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NO. 609
CCH-E32-93-04
i/1
~ II
TOP gECRET
PIJRPLE D R A G O ~ :The
Origin and Development
of
theUnited States OPSEC Program
united states cryptologic history
I HIS DOCQlvlENI CON IAiN5 C O " ~ V V O ~ O r v l t f f E ~ I A Lr ~ e T ~ E L E A ~ A I ; L E TO f i e ~ E I C ! l r ~ r ~ t ( T I O r ~ A L 5
Classified by: NSAlCSSM 123-2
Declassify On: Originat ing Agency's Determinat ion Required
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This monograph is a product of th e National Security Agency historyprogram. Its contents an d conclusions ar e those of t he au th o r, b ased onoriginal research, and do no t necessarily represent th e official views ofth e National Security Agency. Please ad dr ess d iv erg ent opinion or
additional detail to the Ce n te r f or CryptoJogic History (E324).
Contents of this publication should not be reproduced or further disseminated outside th e U.S. Intelligence
Community without the permission of th e Director, NSA. Inquiries about reproduction an d dissemination
should be directed to th e Center for Cryptologic History, National Security Agency, Fort George G. Meade,
MD 20755-6000, ATTN: E324.
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"
lOP SECRET tJM8ftA
UNITED STATES CRYPTOLOGICHISTORY
Series VI
The NSA Period
Volume 2
PURPLE DRAGON:
The Origin and Development ofthe United States OPSEC Program
(b ) ( 3 ) -P .L . 86-36
CENTER FOR CRYPTOLOGIC HISTORY
NATIONAL SECURITY AGENCY
1993
NOT REIoEltSABIoE TO FOREIGN Hft'i'IO?L',LS
iUP SECRE i UMBRA
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rep SECRET l:JMBRA
Table of Contents
Page
Foreword v
Acknowledgment Vll
Southeast Asia Map ix
Part I: Introduction 1
Part II: The Beginnings OfOPSEC 7
Part III: PC"RPLE DRAGON atWar 35
Part IV: NSA and PC"RPLE DRAGON 57
Part V: What Charlie Knew . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Part VI: OPSEC Goes Worldwide .
Part VII: PURPLE DRAGON at Peace .
. 75
. 89
Author's Biography 94
Abbreviations and Covernames.. 95
Bibliography 99
~ T Q T RIH,l!1ASASbl!1 'Y'8 F 8 R l ! J f 6 r ~ U A ' f I O ! G A L ~
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Foreword
TOP 5!Cft!T tJM!RA
(b ) ( 3 ) -P
86-36
Operations Security (OPSEC) as a concept is probably as-old as/war $tself.
Nevertheless, the fact that poor OPSEC practices have/been costly in loss of
human life and l os t obj ec ti ve s in every American war demonstrates. that,despite its venerated age , Ope ra ti ons Security/as a doctrine needs Fto be
learned afresh by each generation.
I t is imperative that thos e w ith r espons ib ili ty for.: military activi t ies
understand that observat ion of Operat ions Secur ity principles is as essential an
ingredient to victory as any of theother tools of war.vTo the extent possible,
these lessons should be learned in peacetime -- experience in recent conflicts
shows there is unlikely JO be a period of grace once a military emergency
occurs and troops are committed to combat.
I lin PURPLE DRAGON: The Origin and Deveiopmeii: of theUnited States OPSEC Program has given US a superb monograph about the
genesis of Operat ions Securi ty during the Vietnam War.llthoroughand re ad ab le accoun t describes th e in itial problems in air operattons which
prompted a high-level investigation, explains the weaknesses in U.S. practices
which this investigation identified, shows how Operations Security principles
were developed through c lo se analys is o f the problems and weaknesses, and ,
finally, tells how Operat ions Secur ity at l as t became ins ti tu ti onal iz ed . Of
primary importancej Ishows clearly that complacency is dangerous,
not only before th e principles of Operations Security have been applied, but
even after , as situations evolve, personnel change, and the adversary
undertakes new intelligence initiatives.
The Center for Cryptologic History believes t h a ~ Fonograph is
an important addition to the study of cryptologic nIstory and, mdeed, to the
l i terature on the Vietnam War. I t has much to sa y to two audiences: those
unfamil ia r with Ope ra ti ons Secur it y will find it a good introduction to the
concepts and methodology of this important component. Those already
fami liar wi th Operations Security should f ind it an in te res ting study of OPSEC
origins as well as a refresher on th e basic princ ip les o f the discipline.
This story of PURPLE DRAGON is not just for the military; its lessons
apply to the civilian cryptologic professional as well. The Center for
Cryptologic History hopes that this study will reinforce the impor tance of the
doctrine and help us to examine ou r premises and practices, military and
civilian alike.
DAVID A.
HATCHDirector,
Center for Cryptologic History
I . e , f t r : L ~ A ~ A ! 5 L ! ! ; TOFOREIGN NAtiONALS
v 'FBP Sf€ftff tJMBRA
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TOP SECRE I UMBRA
(b ) ( 3 ) -P .L . 86-3
Acknowledgments
(U) I wish to take th i s oppo rtrun i ty./ to thank \.evetyone
who con tr ibu ted to the product ion of th i s monograph.
F i r s t , I would l ike to thank a l l those / who q r ac i ou s-Ly
consented to speak wi t h me concerning t he i r e x p e r iences
with PURPLE DRAGON and OPSEC, especiallyl. IL...- .".....---.,,...-.,,..,.._---...Iandl . Ii The ira s s i s t ance
was t r u ly indispensable . I Mould also l ike to express my
gra t i tude to the employees of th e NSA archives .
