An official website of the United States government
Here's how you know
A .gov website belongs to an official government organization in the United States.
A lock (lock ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

News | May 12, 2015

NSA Observes Armed Forces Week - Army and Navy

The men and women of the United States Armed Forces work tirelessly to protect and uphold the safety and freedom of the country and its citizens. Each service has uniquely contributed to the fields of intelligence and cryptology through technologic advancements, critical breakthroughs, and amazing discoveries.

This week, NSA/CSS will honor each service by highlighting significant cryptologic events of that service throughout our nation's history.


In the years immediately preceding America's entry into World War I, the Army took its first steps into the world of cryptology. A young Army officer, Capt. Parker Hitt, became interested in the subject while attending school at Fort Leavenworth, Kansas. After identifying issues within the Signal Corps cipher disk, he turned his attention to code solution. He later published the Manual for the Solution of Military Ciphers, the first book devoted to cryptology ever published in the United States.

After the outbreak of World War I, the Army activated the MI-8 branch to manage all cryptanalysis. This task was redirected back to the Signal Corps in 1929 under the responsibility of William F. Friedman, the head of the new Signal Intelligence Service (SIS). During the 1930s, the SIS developed an electromechanical cipher that had unparalleled security. This cipher was modified into the SIGABA and became the backbone of high-level U.S. communications during World War II.

At the end of World War II, the Army activated the Army Security Agency (ASA) on September 15, 1945, to exercise command and control over all signals intelligence and communications security. Its unique command structure and centralized control over the Army's cryptologic functions set it apart from other Army forces. During the late 1940s, part of the ASA was transferred to the Air Force, and the remaining functions formed the Armed Forces Security Agency which later evolved into NSA.

As of May 11, 2015, 50 soldiers have been honored on the NSA/CSS Cryptologic Memorial Wall in remembrance of those who gave their lives while "serving in silence" in the line of duty.

During the last 60-plus years, four Army generals have served as the Director of the National Security Agency (DIRNSA), and two generals as both DIRNSA and Chief of the Central Security Service (established in 1972).


In spring 1942, the Allied war effort in the Pacific was in a precarious state. Cmdr. Joseph Rochefort was in command of Station Hypo, the Navy's codebreaking organization at Pearl Harbor. Rochefort and his staff began to slowly make progress against JN-25, one of the many Japanese command codes that had proven so challenging to the Station Hypo team. (JN-25 was the Japanese Navy's operational code.) Before the attack on Pearl Harbor, only 10 to 15 percent of the code was being read. By June 1942, however, Rochefort's staff was able to make educated guesses regarding the Japanese Navy's crucial next move. Due to the cryptologic achievements of Rochefort and his staff, Adm. Chester W. Nimitz knew that the attack on Midway would commence on June 3. Armed with this crucial information, he was able to get his outgunned, but determined, forces in position in time. On June 4, the battle finally started. Gen. George Marshall, the U.S. Army Chief of Staff, said, "As a result of cryptanalysis, we were able to concentrate our limited forces to meet their naval advance on Midway when we otherwise would have been 3,000 miles out of place."

In early April 1943, Japan's Fleet Adm. Isoroku Yamamoto was intercepted in mid-air by American fighter pilots over open water and killed in a daring raid. On the morning of April 14, 1943, U.S. Naval Intelligence in Hawaii intercepted, decoded, and translated a message concerning the movements of Adm. Yamamoto and his plan to inspect the forward troops on Bougainville and Shortland Islands. The message read: "0600 depart Rabaul by medium attack plane (accompanied by six fighters)…" The rest of the message detailed the remainder of the admiral's trip. Adm. Nimitz ordered a strike, which was backed up by both U.S. Navy Secretary Frank Knox and President Franklin D. Roosevelt.

Other Navy accomplishments in cryptology include those of Grace Murray Hopper. While on active duty in the U.S. Navy, Hopper identified and named the first computer bug in 1947. Hopper is credited with popularizing the term "debugging" for fixing computer glitches (inspired by an actual moth removed from the Mark II computer). The U.S. Navy Arleigh Burke class guided-missile destroyer, USS Hopper (DDG-70), is named for her, as is the Cray XE6 "Hopper" supercomputer at the National Energy Research Scientific Computer Center.

In summer 2013, Fleet Cyber Command fought through an adversary intrusion into the Navy's unclassified network. Under a named operation, known as OPERATION ROLLING TIDE, U.S. Fleet Cyber Command drove out the intruder through exceptional collaboration with affected Navy leaders, U.S. Cyber Command, National Security Agency, Defense Information Systems Agency, and our fellow service cyber components.

As of May 11, 2015, 67 sailors have been honored on the NSA/CSS Cryptologic Memorial Wall in remembrance of those who gave their lives while "serving in silence" in the line of duty.

During the last 60 plus years, six Navy admirals, including Adm. Michael S. Rogers, have served as the Director of the National Security Agency (DIRNSA), and four admirals as both DIRNSA and Chief of the Central Security Service (established in 1972).