The U.S. Navy’s cryptology community has a fascinating history, full of mysterious stories of deciphering the most complicated of codes and solving seemingly impossible puzzles.
From the Civil War, when cryptologic personnel were called upon to protect the Navy’s signals from unauthorized use, to World War II, when the use of cryptology helped alter the course of the war in the Pacific, the highly specialized skills of cryptologists were in high demand then and continue to be a valuable asset to the Navy.
The origins of the cryptology community as we know it began nearly 80 years ago, hitting its stride during World War II.
How Cryptology Won World War II
The spring of 1942 found the U.S. in the throes of war with Japan. The Japanese navy’s plans for decimating the U.S. Navy’s Pacific Fleet and its allies were moving forward at a brisk pace, as the Japanese Empire racked up victory after victory. Adm. Isoroku Yamamoto, the mastermind behind the attacks against the U.S., had created a plan to put a quick end to the war by luring the U.S. Navy into a battle at Midway Island.
Adm. Chester Nimitz did not have the luxury of miscalculating Japan’s next move. According to a National Security Agency (NSA) article by Patrick D. Weadon, the U.S. Pacific Fleet had only three aircraft carriers, 45 fighting ships, and 25 submarines between the West Coast of the U.S. and Hawaii while the Japanese fleet remained largely untouched. As Nimitz would need crucial information regarding Japan’s movements to win not only the battle but also the war, he turned to the codebreakers of OP-20-G (Office of the Chief of Naval Operations (OPNAV), 20th Division of the Office of Naval Communications, G Section/Communications Security) to decipher the encrypted communications of the Japanese, namely, the JN [Japanese Navy]-25 code.
According to the NSA, the JN-25 code contained approximately 45,000 five-digit numbers, and each number stood for a word or phrase. The five-digit numbers were super-enciphered using an additive table for transmission. Mathematical analysis was used to strip off the additive, while usage patterns were analyzed over time, allowing for the meaning of the five-digit numbers to be determined. Due to the repetitive use of additive tables, progress was slow. At the same time, the repetitive nature of the code eventually enabled the cryptologists to make educated guesses about the movements of the Japanese Navy.
The codebreakers, who had been working on deciphering JN-25 even before Japan’s attack on Pearl Harbor, successfully cracked the code in May 1942. The team determined that the attack on Midway would begin on June 3rd, and armed with that critical information, Nimitz was able to formulate a plan to win the Battle of Midway.
The Battle of Midway is considered one of the major turning points in World War II which led to U.S. victory in the Pacific.
Several codebreakers are credited for the advancements in cryptology which helped win World War II, and also shaped cryptology as we know it today.
Laurance Safford, the Father of U.S. Navy Cryptology
Capt. Laurance Safford, known as the “father of U.S. Navy cryptology,” was a 1916 graduate of the U.S. Naval Academy and the driving force behind the naval cryptologic organization, which he established after World War I. In January 1924, he was tapped for a position in OP-20-G as head of research in the Code and Signal section. According to an article by the National Security Agency (NSA), his first assignment was to “exploit a Japanese naval codebook that had been filched from the Japanese consulate in New York.”
Safford’s efforts also produced a system of intercept stations, designed to intercept covert Japanese communications, which would prove to be a valuable commodity to the U.S. as war with Japan became a reality.
Safford was instrumental in the building of cryptographic machines — in the late 1930s, his collaboration with the U.S. Army’s Frank Rowlett resulted in SIGABA, known as CSP-888/889 in Navy circles. This particular cryptomachine, which resembled a typewriter, was designed to keep high-level communications secure. The machine fulfilled its purpose; it was never broken during World War II. Additionally, Safford headed up the mechanization of codebreaking operations, which saw IBM [International Business Machines Corporation] equipment added to cryptographic machines.
According to the NSA, Safford found “signs of war” in the “diplomatic traffic” of the Japanese and attempted to issue a warning in regard to Pearl Harbor several days before the attack occurred. His warning was dismissed by Rear Adm. Leigh Noyes, then director of naval communications.
The “father of U.S. Navy Cryptology” did not act alone in his cryptologic work. He assembled a team of gifted codebreakers, among them Agnes Meyer Driscoll, Capt. John Joseph Rochefort, Capt. Thomas H. Dyer, and Rear Adm. Edwin T. Layton.
Agnes Meyer Driscoll, Otherwise Known as Madame X
Agnes Meyer Driscoll, whose monikers included both Madame X and Miss Aggie, held a Bachelor of Arts degree in mathematics and physics from Ohio State University. She entered the Navy at the highest possible ranking — chief yeoman — at the end of World War I. Driscoll was assigned to the Code and Signal section of the Director of Naval Communications office and remained one of the leading cryptanalysts in the Navy until 1949.