(U) I would also 1 ike to thank those who read the
dra f t of th i s paper , reviewing it fo r factuaV content and
s t y l i s t i c reasons . Among those who provided va luable
sugges t ions , I pa r t i cu l a r ly wish to thank Milton Zaslow,
__________Iand NSA's Office of Operat ions Secur i ty .
(U) Spec ia l thanks must go to David Hatch and Hen' r y
Schorreck, the cur ren t and former His tor ians of th e
Nat iona l Secur i ty Agency, and th e other members of t he
Center fo r Cryp to log ic His tory fo r g iv ing me the
o pp or tu nity to produce th i s paper and fo r pu t t ing up with
me whi le I worked on it.I I
my ed i to r a t
the Center , deserves spec ia l thanks fo r her e f fo r t s in
making the f in ished product presen tab le .
(U) Fina l ly , spec ia l thanks t .ol---------- . . . . . ,withou t whom I never would have/undertaken th i s pro j e c t .
(b ) (6 )
July 1993
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Part I
Introduction
WHYOPSEC?
CD) Throughout the history of armed conflict, a few general tactical rules have directed
the actions of armies around the world: control the high ground; preserve your supply
lines; and, most of all, maintain the element of surprise.
CD) Generals have always recognized that tactical surprise is one of the most effective
force multipliers available to them. Because of this, one of the primary objectives of every
military campaign is to strike when and where the enemy least expects it and before he
can take defensive measures. As the Chinese general Sun Tzu, writing in the fifth century
S.C.E., advised, "Take advantage of the enemy's unpreparedness; travel by unexpected
routes and strike him where he has taken no precautions." Another Chinese general, TuMu, said of Sun Tzu's advice, "This summarizes the essential nature of war ... and the
ultimate of generalship." 1
CD) In the twenty-five centuries since Sun Tzu, military history has been reple te with
examples of battles that were won in large part because an at tacking army was able to
maintain the element of tactical surprise. One battle, the first battle of Trenton during the
American Revolution, can stand as a classic example of the benefits of tactical surprise.
CD) Following a successful campaign in New York and New Jersey dur ing the summer
and fall of 1776, the commander of British forces in North America, Si r William Howe,
decided in early December to suspend operations for the winter. British troops and their
Hessian mercenaries were therefore bivouacked in a series of outposts acrossI \
ew Jersey.Bivouacked in Trenton were three Hessian regiments, plus miscellaneous troops and
artillery under the command of Colonel Johann Rall - in all, about 1,400 men. Although
instructed to build defenses for his t roops, Rall, convinced that the Continental Army
posed no threat to his position, merely established sentry posts throughout the town.
CD) On Christmas night 1776, while Rall and h is men celebrated with extra rations of
rum, General George Washington set in motion one of the great surprise a t tacks in
mili tary annals. After ferrying across th e Delaware River , which the British and
Hessians deemed impassable due to floe ice, the Continental Army marched all night
through the snow and, by dawn, 26 December, had managed to surround RaIl's troops on
three sides. Surprise was so complete that the f irst evidence the Hessians had that the
Continental Army was even on the move came when a sentry on the nor th side of Trenton
caught a glimpse of the main Continental force on the edge of town. Before he could raise
the alarm, the Continentals attacked. In the forty-five-minute battle that followed, RaIl
was killed while trying to rally his disorganized and unprepa red t roops, and the
rw'f R E L E A : S A : ~ L E TO P"OItJl::IGN NAtIONALS
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Continental Army captured more than 900 prisoners, as well as large stores of arms,
ammunition, and provisions. American losses were negligible. 2
(U) While history shows many instances of battles like Trenton, won because an
attacking armymaintained the element of surprise, it is equally full of examples of battIes
lost by the failure to maintain surprise. An example of this, also from the American
Revolution, was the British march on Lexington and Concord on 19 April 1775.
(U) Based on intelligence that the Massachusetts Provincial Congress was gathering
military stores in the town of Concord, the royal governor, General Thomas Gage, decided
to send a troop of approximately 700 light infantry and grenadiers to Concord to destroy
them. Gage's actions, however, soon gave his plan away.
(U) Beginning on 14 April, Gage relieved the grenadiers and light infantry from their
regular duties, ostensibly for training in new drill and maneuvers. Furthermore, on 15
April all of the long boats and barges of the Bri ti sh t ransports in Boston harbor were
transferred to shore.
(U) These events did not go unnoticed by the populace of Boston. On 15 April, Joseph
Warren, the pat riot l eader in the city, dispatched Paul Revere to Lexington to notify
Samuel Adams and John Hancock of the developments . Word of the British actions also
spread to Concord, where townspeople began removing the military stores to Worcester,
further inland. On his return to Boston, Revere also met with Colonel William Conant of
the Massachusetts militia in Charlestown and agreed to establish a signal in Boston's Old
North Church which would indicate when the Brit ish troops began to move and whether
they were crossing to the mainland by way of Boston Neck or crossing directly over the
Charles River.
(U) The situation in Boston remained tense bu t quiet for the next two days, bu t on 18
April the HMS Somerset, without warning, was moved from its moorage in Boston harbor
to a position at the mouth of the Charles River, where it would be able to control the ferry
between Boston and Charlestown. General Gage also dispatched small squadrons of troops
in the late afternoon to patrol the roads between Boston and Concord and prevent any
messengers from getting through, and he ordered the sentries at Boston Neck to challenge
anyone trying to leave the city. Finally, in the. early evening, the l ight infantry and the
grenadiers began to quietly assemble at the foot of Boston Common, on the banks of the
Charles. By eleven o'clock, the first troops had begun to embark for Charlestown.
(U) The implications were clear. Warren dispatched Revere and William Dawes to
ride to Lexington and notify Adams and Hancock to escape, in case their capture was the
object of the British troops. Revere and Dawes were also to rally the local militias andhave them muster at Concord, in case the military stores were the British objective.
