Information Dominance Corps Newsletter - Navy Cryptologic ...

Information Dominance Corps
Newsletter
A Publication from the
Deputy Chief of Naval Operations for Information Dominance
May 2012
This month’s focus:
BATTLE OF MIDWAY
IN THIS ISSUE:
l From the DCNO
l How Cryptology
enabled the
United States to
turn the tide in the
Pacific War
l Information
Superiority:
Paving the Way
for Victory at the
Battle of Midway
Information Dominance Corps –
This year the Navy observes the 70th anniversary of the Battle of Midway, which
occurred June 4–7, 1942. Battle of Midway commemorations will be held across the
country to include official ceremonies at the U.S. Navy Memorial in Washington, DC
and major events in Hawaii. In what is regarded as the turning point in the Pacific
theater of operations in World War II, U.S. Navy carrier strike forces augmented by
shore-based bombers and torpedo planes decisively defeated an Imperial Japanese navy
carrier task force. These actions prevented Japanese forces from capturing Midway
Island and marked the dawn of the U.S. Navy’s global prominence.
Information Dominance at Midway: Key to Admiral Nimitz’s decision to engage
the Japanese at Midway were the seminal efforts of the U.S. Navy’s code breakers, who not only provided
insight into Admiral Yamamoto’s intentions, but revealed where and when his carriers would focus their
attack. This highly skilled and knowledgeable group decrypted the Japanese Navy’s operational code and
delivered timely, actionable information that allowed Nimitz to ambush Yamamoto’s force. Led by Admiral
Nimitz’s Fleet Intelligence Officer, Captain Edwin Layton, and his Fleet Cryptologist, Commander Joe
Rochefort, these unknown and unheralded specialists enabled an enhanced awareness of the Midway
battlespace that culminated in Nimitz’s superior decisions. In many ways they pioneered Information
Dominance. This special edition of the Newsletter revisits the Midway story from two directions. In the first
article, Curator of the National Cryptologic Museum, Mr. Patrick Weadon, recounts the history of the Battle
and the contributions of our IDC predecessors. In the second, N2/N6’s Bob Huddleston relates Midway’s
lessons to our mission today.
Summer IDC Leadership Evolutions: As mentioned in our April edition, RADM Dave Titley
assumed duties as the Assistant Deputy Chief of Naval Operations (A/DCNO) in February. With over
32 years of active service, Admiral Titley will be piped over the side on 15 June, leaving an extraordinary
record of Naval Service and professional achievement. I have selected a highly qualified member of the
Senior Executive Service (SES) for the vacant A/DCNO position. As soon as the associated hiring actions
are completed, I will formally announce the new A/DCNO. Regretfully, the Deputy Director of Naval
Intelligence (DDNI), Mr. Mark Clark, is resigning from the civil service and will depart the staff on 8 June.
Mark has been the intellectual heart and soul of Naval Intelligence for the last few years, a true professional
if ever there was one. In July, RDML Diane Webber, Director, Communications and Networks Division
here at OPNAV will detach for duty at Fleet Forces Command/TENTH Fleet where she will relieve RDML
Matt Kohler as Deputy Commander. RDML Kohler will then report to OPNAV N2/N6 as Director,
Intelligence Operations, serving as the interim DDNI until a qualified senior civilian can be hired behind
Mr. Clark. Recently-hired SES Mr. Matt Swartz will relieve RDML Webber in N2/N6. In August, RADM
(Sel) Jon White will report to OPNAV as Oceanographer of the Navy and Director of Oceanography, Space
and Maritime Domain Awareness. RADM (sel) White will be relieved as Commander, Naval Meteorology
and Oceanography Command by RDML (sel) Brian Brown. Also in August, RDML Norm Hayes will
report to N2/N6 from EUCOM, serving in a Special Assistant role. Lastly, I want to acknowledge the
IDC’s newest flag officer selections, RDML (Sel) Brian Brown and RDML (Sel) Bruce Loveless. Sincere
congratulations and best of luck from the entire IDC!
Thank you again for your continued hard work in support of the Navy and the Nation, and for those of you
deployed around the globe, know that we deeply appreciate your service. As always...keep smiling!
Kendall Card
Vice Admiral, U.S. Navy
Deputy Chief of Naval Operations for Information Dominance

How Cryptology enabled the United States to
turn the tide in the Pacific War.
by Patrick D. Weadon
Courtesy of the National Security Agency
Reprinted with permission
This month’s focus:
BATTLE OF MIDWAY
IN THIS ISSUE:
l From the DCNO
l How Cryptology
enabled the
United States to
turn the tide in the
Pacific War
l Information
Superiority:
Paving the Way
for Victory at the
Battle of Midway
2
In late spring of 1942, the Allied war effort in the Pacific was in a precarious
state. The combined elements of the Japanese Empire’s armed forces had
moved from victory to victory. The Pacific fleet, save for several aircraft
carriers, had been left in ruins. It appeared that Japan’s plans for reducing
American and Western hegemony in the Pacific would become a reality.