Making waves from the beginning, Driscoll’s first days in the Code and Signal section saw her become a co-developer of the "CM," a U.S. Navy cipher machine. She briefly left the Navy to be a technical advisor at Hebern Electric Code Company, but returned two years later with knowledge of Hebern's advancements in rotor technology, which, according to an NSA article, would “affect machine cryptography for years to come.”
Fluent in the Japanese language, Driscoll began breaking Japan’s navy manual codes early in her 30-year career, beginning in the 1920s. In 1935, she spearheaded the attack on the ORANGE machine, also known as the Japanese M-1 cipher machine. This machine was used to encrypt messages of Japanese naval attachés worldwide.
By the time World War II was on the horizon, Driscoll had already made significant headway in the breaking of JN-25. Though her best-known work was with Japanese naval codes, she was also involved in the Navy's effort against the German naval machine called Enigma, an electro-mechanical rotor cipher machine — although this work was superceded by the U.S.-U.K. cryptologic exchanges in 1942-43. Her findings on JN-25, however, enabled the U.S. Navy to use the top-secret information against the Japanese for the entirety of the war in the Pacific.
Joseph Rochefort, Midway’s Cryptologic Hero
Captain Joseph John Rochefort bears one of the most famous names in the critical Battle of Midway and is widely recognized for the cryptologic support he provided to help the U.S. win in the Pacific.
Rochefort enlisted in the Navy in 1918 and received an ensign commission after graduating from Stevens Institute of Technology. Trained under both Safford and Driscoll in cryptanalytics, Rochefort was chosen to serve as the second chief of OP-20-G, the Department of Naval Communications’ newly formed cryptanalytic organization in 1926. In 1936, he began a two-year intelligence assignment in the Eleventh Naval District, located in San Diego.
Due to Rochefort’s expertise as a Japanese linguist, intelligence analyst, and cryptanalyst, he was hand-picked by Safford for the position of Officer-in-Charge (OIC) at Pearl Harbor’s Station Hypo, code name for the Combat Intelligence Unit and the administrative headquarters of the 14th Naval District. According to an article by Commander, Navy Installations Command (CNIC), Navy Region Hawaii, Hypo was responsible for collecting and analyzing Japanese radio signals so that the U.S. could keep an eye on the “expansionist designs of the Japanese Empire.”
Safford had tapped Rochefort to head up the efforts in breaking JN-25, giving him a “blank check” to acquire the best cryptanalysts in the Navy. According to the NSA, after the Japanese bombed Pearl Harbor, Rochefort and the Hypo unit were able to decode a sufficient amount of Japanese naval communications to “provide daily intelligence reports and assessments regarding Japanese force disposition and intentions.”
Rochefort's team of talented cryptanalysts, traffic analysts and linguists eventually broke JN-25, which greatly assisted the U.S. achieve victory in the Battle of Midway.
Capt. Thomas “Tommie” Dyer, the Father of Machine Cryptanalysis
A 1924 graduate of the Naval Academy, Capt. Thomas Dyer was a radio communications officer who led the team of codebreakers responsible for deciphering the vast majority of Japanese naval communications during World War II’s Pacific campaign. He played a critical role in the success of the Battle of Midway.
In May 1931, Dyer was assigned to OP-20-G. Like Rochefort before him, he was trained by Driscoll. He became known as the “father of machine cryptanalysis” when he began using IBM tabulators to streamline the process of sorting through the numerous possible solutions when breaking codes and ciphers.
Dyer arrived at Station Hypo in July 1936, when it was still known as 14th Naval District's Fleet Radio Unit. During his assignment at Hypo, he formed the Communications Intelligence Unit in Pearl Harbor, which had both intercept and direction-finding stations located at Heiia and Wahiawa.
When Rochefort became OIC at Station Hypo in 1941, Dyer was his right-hand man, serving as both assistant OIC and chief cryptanalyst. Dyer was also the supervisor of the team; under his leadership, the Hypo unit was able to create an intricately detailed picture of the occupation plan the Japanese intended to execute. This allowed Adm. Nimitz’s intelligence officer to make an accurate prediction of where and when the Japanese would strike, ultimately leading to success in the Battle of Midway.
Rear Admiral Edwin Layton
Rear Adm. Edwin Layton was also a 1924 graduate of the Naval Academy. Upon receiving his commission, he was sent to the Pacific where he served five years on the USS West Virginia (BB-48) and USS Chase (DD-323). A gifted linguist, Layton was one of only a few naval officers chosen to learn the Japanese language in 1929.
In the 1930s, Layton was assigned to the Navy Department’s Office of Intelligence twice before returning to Tokyo in 1937, where he would spend two years at the American Embassy as assistant naval attaché.