Before setting out, however, Revere had two lanterns hung in the Old North Church's
TOP§&CAET I:IMBAA
NO'!' RELEASABLE i 0 POft!I6r,,- UAo'fI8NAhS
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..
Tap SEERET tJMBIb\
spire to notify the milit ias on the northern and western banks of the Charles that the
British were coming.
(U) The two riders then se t out. Revere lef t Boston by rowing across' the Charles right
under the guns of the Somerset, apparently without being detected. Dawes, meanwhile,
somehow managed to convince the sentry on duty at Boston Neck to le t him pass. Anyway,they both managed to get out of Boston and, as the famous poem relates it , to spread the
word to everyMiddlesex village and farm.
(U) By the time the British troops arrived in Lexington on the morning of 19 April,
they did not find Adams and Hancock. They did find a small body ofmilitia on Lexington
Green. A quick skirmish put the milit iamen to rout, and the British were soon on the
march again to Concord.
(U) At Concord the British found and destroyed most of the mili tary stores still in the
town. They also found a larger body of local militia, with more coming all the time. The
British confronted, and were defeated by, the militia at Concord's North Bridge. Sensing
that the situation was, or soon would be, desperate, the British began the long retreat backto Boston. The retreating column came under constant harassment from the militiamen,
suffering heavy losses, and only the arrival of 1,200 reinforcements from Boston saved the
original column from destruction. The Brit ish troops faced heavy fire all the way back to
the Charles River, where the guns of the fleet in Boston harbor finally convinced the
militiamen to cease their attack.
(U) The Brit ish would remain besieged in Boston until the followingMarch." The first
day of the American Revolution thus ended in a stunning upset as one of the most
professional a rmies in the world , wel l armed and well trained, was routed by a
disorganized rabble of farmers and tradesmen, most of whom had never fired a shot in
anger before in their lives. And all because the Brit ish could not keep their intentions a
secret.
(U) As Washington himself wrote in 1777, "upon secrecy, success depends in most
enterprises . . . , and for want of it , they are generally defeated, however well planned and
promising a favorable issue." 4 From the Revolution to the present, the United States ha s
made a concerted effort, through such means as physical security, cryptography, and
counterintelligence, to keep information concerning its intentions and capabilities from
falling into the hands of it s enemies during wartime.
VIETNAMASAN OPSEC CATALYST
(U) Bu t while the benefits of maintaining the e lement o f surprise as a military
objective, and the dangers of losing that surprise, have always existed and have been
recognized as vital to tactical, and even strategic, success, it was only dur ing the war in
NO1RELEASABLI!: TOf'Ofti'lf8N ' N'A'fI9l'TlzeS
3 T8P SECRET l:lMIlRA
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,er !!!e;"I!!' tJFI,n"A
Vietnam that the United States began to make a concerted effort to review it s security
posture from the vantage point of an adversary in order to identify that information
concerning U.S. intentions and capabilities that an adversary considers vital, to discover
how he gains such knowledge about U.S. military plans and capabilities, and, finally, to
develop strategies by which U.S. commanders could prevent h im from gaining that
knowledge. This "ability to keep knowledge of our s trengths and weaknesses away from
hostile forces'" became known as operations security, or OPSEC, and had its birth in an
operation known as PURPLE DRAGON.
(U) Early in its involvement in Vietnam, the U.S. military came to the realization that
several of i ts operations were not being fully successful. Enemy forces were somehow
consistently able to avoid the worst consequences of U.S. and Allied operations, and senior
U.S. commanders wanted to know why. Assuming that North Vietnam and the Viet Cong
were not l ikely to be decrypting the United States' most secure communications and that
they could not have enough spies in South Vietnam to be aware of every U.S. operation in
Southeast Asia before they took place, U.S. personnel came to the conclusion that U.S.
forces were themselves inadvertently revealing vital information to the enemy.
(L'") To test this hypothesis, the U.S. Joint Chiefs of Staff authorized Operation Pl:RPLE
DRAGON. Relying on a multidisciplinary investigation of al l aspects of combat operations,
from conception to planning to execution, the men of PURPLE DRAGON sought to uncover
those elements of an operation which might be insecure and which of those elements might
be able to provide valuable, exploitable information to the enemy. Once uncovered,
PURPLE DRAGON could then suggest possible remedies for those elements to the concerned
commanders in the field.
(C) From it s inception in 1966 and 1967, PURPLE DRAGON proved a major success at
improving the combat effectiveness of t he uni ts and operations it surveyed. PURPLE
DRAGON was so successful , in fact, that before the war was over the Joint Staff madeoperations security programs, based on the PURPLE DRAGON model, mandatory for al l U.S.
commands everywhere in the world. Operations security would prove so successful in the
end that President Ronald Reagan would make it a requirement for every U.S.
government department or agency, military and civilian, with a national security mission.
(U) It is the goal of this study to explore why and how operations security in general
and PURPLE DRAGON in particular came about. It will attempt, furthermore, to show how
the concept and methodology of OPSEC were developed; how OPSEC came to prove itself in
the rice paddies and jungles of Vietnam; how it came to win acceptance, f irst among the
U.S. military in Southeast Asia and the U.S. Pacific Command, then by the U.S. military
establishment worldwide; and, at last, how operations security came to become an official
policy of the Uni ted States government. Final ly, it will seek to document the vital role
that the National Security Agency has played in the development of operations security,
from the birth ofOPSEC during the conflict in Vietnam to the present day.
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TOPSECRET l-:IMBRA
Notes
1. (U) Sun Tzu. The Art ofWar. Trans. Samuel B.Griffith. (London: Oxford University Press 1963),134.