Admiral Yamamoto, the leader of Japan’s naval efforts in the early days of
the Pacific campaign, had promised that at the outbreak of hostilities he
would “run wild for a year,” but that he had “utterly no confidence for the
second or third year.” As a young naval officer, Yamamoto had traveled
extensively in the United States and was well aware of America’s industrial
capabilities. His goal was to force the U.S. to sue for peace before this
industrial might could be directed against Japan. With this goal in mind, he
sought to lure the American Navy into a decisive battle, in which it would be forced to deploy its
remaining assets, thus providing his forces an opportunity to administer one final knockout blow.
While Yamamoto plotted to bring a quick end to war in the Pacific Theater, the United States
Navy in the Pacific, led by Admiral Chester Nimitz, was desperately trying to anticipate
Japan’s next move. Nimitz, unlike his counterpart, had little room for error. At the time of the
battle, his 3 aircraft carriers, 45 fighting ships, and 25 submarines were all that lay between
Hawaii and the West Coast and a large Japanese Fleet that had yet to suffer a significant
defeat. It appeared that Nimitz would have one shot at the enemy. A miscalculation by Nimitz
on where Yamamoto would strike next would not only be disastrous, but also possibly fatal to
the Allied war effort in the Pacific.
Fleet Admiral
Chester Nimitz
In order to prevail, Nimitz had to have some sense of Japan’s
intentions. The task of obtaining the critical information required to
turn the tide in the Pacific fell to OP-20–G, the Navy radio intelligence
organization tasked with providing communications intelligence
on the Japanese Navy. Established in the early 1920s by Laurence
F. Safford, the “Father of Navy Cryptology,” OP-20–G was key to
Nimitz’s planning. In addition to his earlier cryptologic efforts, Safford
had played a major role in placing Commander Joseph Rochefort in
command of Station Hypo, the Navy’s codebreaking organization at
Pearl Harbor. Over a period of 18 years, OP-20-G had developed a
highly skilled group of officers and enlisted men.
In 1942 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. If it could be broken, Rochefort
would be able to provide Nimitz the information he needed to make wise and prudent decisions
concerning the dispersal of his precious naval assets.
The Breaking of JN-25
Breaking the Japanese code known to Americans as JN-25 was daunting. It consisted of
approximately 45,000 five-digit numbers, each number representing a word or phrase. For
transmission, the five-digit numbers were super-enciphered using an additive table. Breaking
the code meant using mathematical analysis to strip off the additive, then analyzing usage
patterns over time, determining the meaning of the five-digit numbers. This complex process
presented a challenge to the officers and men of Station Hypo, but Rochefort and his staff
were able to make progress because the system called for the repetitive use of the additive
Information Dominance Corps Newsletter / May 2012
Admiral
Yamamoto

tables. This increased the code’s vulnerability. Even so, the work was
painfully slow. Prior to the attack on Pearl Harbor, only 10% to 15%
of the code was being read. By June of 1942, however, Rochefort’s
staff was able to make educated guesses regarding the Japanese Navy’s
crucial next move.
This month’s focus:
BATTLE OF MIDWAY
IN THIS ISSUE:
l From the DCNO
l How Cryptology
enabled the
United States to
turn the tide in the
Pacific War
l Information
Superiority:
Paving the Way
for Victory at the
Battle of Midway
AF is Short of Water
In the spring of 1942, Japanese intercepts began
to make references to a pending operation in
Captain Rochefort which the objective was designated as “AF.”
Rochefort and Captain Edwin Layton, Nimitz’s
Fleet Intelligence Officer, believed “AF” might be Midway since they had
seen “A” designators assigned to locations in the Hawaiian Islands. Based
on the information available, logic dictated that Midway would be the
most probable place for the Japanese Navy to make its next move. Nimitz
however, could not rely on educated guesses.
Captain Layton
In an effort to alleviate any doubt, in mid-May the commanding officer
of the Midway installation was instructed to send a message in the clear indicating that the
installation’s water distillation plant had suffered serious damage and that fresh water was
needed immediately. Shortly after the transmission, an intercepted Japanese intelligence report
indicated that “AF is short of water.” Armed with this information, Nimitz began to draw up
plans to move his carriers to a point northeast of Midway where they would lie in wait. Once
positioned, they could stage a potentially decisive nautical ambush of Yamamoto’s massive
armada.
Due to the cryptologic achievements of Rochefort and his staff, Nimitz knew that the attack
on Midway would commence on 3 June. Armed with this crucial information, he was able to
get his outgunned but determined force in position in time. On 4 June the battle was finally
joined. The early stages of the conflict consisted of several courageous but ineffective attacks by
assorted Navy, Marine, and Army Air Corps units.
The tide turned however, at 10:20 a.m. when Lt. Commander Wayne McClusky’s Dauntless
dive bombers from the USS Enterprise appeared over the main body of the Japanese invasion
force. After a brief but effective attack, three of the four Japanese carriers, the Akagi, Soryu,
and Kaga were on fire and about to sink. Later that day, Navy dive bombers located and
attacked the Hiryu, the fourth and last major carrier in the invasion force, sending her, like the
previous three, to the bottom.
