communications, foreign missions used the commercial telephone lines of the host country to communicate their correspondence to their capitals. Like other embassies, the USSR’s diplomatic missions 23 174 The Golden Age of Soviet Espionage—the 1930s and 1940s encrypted these communications, and the unreadable Soviet messages simply stacked up on army desks for the next few years. HitlerviolatedthepactandinvadedRussiain1941,theJapaneseattacked Pearl Harbor in December of that same year, and the United States and USSR became wartime allies. The messages continued to pile up until rumblings of independent peace overtures by Stalin to Hitler prompted the army to attempt decryption of the traffic.2 A team of cryptographers labored in strict secrecy during the next two years on a seemingly impossible task in Arlington Hall, a girls’ school in suburban Virginia that had been converted into an army facility. The Soviets used a simple yet unbreakable encryption system of “onetime pads.” The system involved substituting random sets of numbers on the pads for the letters of the text. The sender and recipient had identical copies of the pad, and each used his copy to encrypt and decrypt messages. Although the army could intercept the encrypted messages, the random nature of the numbers made decryption impossible. At the same time the contribution of American cryptography to national security had progressed considerably since Elbridge Gerry, Samuel West, and Elisha Porter deciphered the letter proving Benjamin Church’s espionage in 1775. Meredith Gardner, a brilliant linguist, had already worked on the successful breaking of Japanese codes in the “Magic” project, and he was among the cryptographers assigned to tackle Venona, the code name for the Russian codebreaking task. The hours were long and the work unglamorous for Gardner and his colleagues as they labored to discern patterns among the incomprehensible jumble of numbers that could enable them to crack the code. A decisive breakthrough occurred in 1944, when Venona cryptographers discovered a gross mistake by the Soviets. Even the simplest mistake can be costly in espionage. A single error can compromise an entire operation, and there is no more glaring illustration of this in espionage history than the Soviet misstep with their encryption system in the early 1940s. Ironically, the sheer volume of intelligence activity was responsible for the mistake. The Soviets were collecting so much information that demand for one-time pads outpaced production. In 1942, someone in the NKVD simply made copies of pads and sent them out for reuse to overseas installations . The blunder negated the basic “one time” principle in the system.3 175 America’s Counterespionage Weapon • Venona The Venona team learned of the mistake by distinguishing patterns that showed separate messages had been enciphered using the same pad. Even with this breakthrough, the army code breakers were only able to decode portions of messages. Gardner and his colleagues began a slow and painstaking reconstruction of Soviet codes, and by the summer of 1946 Venona research had revealed that the traffic not only concerned diplomatic and trade issues but also Sovietintelligenceactivities.GardnermadeastartlingdiscoveryonDecember 20, 1946, ironically the twenty-ninth anniversary of the Soviet intelligence services. Officers of the MGB (Ministry of State Security, then the name of the Soviet security service) celebrated this anniversary around the world clinking vodka glasses in toasts, unaware that the Americans were tugging on the first threads that would unravel the greatest spy network in the history of the Soviet intelligence services. Gardner decoded a 1944 message...