2. (U) Bruce Lancaster. The American Revolution. (New York: The American Heritage Library, 19711, 161-166;
Willard M.Wallace. Appeal to Arms: A Militory History of the American Revolution. (Chicago: Quadrangle Books,
1951), 127-131.
3. (U ) Lancaster. 84-91;Wallace, 12-26.
4. (U) George Washington, letter to Col. Elias Dayton, 26 July 1777 ,quoted in Jack Ingram, "Historical Impact of
OPSEC onMilitary Operations" (NSA Video) (FOtJO>.
5. (U) William O. Studeman. "Cryptologic Orientation Welcome Address" (National Security Agency Video TVC
1984,1989) rsi
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Part II
The Beginnings ofOPSEC
WHY PURPLE DRAGON?
CU) On 7 February 1965, a Viet Cong CVC) platoon attacked the U.S. air base at Pleiku,
about 200 miles north of Saigon, in the Republic of Vietnam CRVN or South Vietnam).
During the attack, the VC destroyed one transport aircraft and nine helicopters and
damaged fif teen other aircraft. They a lso b lew up a barracks, killing eight U.S.
servicemen while wounding 126 more.
CU) In response to the Pleiku attack, President Lyndon Johnson approved a proposal
for continuing ai r s tr ikes against targets in the Democratic Republic of Vietnam (DRV or
North Vietnam), as opposed to the policy of quid pro quo retaliations for North Vietnamese
attacks that had been in effect since the Tonkin Gulf incident of August 1964. The first
raid under the new policy took p lace on 11 February 1965, when 160 U.S. and RVN Air
Force and Navy fighter-bombers struck targets north of the 17th parallel, the official
boundary between the two countries. The policy of continuing ai r strikes north of the 17th
parallel, to be carried ou t by fighter-bomber aircraft, was given the covername Operation
ROLLING THl:NDER. 1
(U) On 17 June 1965, U.S. B-52 bombers from Andersen Air Force Base in Guam for
the f ir st t ime launched a mission against a VC stronghold in South Vietnam. Thi s and
future B-52 missions from bases in Guam, Okinawa, and Thailand were covernamed
Operation ARC LIGHT.2 From that time on, ARC LIGHT s tr ikes aga inst VC and North
Vietnamese Army (NVA) targets in South Vietnam and ROLLING THUNDER strikes against
targets in North Vietnam became an almost daily occurrence.CU) By the summer of 1966, however, it had become clear that the bombing missions
were not having as significant an effect on the VCINVA as had been expected. Ground
sweeps and bomb damage assessments of B-52 target areas discovered lighter enemy
losses, in both men and mater ia l, than expected, and North Vietnamese infiltration of
more men and material into South Vietnam was apparently not being inhibited by air
strikes in the DRV. Morale in the VCINVA still seemed high after a year of bombing, and
North Vietnamese military and industrial activity did not seem to have been severely
hampered." The concern was on many people's minds - was U.S. intelligence concerning
the enemy's whereabouts and strength faulty or, more ominously, were the the ARC LIGHT
and ROLLING THUNDER missions being given away in advance, providing the VC/NVA the
opportunity to avoid them?
( g W ¥ ) ' ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 1DIA
7
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~ 0 .. _ •
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Admiral U.S. Grant Sharp, USN
Commander in Chief, U.S. Pacif ic Command
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President Lyndon B. Johnson and
General Earle Wheeler, USAF, Chairman of th e Joint Chiefs of Staff
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The final proofof the meaningIr-----,.....-"""":"'""""":"'"--:---=-:-:::"""":'----:-:---........---:---:-!......
---'came during the U.S. bombing moratorium between 24 December 1965 and3.1 January 1966. The messages.stopped along withthe......•b.ombing. Ry early 1966, theanalysts at NSA were able to sho1 ... ..... Ito between 80 and
90 percent of al l ROLLING THUNDER missions. to
~ A f t e r performingmore analysis of the l inks betweeni land ROLLING
THUNDER durin the earl part of 1966, 821 finally released a re ar t of it s findin sin Ma
detailin The effect was immediate.
821, had uncovered evidence of Chinese forces in~ ' : " " " " ~ - : - : : - : - - " " ' " " ' " ~ " " " : " ' : = ~ ~ ~ - - - : ~ - - - : , ~North V i e t n a n i ( C F ~ V N ) and had begun full-time monitoring of manual/morse code
communications between
I land the CFNVN. Fo rseveral months these communications consisted of short, formulaic messa es
""\rSCl..Play'ing a hunch byE. Leigh Sawyer, t hen chief of B21, analysts began
comparing thel I m e s s ~ g : e . s against.U.S. operations in Southeast Asia. They
discovered an apparent match between the(/ Imessages and some ROLLING
.......U o . l o . : ~ . w . I O o , I A . . ~ · s s i o n s . Upon further analysis,Jhey discovered a near perfect match between
nd lanned ROLLING THUNDE.Rmissionsover the northeast uadrant of Korth
;.....
B21 also produced another four reports on' r - - . . . . . , . . - - - - ~ _ : _ - " " " " : " ' " " " " " : " " ' : - - - ~ 1....-__ .....
messages, their probable content, and their relationship to ROLLING THUNDER"----:---:-'
missions, during the course of the next three months. Leigh Sawyer gave a private
briefing onl Ito General EarleWheeler, chairman ofthe JCS. After the briefing,
I , e J T f t E L } ! ; A ~ A I 5 L t IOFOREIGN NAtIONALS
Tel' !!(:RET tJI'OiBRA 10
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)
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) -1 8 USC 79 8
) -P .L .