Final Thoughts
As in any great endeavor, luck did indeed play
a role, but Nimitz’s “Incredible Victory” was
no miracle. Gordon Prange, the distinguished
historian, noted that “Midway was a positive
American victory not merely the avoidance of
defeat.” General George Marshall, the U.S.
Army Chief of Staff, in his comments on the
victory, perhaps said it best, “ 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.”
VF-6 on board the USS Enterprise, January 1942
In the end, Yamamoto’s worst fears had become a reality. Due to an impressive mix of
leadership, determination and skill on the part of Admiral Nimitz, the officers and men of
Station Hypo, and the pilots, soldiers, sailors and marines who carried the fight to the enemy,
Japan would be on the defensive for the rest of the war. The Rising Sun of Dai Nippon, which
had shone so brightly for so many months, was beginning to set.
3
Photo Credits:
Admiral Yamamoto Japanese Government/All other photos U.S. Naval Historical Center
Information Dominance Corps Newsletter / May 2012

Information Superiority: Paving the Way for
Victory at the Battle of Midway
by Mr. Robert Huddleston
This month’s focus:
BATTLE OF MIDWAY
IN THIS ISSUE:
l From the DCNO
l How Cryptology
enabled the
United States to
turn the tide in the
Pacific War
l Information
Superiority:
Paving the Way
for Victory at the
Battle of Midway
Superior weapons and mass are highly valued in warfare but alone cannot guarantee
victory. For commanders lacking information superiority, victory can be elusive. Lessons
from history tell us that even an outgunned force holding a superior understanding of the
battlespace and the inner workings of the enemy can achieve victory, regardless of the ordersof-battle.
The Battle of Midway in June 1942 was one such lesson. Events leading to that
fateful clash, at that particular time, and in that small corner of the Pacific Ocean did not
unfold by happenstance. Armed with a rudimentary understanding of the Japanese Navy
code uncovered by U.S. Navy code breakers, Admiral Nimitz boldly orchestrated an attack
against a larger Japanese fleet of aircraft carriers and battleships known to be sailing towards
Midway. Risking his last three frontline carriers in a high-stakes gamble, Nimitz knew a
U.S. Navy defeat would have opened the entire Pacific to the Japanese Navy, jeopardizing
the overall U.S. war effort. To help even the odds at Midway, Nimitz banked on the Pacific
Fleet’s information edge over the inbound Japanese fleet.
In the end, the U.S. Navy victory at Midway was achieved by determined and fearless
aviators who triumphed in the face of formidable ship-based anti-aircraft artillery and an
overwhelming number of Japanese fighter aircraft, many of which were superior to our
own. In the very beginning, however, the Battle of Midway was presaged and enabled by
U.S. Navy information experts working in the shadows to decipher, understand and predict
Admiral Yamamoto’s next steps and to locate the fast-moving Japanese fleet. Just knowing
the Japanese carriers were en route Midway enabled tactical positioning of the U.S. Navy
carriers for attack. Understanding the local sea state, winds and cloud cover enhanced
planning for surveillance and attack missions. Flying long-range surveillance of the main
body of the Japanese fleet far from our own carriers helped coordinate distant land- and
sea-based aerial attacks. Sending tactical orders and attack plans secretly and assuredly
across the vast distances of the Pacific synchronized operations. In essence, the informational
groundwork paving the way for a potential U.S. Navy victory at Midway was put in place
long before Japan’s four aircraft carriers were actually engaged in battle.
Sailors fighting north of Midway seventy years ago could not have imagined today’s high-tech
U.S. Navy with its long-range platforms, sensors and systems. Navy PBY-5A flying boat crews
using binoculars to locate enemy warships at sea have given way to manned and unmanned
aircraft and sensors, underwater surveillance vehicles, and reconnaissance satellites exploiting
virtually every segment of the electromagnetic spectrum. Navy code breakers and intelligence
analysts have replaced their mechanical machines and card files with sophisticated high-speed
computers able to access literally petabytes of data on enemy capabilities, movements and
intent. Navy orders once relayed by flashing light, semaphore flags and Morse code now travel
via secure data links and worldwide networks, connected by high-bandwidth satellites and
linked to the cyberspace in which we all now live. Taken together, a Navy commander’s basic
insight into what was actually occurring on, below, and above the high seas off Midway in
1942 has morphed into the unprecedented level of battlespace awareness we enjoy today.
While much has changed since Midway, the fighting spirit, the will and the dedication of
Navy’s information experts endure. As part of the newly integrated Information Dominance
Corps, today’s Navy information experts working together in the fields of intelligence,
cryptology, electronic warfare, command and control, space, cyberspace and oceanography
are quietly paving the way for success in future battles within the complex, information-rich
operating environment of the 21st Century.
4
Robert Huddleston is a retired Navy Captain currently supporting the Deputy Chief of Naval Operations for
Information Dominance (N2/N6).
Information Dominance Corps Newsletter / May 2012