The first twenty years of Elizebeth Friedman’s career as a cryptographer took her to a private research lab, the US Army and Navy, and the Department of the Treasury’s many law enforcement agencies. The start of the Second World War in Europe brought new challenges, starting with the preservation of American neutrality.
With the Coast Guard
The Coast Guard Cryptanalytic Unit began monitoring messages connected to foreign exchange for the Money Stabilization Board in 1938, watching for signs of imminent hostilities so the Board could freeze the funds of the belligerents. Starting in 1939 they also began picking up coded transmissions connected with the two sides. A presidential memorandum gave responsibility for espionage, counterespionage, and sabotage cases to the FBI, but when the Coast Guard turned their intercepts over to the FBI the FBI asked the Coast Guard cryptanalytic unit to solve the codes. The FBI was a relative latecomer to the code-breaking business, having only hired its full full-time cryptanalyst in October 1939. It leaned on the Coast Guard for cryptographic support. The first chief of its cryptanalytic section, W.G.B. Blackburn, was trained by Elizebeth Friedman.
Once the United States entered the war, cryptanalysis began to look like something of a free for all. In addition to the Army, Navy, Coast Guard, and FBI operations, the Office of Censorship, Federal Communications Commission, Weather Bureau, and Office of the Coordinator of Information (the future Office of Strategic Services) all announced that were setting up their own cryptanalysis programs. Thankfully, within about seven months all involved had agreed to centralize code-breaking activities in the Army, Navy (including the Coast Guard), and FBI. The division of labor split clandestine radio messages in the Western Hemisphere between the Navy and FBI and gave the former responsibility for intercepting clandestine communications in the rest of the world. The Coast Guard cryptanalytic unit, now a sub-section of the Navy’s code-breaking division (OP-20-G) continued to focus on these secret messages. It also grew, first to twelve and then to twenty-three people. Elizebeth Friedman was not the commander of the Coast Guard cryptanalytic unit. That role belonged to a commissioned officer, L.T. Jones. After the war she described herself, with perhaps an excess of modesty, as “just one of the workers.”
The ciphers that reached the Coast Guard for decryption came from both individual agents working in secret and substantial radio stations operating out of German embassies. Messages were enciphered using a range of classic ciphers that either replaced (in a substitution cipher) or shifted around (in a transposition cipher) the letters in the message. Most agents were using hand ciphers, in which the message is enciphered using pen and paper rather than a mechanical device. A few used a mechanical device, the Kryha machine, which created a shifting substitution cipher. Agents in Argentina used the same Enigma machine that the German army and navy used to protect their messages (and whose decryption was most recently depicted, with substantial inaccuracies, in The Imitation Game). The Coast Guard was able to use intercepted messages to reverse engineer the wiring that scrambled each letter in the simpler, commercial Enigma machine – those messages turned out to be from the Swiss army. According to NSA historian David P. Mowry this was “the first instance of Enigma wiring recovery in the United States.” Then, with the assistance of British techniques, the Coast Guard team was also able to decrypt messages sent on the Enigma between Argentina and Berlin.
The traffic that the Coast Guard’s code-breaking operation intercepted was never critical to the war effort. Interviewed after the war, Friedman herself suggested that the unit could probably have been better used on other material, rather than working the problem “to the point of overkill” (in her interviewer’s words). Mowry, who wrote a Top Secret history of the topic for the NSA, judged that the US effort to decrypt German clandestine transmissions from the Western Hemisphere had little or no impact on the conduct of the war. Still, American cryptanalysis ensured that nothing snuck up on US operations. Nor was the Coast Guard work Elizebeth Friedman’s only contribution to the war effort. When the Office of the Coordinator of Information was created, she also developed its first code systems.
A Long and Varied Career
Cryptography has such a long history that it’s sometimes hard to remember that large government code-breaking organizations are such a new development. Elizebeth Friedman entered the field at the moment those organizations were being created. Without schools or training programs, cryptographers were few and far between. While her husband spent his career with the Army and the National Security Agency, creating the institutions that would perpetuate the government’s cryptanalytic programs, Elizebeth worked far and wide. Between when she left Riverside Laboratories and when she retired from government service, she worked for or taught at seven of the sixteen members of the current US Intelligence Community (Army, Navy, Coast Guard, Central Intelligence Agency, Department of the Treasury, Federal Bureau of Investigation, and National Security Agency). Her career was not only remarkable for its scope but also probably unrepeatable. By the time she retired, these agencies were on their way towards the extensive permanent organizations that exist today. Retirement was also not the end of Elizebeth’s involvement in cryptography. She consulted for the International Monetary Fund on creating that agency’s secure communications and published a book, The Shakespearian Ciphers Examined (with William Friedman), on their work studying Shakespeare’s works for hidden codes.
Source Notes: The NSA’s history office commissioned several relevant histories as part of its Second World War series. One by Robert Louis Benson, The History of U.S. Communication Intelligence during World War II: Policy and Administration, covers the various organizations; two others, both by David P. Mowry, cover German Clandestine Activities in South American in World War II and The Cryptology of the German Intelligence Services (available amalgamated here). Some of Friedman’s own comments in an oral history interview with Benson (online here) were also useful.