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according to Sawyer, Wheeler's only response was to slam his fis t on the desk and shout,
"Goddam it, we've been penetrated!" 11
('fOC UP) :At the same t ime as it s findings onl INSA was' uncovering other
evidence of hostile prior knowledge of U.S. air operations in Southeast Asia. The Strategic
Air Command (SAC) had begun overflights of North Vietnamese and Chinese territories
using low altitude photographic reconnaissance drones in 1964, covernamed BLUE SPRINGS
in 1966 and redesignated at various times BUMBLE BUG, BUMPY ACTION, and BUFFALO
HUNTER. C-130 mother ships operating out of Bien Hoa ai r base in South Vietnam would
release the drones over Laos or the Gulf of Tonkin; the drones would overfly northern
North Vietnam and then b r cov r d over the Gulf b helico ters 0 eratin out of D
Nan ,
"'PGG)..L'iSA had a l s 6 u n c o v e r e d e Y i d e n c e u o f ~ o r t h Vietnamese alertin of ARC LIGHT
missions dating back at least to late 1965. These alerts,
were issued on 34 percent of B-52 strikes during 1966, with an....._----.....,.-""':"""".....
average warning time of eight and a half hours. Though usually general in nature, theVietnamese alerts did occasionally include detailed targeting information.13
l ' I5C ? ~ ) I
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·,;. /
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Lt . GeneralMarshall S. Carter, USA
Director, National Security Agency
I
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(U) The problem with monitoring, however, was that COMSEC monitoring, by it s very
nature, was selective, the findings being limited by the fact that the SeAs cou ld not
monitor all communications all the time. Monitoring, furthermore, could uncover COMSEC
lapses only after they had occurred. 19
b) ( 3 ) -P .L . 86-36
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(b ) ( 3 ) -P .L . 86-36
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BIRTH OF THE DRAGON
-tTSfAt the beginning of the PURPLE DRAGON survey in December 1966, the surveyteams lacked clear guidance on what they were looking for and how to proceed. However,
following a briefing from CINCPAC on the sort of information they were to seek, and
improvising as they went along, the PURPLE DRAGON teams and staff were able to develop
an efficient method for both the gathering and the analysis of information on potential
sources ofenemy foreknowledge and forewarning. The PURPLE DRAGON teams decided that
the fundamental process of the surveys would be to "put ourselves in the position of the
adversary and s tudy our operations step by s tep, from concept ion through execution to
completion and beyond." Furthermore, they would focus their attention on the small,
seemingly insignificant details of the surveyed operation, considering them to be just as
likely, i f not more so, to provide valuable information to the enemy as the major aspects of
the operation."
kSrThe PURPLE DRAGON survey teams' f irst order of business was to develop a complete
overview of the operat ion and of each mission in that operation. Though already
knowledgeable about the operations they were to survey, the teams began by reviewing
"operations o rder s and directives, communications-electronics operating instructions,
pertinent COMSEC .. .and such other documentation" so that they would be as familiar as
possible with "the details and possible weaknesses of the operation before
commencing. . . . " 35
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b) ( 3 ) -P .L . 86-36
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U.S. Ai r Force CH·53 helicopter recovering a
BLUE SPRINGS reconnaissance drone over the Gulf ofTonkin
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i r Combat
~ N'l'J On being apprised of PURPLE DRAGON's findings c ~ n c e r ~ i n ~ L . : - ~ ~ _ - - - - J11 I fSAC began to upgrade it s worldwide operations
codes, ByTJUije1967, land, by the
following spring, two I I had been
introduced. Also as a result of PURPLE DRAGON, CINCPAC ordered the installation of aKW-26 secure teletype link between Bien Hoa and Da Nang to handle BLUE SPRINGS
t raff ic. In fact, the KW-26 was on-line between Bien Hoa and Da Nang within a week after
CINCPAC's J-6 was apprised of the situation. The KW-26 l ink was s ti ll later replaced by
an HY-2/KG-13 secure voice link between the two bases. 50
"'t;:,-mqj
ARC LIGHT MISSIOXS
(U) On ARC LIGHT missions, PURPLE DRAGON found several l ikely sources of enemy
foreknowledge and forewarning. Under International Civil Aviation Organization
agreements, every t ime an aircraft is scheduled to pass from the control of one air traffic
control (ATC) center to another, it is required to file a flight plan with its local ATC center
and to notify t he new ATC center of its expected arrival t ime and location in that center's
zone of control and request an altitude reservation (ALTREV) for its flight path through
that zone. The new ATC center will then publish a Notice to Airmen ( N O T A ~ l ) , giving
flight particulars such as altitude, flight path, and entry and exit t imes and locations from
the ATC zone, which it broadcasts to al l adjacent ATCs so they will be aware of th e
aircraft's presence.
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) ( 3 ) -P . L . 8lep SECRE'f t:JMBR;6;
( ' f ~ C ) Following the implementation of PURPLE DRAGON'S recommendations on ARC
LIGHT, enemy alerting of 8-52 strikes dropped significantly, at least by the two broadcast
stations identified by NSA. During December 1966, the f irst month of the PURPLE DRAGON
survey, the two NVA s ta tions had alerted 34 percent of ARC LIGHT missions with an
average warning time of e ight and a half hours. In April 1967, a t th e end of PURPLE
DRAGON, NVA alert broadcasts had fallen to only five percent of B ~ 5 2 s tr ikes , with an
average alert time of less than thirty minutes.P' (b ) (1 )
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l:.S. Air Force F-105 fighter bombers en route to North Vietnam on a ROLLING THC'.'i"DER mission
U.S. Navy A-4 f ighter bombers on a ROLUNG THUNDER mission
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26
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(U) Because of the radar surveillance problem, PURPLE DRAGON decided to make no
major recommendations, beyond those already mentioned, for eliminating possible sourcesof enemy foreknowledge and forewarning of ROLLING THUNDER missions. Consideration
was given to recommending changes in refueling aircraft communications procedures, bu t
it was decided that the changes would only needlessly complicate refueling operations
without significantly lessening the enemy's warning time.68
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(b ) ( 3 ) -P .L . 86-36
1. (U) John S. Bowman, General Editor. TheW-OrldAlmanac of the Vietnam War. (New York: World Almanac,
1985), 104-105;1 IrheGreat Conversation: TIu! Origins and Development of the National
Operations Security Program. (Interagency OPSEC Support Staff, 1991),2,
2. (U) Bowman, 118.