Layton was Combat Intelligence Officer on the staff of Adm. Husband E. Kimmel, Commander-in-Chief of the United States Fleet at Pearl Harbor when the U.S. declared war on Japan. He was responsible for all intelligence in the Pacific Ocean area. According to a Naval War College (NWC) article, he and his team had the important task of evaluating all of the capabilities and intentions of the Japanese — naval, air and sea.
The information that Layton’s team gathered was crucial in the planning of naval campaigns against Japan and is widely regarded as one of the major keys to victory in the Pacific. Layton would later co-author a book about his experiences: And I Was There: Pearl Harbor and Midway — Breaking the Secrets.
The Modern Cryptology Community
Today’s cryptology community includes leading officers such as Vice Admiral Jan E. Tighe, commander, U.S. Fleet Cyber Command, commander, U.S. 10th Fleet; Darren Sawyer, senior advisor for Navy Intelligence Enterprise Information Technology (OPNAV N2/N6); and Rear Adm. Elizabeth Train, director, National Maritime Intelligence Integration Office commander, Office of Naval Intelligence.
Vice Adm. Tighe, an Information Warfare (formerly Cryptologic Officer) and Information Dominance Warfare Officer, recently told CHIPS, “I am lucky to be in such a fascinating and important field — our Navy and our country have a storied history of codebreaking in defense of the nation. Today’s team proudly and skillfully carries on that legacy. We have a diverse group of warfighters who represent a cross section of our country and all of its wonderful diversity.”
Information Warfare Officers (IW) and Cryptologic Technicians (CT), as they are presently known, are now under the umbrella of the Information Dominance Corps. They have continued to be an integral part of the Navy, at home and abroad, diligently serving in peacetime and war.
Though threats to cyberspace are something that yesterday’s codebreakers didn’t have to contend with, the core practices of cryptology haven’t changed much since World War II. Today’s codebreakers are also fluent in an array of foreign languages, and use the latest technology to scrutinize encrypted communications to uncover hidden messages, utilize asymmetric capabilities in the physical domains as well as in cyberspace and the electromagnetic spectrum, collect and analyze intelligence, safeguard networks, and confuse enemy radars.
Cryptology also continues to be “cloaked in secrecy” — as Navy Recruiting Command’s Enlisted Information Dominance Corps Branch Lead, Chief Cryptologic Technician (Interpretative) Steven Barbee said, "If you conduct an Internet search on Navy intelligence you won't find anything about cryptology but rather about our intelligence specialists. Many recruiters do not know anything themselves about the CT ratings or the jobs associated with these ratings."
Looking for the Future Generation of Codebreakers
Is there a new Agnes Driscoll or Joseph Rochefort just waiting to be discovered, perhaps via social media?
On May 1, the Navy’s crack-the-code cryptology game known as Project Architeuthis was launched on the U.S. Navy Cryptography & Technology’s Facebook page by the Navy Recruiting Command (NRC) to attract recruits to the CT community. NRC partnered with its advertising agency, Lowe Campbell-Ewald (LCE), to create the first of its kind alternate reality game (ARG) for social media.
The game is unique in that it was specifically created to raise awareness and interest in a particular Navy program to demonstrate that the Navy provides opportunities to explore a love of information technology, electronics, cryptology and communications.
NRC’s Marketing and Plans Division member Sean Forbes said of the game, "The plot of Project Architeuthis challenges intelligent, problem-solving individuals. The goal is to track down a mysterious enemy who has captured the chief architect of a top-secret weapon in order to build their own."
The name “Project Architeuthis” is nearly as mysterious as the puzzles that it asked codebreakers to solve. The elusive architeuthis, also known as giant squid, is a creature that dwells deep within the ocean’s secret, shadowy depths.
The ARG, which wrapped up on May 20, told its participants to “solve the puzzles, save your shipmates” and involved codebreaking to rescue its fictional characters, Dirk and Maria, from an enemy who sought to exploit their knowledge. New puzzles were added each day, adding layers to the story and providing clues to participants to help them solve the puzzles.
The layered approach kept participants on their toes. "Previously, we've posted puzzles, riddles and challenges to the U.S. Navy Cryptography & Technology Facebook page and users were able to solve them in about five minutes," Forbes said. "So we learned we really needed to step up our game."
According to Forbes, Project Architeuthis was formed not only to create awareness and attract potential shipmates, but also to leave participants with a favorable image of the Navy — and codebreaking.
To see the game winners, go to U.S. Navy Cryptography & Technology’s Facebook page.
FOR MORE INFORMATION
The Course to Midway
Navy Information Warfare/Cryptology Community Celebrates 77th Anniversary
US Navy Cryptology & Technology