Station HYPO

CDR Gresham, was the third commander to lead the Cryptologic Community and the inventor of the Navy’s first machine-generated cipher machine.  Commander Gresham’s biography follows:

Commander William “Pop” Fuller Gresham
United State Navy
1883 – 1935

A native of Jonesboro, Tennessee, William F. Gresham was born about 1883.  He entered the academy in 1905 and graduated with the class of 1908.  His nickname while at the Academy (and after) was “Pop.” In a span of 11 years he was promoted from Ensign to Lieutenant Commander.

While serving on SS AZTEC, a cargo ship (Armed Guards) during World War One, on April 1 1917 the ship was torpedoed off the coast of Ushant in France by the German U-boat SM U-46. 28 passengers were killed, including 10 American crew members. As the results of LT Gresham’s actions he was awarded the Navy Cross.  The citation reads:

“The President of the United States of America takes pleasure in presenting the Navy Cross to Lieutenant William Fuller Gresham, United States Navy, for exceptionally meritorious and distinguished service as Commanding Officer of the Armed Guard on S.S. AZTEC in an engagement with an enemy submarine during World War I. The report indicates that the men showed the proper zeal, and were well trained and efficient.”

On April 18, 1919, LCDR Gresham transferred to the West Coast in connection with the construction of the USS CRANE (DD 109), which had been launched July 4, 1918 by Bethlehem Shipbuilding Corp., San

Francisco, California. The ship was commissioned on April 18, 1919 with LCDR Gresham in command.

Clearing San Francisco on April 21, 1919, the USS CRANE arrived at Newport, Rhode Island on May 13. She sailed for duty in European waters on June 5, visiting ports in England and France and joining the escort for George Washington carrying President Woodrow Wilson to the peace conference. Returning to New York on July 27, the USS CRANE was assigned to the Pacific Fleet, and arrived at San Francisco on September 1. Here she participated in the Naval Review, during which she was visited by Secretary of the Navy Josephus Daniels on September 4.  After operations off the coast of Washington state the USS CRANE was placed in reserve at San Diego on January 26, 1920.

Following his assignment on USS CRANE, LCDR Gresham, served on USS BENHAM (DD 49) from June 1 1919 to December 10 1919.  After his time at sea he reported the Navy Department, Washington, D.C. on June 1921 and on July 1, 1921 he relieved CDR M.F. Draemel as the Officer-in-Charge, Code and Signal Section of Naval Communications System, (OP-18).  He remained in that position until he was relieved on July, 1 1922 by LCDR D.C. Godwin.

The Navy’s first machine-generated cipher machine.

Some naval cryptologic historians argue that it was the Naval Cipher Box, but an argument can also be made that it was the Communications Machine (CM),* invented in the early 1920s by Navy Lieutenant Commander William F. “Pop” Gresham. The CM was a mechanical cipher device based on a sliding alphabetic system. It was the first system that dispensed with a codebook. It became the standard navy cryptologic tool during the 1920s. Although it did require some hardware modifications later, it was essentially the Navy’s first high-command cipher.

NSA’s Center for Cryptologic History (CCH’s) intent in covering this invention is to showcase Army-Navy cryptologic cooperation during a time period when it was arguably non-existent. At the time, the Army’s primary cryptologic unit was MI-8 (a.k.a. the Cipher Bureau), headed by Herbert O. Yardley, arguably America’s pre-eminent cryptologist at the time. In fact, his influence was probably at its height, as his Cipher Bureau had just broken Japanese diplomatic codes that enabled the United States to out-negotiate the Japanese during the 1921-1922 Washington Naval Disarmament Conference.

The Navy, in comparison, had the Research Desk of its Code and Signal Section, headed by the above mentioned “Pop” Gresham. In July 1922, Gresham contacted Major Frank Moorman of the Army’s Military Intelligence Division in Washington to request his opinion of Gresham’s invention, enclosing samples of his encrypted messages along with the alphabets he designed for the device’s use. Moorman simply forwarded the request to Yardley.

Yardley provided his evaluation of the Gresham machine in a July 21, 1922, note to Moorman. He admitted that he had not yet had time to read the messages enciphered by Gresham. However, based on their appearance and the accepted Herbert Yardley codebreaking procedures of his day, he opined that the method of attack would essentially be the same as attacking a Bazeries Cylinder.** Yardley furthermore reasoned that since the rest of the world was already familiar with the Bazeries  Cylinder (the U.S. Army also used it at the time), Gresham’s new machine would logically be breakable by an adversary.

Could Yardley make Gresham’s device better? He told Moorman that “if Commander Gresham is really desirous of learning the strengths and weaknesses of his cipher, I would think that he should be willing to turn his machine over to us.” He offered to educate Gresham further about the Bazeries Cylinder, to include what his Cipher Bureau would do to protect codes during wartime. Yet he offered no guarantees of total invincibility for Gresham’s cipher. Yardley did acknowledge though that the Bazeries Cylinder provided security for a while because codebreaking was not a fast process.

Finally, Yardley, then New York City-based, offered to discuss the Gresham cipher in person with both Moorman and Gresham when he traveled to Washington, D.C. in early August. CCH, for the record, does not yet know if the meeting was ever held. CCH does presume though that the Gresham cipher evaluated by Yardley, because of the time line involved, was probably Gresham’s eventual CM invention.

As a historical note, the CM had a more well-known co-founder. When Gresham died in 1935, his widow made a claim for recompense. As Congress investigated the claim, Agnes Meyer Driscoll, the Navy’s principal civilian cryptanalyst for many years and Gresham’s underling at the time, claimed a share in the invention. She was successful to the point that both she and Mrs. Gresham received $15,000 for the invention in 1937.

* It was later known just as the “Cipher Machine”

** Named after the French military cryptologist Étienne Bazeries, the Bazeries Cylinder is essentially an improved version of the (Thomas) Jefferson Disk or wheel cipher, currently on display at the National Cryptologic Museum. Yardley, by the way, consistently dropped the “s” (Bazerie) in his correspondence with Moorman.

Sources:
Echoes of Our Past NCVA;
“Madame X: Agnes Meyer Driscoll and U.S. Naval Cryptology, 1919-1940,”
Cryptologic Almanac 50th Anniversary Series, DOCID: 3575740;
CCH internal source records, e.g., AMD References in Holtwick’s Naval Security Group History of World War II, SRH-355, Part 1;
Background information on Yardley, early Navy cryptologic organizations, and ciphers, Bazeries Cylinder and Jefferson Disk