3. (U) Walter G. Deeley. "A Fresh Look at Purple Dragon." SIGNAL, Volume 38, Number 8, Apri11984, 18.
4. Donzel E. Betts, et al. Deadly Transmissions: COMSEC Monitoring and Analysis. (National Security
Agency, CryptologicHistory Series, December 1970), 87 (S NF).
5 . ~ B e t t s , e t a l . , 89-90 (SNF).
. '
~ f O l ' R 8 ~ E A S A B L f J 'f 6 F6RfJI6H IofJ\TI6N'J\L8
31 TOP SECftH t1M8l\A
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( b) ( 1)
(b ) (3) -50 USC
403
( b) ( 3) -P .L .
86-36
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) ' (b ) (1 )
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6 . lftHistory of a Dragon." DRAGON SEEDS, Volume 2 N ~ ber III, September 1973,29 (TSC).
National SecurIty Agency, Memorandum for the Chief, ADSpJ JSubject: OPSEC Support. 16 June
1971 (TS NF LIMDlS CeO).
7. (U ) Central Intelligence Agency Intelligence/Memoranduml j r h e E f f ~ ~ t i v e n e s s of theROLLING THUNDERProgram in North Vietnam: 1 January-30 September 1966. November 1966,7-8 8 (TSC) E.
Leigh Sawyer. "Pursuit of thelt
CRYPTOLOG, Volume IV, Number 3, March 1979, 1 (TSC).I ~ e l e p h o n e l n t e r v i e w with the Author. 2 March 1992.
8. Sawyer, 1-2(TSC)
9. ~ I b i d . (TSC).
10 Af8CT Ibid ·1 I j n ~ e r y j e w .
1 1 ~ ) Sawyer, 4-5 (TSC)c:=Jnterview(TSC).
12. \TS€f Peeley,18; Donzell E. Betts, et. al.
Working Against the Tide (COMSEC Monitoring an d Analysis). (National Security Agency Cryptologic History
Series,June 1970),131.
13.1'TS6iI I-Director, NSA (DIRNSA) Memorandum toNSA;Rllpresentative,
Pacific Command (NSAPACl. 9 August 1966. <S-CCO); NSAPAGMemorandum to DIRNSA. "VeWarning of
ARC LIGHT Strikes." 29 September 196&(SC):
14. -«'fse lGl"I Sawyer, 4-5 aSC); 1-----......--------11 ~ ! 9 ( T S C J ; Betts. Deadly
Transmissions, 91 (SNFI.
15. NSA InterviewJ 12& February 1 ~ 9 2 , bj . IOH.10.92'Se l l t e r fo f
Cryptologic History ( S . C ~ O l ; Dee ley.T?'; NSAlnterview, David G. Boak, 5 MarchJ992, b ~ I - " , , " " , , ; " " ......__..... .----'and CharlesW. Baker. OH.12-92. Center for CryptologtcHistory (S-CCOl.
:: : f l : : ' ~ : . ' . V . ' . i . ~ : ~ = l l : : : : ~ ~ ~ ~ : ; : : : ~ ~ ; l } ~ ~ . ..•.;~ . H1. 92fS CCOI; 0.;•I.:.e\i: .. .
17lSI
1 8 . ;U i n t e r v i ew . OH-10-92 (S-CCO); Deeley, 17(U). ". ". .//'
19. (U ) Deeley,17 (S) . ;. ". ". .: .-
interview. O H ~ 1 0 - 9 2 ; Deeley, 1 7 - 1 ~ ; B o a k Interview. OH-12-92 (S-CCo>,
interview, OH-10c92 (S-CCQ); Deeley, 17-18; Boak interview. OH-12-92.rS·CCOl.
interview.OH-10-g2($·CCOl; Dee l e y , 18 (S l . \ /
r-"";; ';; ';" '=I-_. . .i;;;;.n;.;.te.,rvieJl,0H-10-92 (S-CCOl; Deeley, 18; BoakirtfepJiew. OH-l2-92 (S-ccol.....__ ...... _
Betts. Deadly Transmissions, 91 (S NF). .1.. . - ..1
2 4 . ~ Ibid., 91 (SNFl.
2 5 . ~ I b i d .
... . / /\\
Belts,DeadlyTransmissions,9"l\S NF).
30. Qterview.OHclO.,g2tS-CCOl; Deeley, 18.
31. " T l ~ ~ ~ L " " ' ' ' ' ' ' ' ' ' " " " " , ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' " " ' T " " " " , . " . , . " . " , . . . , . . " " " " " , = ....., J 6 : = ~ J ; . t e r v i e w . OH,10cg2 (S:OCO); Betts. DeadlyTransmissions. SeN-F) .. . . . . .
( b) (3
OGA
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(b ) ( 3 ) -P .L . 86-36
TOP S E E R ~ f tJMBRA
NOT RE I E ASA pI i '"{:Q ¥'QRBION H * ' f [ ~ I 4 ' A L 5
32
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Tep 51!CRE i UMBRA
(S) Boak
/ i ( b ) ( 3 ) -P .L . 86-3
51:
52;
53..
54.
55: (TSE]
5 6 . \ ~ F - - - - - - - " " " " " " 1 (S NF) Betts. DeadlyTransmissions,94 (S NF).
57. Ibid.,.94 (S NF).
sa, ' ¢ )c : J (n te rv iew. OH-I0-92 (S-CC(». .
5 9 . ~ I Betts. Deadly Transmissions, 94 (S NFl ; Deeley, 18 (SCl.
6 0 . ~ D I A TS-SI-60IPL. figure 1.(TSq NFl; ibid. , 11. (TSC NF).
::=t _
32. Ic = J n t e r v i e w · Q t I ~ 1 0 - 9 2 ( S - C C O ) ; Betts. Deadly Transmissions,92 (S NF) . / ' - - . . . . l
33. ID r n t e r v i e w : o H ; T O ; 9 Z ( S ~ C C b ) .3 4 . ~ JI fhe G r e a t ~ ~ ~ v e T s a t i 6 n , 5 ( S ) ;~ ~ t ~ ) 1 ~ ~ ~ ~ ~ n d e r . i n . C h i e f , Pacific, [ n s t r u c t i O n ( ~ I ~ ~ ~ A C I N S T ) 0 0 3 1 0 0 . ~ . O p e m t w a S $ e c u r i t y(OPSEC). 26iHi: ¢)CINCPAC SSO Serial 00026-71.0verationsSecurity (OPSECYReport. 1 JUQe>19'7173-74 (TSC)
37.P) CINCPACINST003100.54 (S); CIJ'(CPAC S S 0 9 0 0 2 6 ~ 7 1 , 7 3 - 7 4 , 76 (TSC).38 .ADi r t f e I " \ ' i ew .OH-I0-92 (S-CCOl.
39 . .¢)CINCPACINST003100.5,1 (S)
40. Jt) Ibid. , 1 (S); CINCPA.CSSb()O.?26.·,11,77 (TSC); .•I'-- '--_,;.....Itnterviewwith the author. 12February 1992\S).
41. ~ CINCPACIl'[ST003 100,5,1-2, 5-6.
4 2 . ~ D i l 1 t e r v i e v , ' , O h ~ 1 0 - 9 2 (S ccoa CINCPACINST 003100.5, 6-7/\8l.
4 3 . ~ n t e r v i e w . OH-I0-92 (8-CCO). (Ui· / / ~ 6 MayJ993 memorandum td - - - ,
I I(U) Joint Chiefs of Staffpublication 3.54. Joint Doctrine for Operations Security, 22 August 1991.
44. ~ C I N C P A C SSO 00026-71, 77 (TSC).
45. ,¢)CINCPAC SSO 00026-71, 74, 77 rrsc» Din t e r v i ew . OH-I0-92 ($-CCOl.
4 9 _ ~ I47. interview. OH-1O-92 .sccoir tnterview (S-CCO);
e au t or. 4 February 1992, / (S NFc:::::readly Transmissions, 92 (S NFl;
Dee ey, 18(_T...;..;;-.;... ___
4 8 . ~ I<S...;;C..;;C..;;iO;';)L,..._-Jinterview. OH-I0-92 (S.CCO)I Interview
( ~ : C C O l ; Boak interview. OH-12-92 (S-CCO); nterview. B'etts,DeadlY Transmissions, 93 (S NF).
49. ~ c : : : : : I n t e r v i e w .5 0 : ~ ) B e t t s ' / D f f l d l ' y ' T r p . . o . ~ ~ I i l l l ~ ~ . J . > 2 . . . I : : U : l . . . . . . . . L ~ .......---1interview. OH-IO-92 (S-CCO)
interview. OH-12-92(S'CCO);
DIA
(b ) ( 3 ) -P .L . 86-36
33 TOP SECRET UMBR>\
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l'6J1 seCRET tlMBR-A
Part III
PURPLE DRAGON at War
COMMANDER IN CHIEF PACIFIC
CINCPAC PURPLE DRAGON report coversheet ( a r t w o r k ~ ~ L . . . . - ---IIUSN)
P,ST R 8 L 8 A S l \ ~ L P ; f O P"REIGN NAIIONAtS
35(b) ( 3 ) -P .L . 86-36
TOPSEtRE' tJM8RA--
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TOP" 'RET l::IM8AA
OPSEC INACTION
I I
"--- .....,.,b) (1
CD) The teams also produced some fourteen OPSEC reports. Each PURPLE DRAGON 0
report consisted of the results of surveys conducted during the reporting period as well as
regular updates on the OPSEC status of Operations ARC LIGHT, BLUE SPRINGS, and ROLLING
THUNDER. Following the termination of ROLLING THUNDER in the spr ing of 1968, PURPLE
DRAGON began including regular updates on th e Strategic Air Command's SR-71 D
reconnaissance program over Vietnam and the Korean peninsula, Operation GIANT SCALE.
PURPLE DRAGON reports were unusual in that they did not go through the usual staffing
process at CINCPAC bu t were issued directly as written by the OPSEC branch. 1
CD) Following ar e a few of th e more significant operations security surveys conducted
during th e Vietnam conflict, which are representative of peRPLEDRAGON's usual activibes
and findings.
U.S. NAVYIMARINE CORPS AMPHIBIOUS OPERATIONS
TO.. 5eERET UMBRA 36
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'1=9P SECAE:rYMBRA
-
U.S. Marine amphibious landing, South Vietnam
NOT RKlsi: 'S/tHee 'f a Fetit6-l. NAtIONALS
(b) (1
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37 TOP 5I!!CR!f tlMBfbIc
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38
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C
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DIA
TO' SECRET b I ~ " S R A
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39
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)(1 )
A
...............
fefl 5!eR!'f UMBRA
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40
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"611 SECRET UMBRA
7IA
SOUTH VIETNAM
=
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Operation BOLD MARINER,Batangan peninsula and Mo Due, South Vietnam
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41 TOil SECRET blUBRA
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- ..
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..
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u.s. 9th Infantry soldier in the Mekong delta
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45 T9p SECRET l:IMBR,Ic
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T611SECRET l:JMBRA
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ff6'1' R ~ L ~ A : S A : B L ~ 'fe FeREH6NNA'fIONltbS
46
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-. ~ . ..TOP SECRET tJM8ftA
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47 iOPSECR!'f tJM8RA
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TOP SECRET U M ~ f t A
(b) (1)
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C.S. ground forces receiving tactical air support in South Vietnam
!\e'F I t E L E M ! 7 \ ~ L I ' : 'Fe FOltEI8li !41<'Fle!4l<L8
TOP SECRET U M ~ f t A 48
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.,.. '
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. 'FOP SEERE'F l:JM8RA
(C ) Following the PURPLE DRAGON surveys of Mobile Riverine operations and Army
ground operations, as with mos t PURPLE DRAGON surveys dur ing V ie tnam, t he OPSEC
posture of the surveyed organizations improved, at least temporarily. More important,
however, evidence of enemy prior awareness of the operations significantly decreased as
the surveyed units implemented suggested changes in procedures. U.S. intercept of enemy
alert messages dropped off, and contact with the enemy usually increased. These positive
results, however, were almost invariably only temporary. In most cases, the enemy, being
denied one valuable source of foreknowledge of U.S. intentions and capabilities by the
improved operations security ofthe units involved, would cast about unt il they had found a
new source of information to take its place. Then, evidence of the enemy's prior knowledge
would again surface and the OPSEC procedure would begin again.
ARC LIGHT OPERATIONSREVISITED
D
TOP SECR.H l:JMBAA 50
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TOP S ~ O l : E i UMBRA
(b ) (1)
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p.-" .... , ~ __:::.._-_._._..•.._,._ .•._...::,..
u.s. ground forces, fo reg round, watch th e resu l ts o f a B-52 strike in South Vietnam
dOT r t ~ L r : A ~ A r s L E Ie F c ! t ~ I e N NAtIONALS
DIA
51 I UP ~ ~ ( K ~ T UMBRA
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-.
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53
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Tap SECRET tJMBfM
Notes
(b ) ( 3 ) -P .L . 86-36
2.
TheGreat Conversation..4-5.r . - - - - - - ')Bowman, 428; CINCPAC SSO-00021-68, Operations SecurityReport. 1Apri11968, 18, 21 (TSC).
3. ~ I b i d . , 18 (TSC).
4. ~ I TS-SI-60IPL, 15 (TSC NF),
5. ~ C I N C P A C SSO-0002I-68, 18 (TSC).
6. ,Cll81Ibid.,18-19 (TSC); DIA TS-SI-60IPL, 15{TSCNF).
7. ~ C I N C P A C SSO-00021-68, 18-21 (TSC); orA TS-SI-60IPL, 15 (TSC NF).
8. CINCPAC SSO-00021-68, 18-19 (TSC); DIA TS-SI-60IPL, 15 (TSC NF).
9. ¢CINCPAC SSO-00021-68,19-21 (TSC).
10. Ibid., 18-19 (TSC).
11. Ibid., 19-20 (TSC).
12. !J:8'l Ibid., 21 (TSC);c::::::=Jnterview.OH-I0-92 (S-CCOl.
(b) (1)
OGA
DIA13. CINCPAC SSO-00021-68, 19-21 (TSCl.
14. ( T s l p i ~ t e r v i e w . OH-I0-92 (SCCOl; Deeley, 19.
15. CINCPAC (SI) SSO-00051-68. CINCPAC Operations Security Report. 1August 1968,38-41 (TSC).
16.;a, CINCPAC SSO-00048-69. Operations Security (OPSEC) Report. 1 April 1969, 1(TSC NFl; Bowman, 219.
17. CINCPAC SSO-00048-69 1-3 rrscNF).
18. Ibid., 4-5 (TSC NF).
19. Ibid., 5-6 (TSC NF).
20. (U) Bowman, 219.
21. (U) William B. Fulton. Vietnam Studies: Riverine Operations 1966-1969. (Washington, D.C.: Department of
the Army, 1973),24- 25.
22. (U ) Ibid., 26-27,42,58-59.
23...Q!B1CINCPAC SSO 00051·68, 19 (TSC).
24..fP6Hbid., 19-20 (TSC).
25. Ibid., 20 (TSC).
2 6 . ~ I b i d . , 20 (TSC); Fulton, 65-66.
2 7 . ~ CINCPAC SSO 00051-68, 21-22 (TSC).
28."'ffStIbid., 23 (TSC).
29. ~ I b i d . , 22-23 (TSC).
30. i'ffltIbid., 23-26 (TSC).
31. ~ I b i d . , 26-27,30 (TSC).
32. ~ I b i d . , 27-28 (TSC).
NO t RELEASABLE IOFOREIGN NAtIONALS
lOP $I!!(]{ET l:lMBRA 54
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,'
. ,
TOP SECk!,. ~ M S R A
33. 't"fSUbid., 28 (TSC).
34. ~ I b i d . , 28-29 (TSC).
35."'T'FSU::INCPACSSO-00021-68, 1-2 (T8C).
36. ~ b i d . , 22 (T8);I ...l
37. 't'r$Jbid.,15, 20 (T8C NF); CINCPAC 880-00021-68, 22 (T8Cl.
38.l:'rsubid., 22-23 (T8C_). ...,
39. ~ b i d . , 22 (TSCl;I ---1
40. ~ I N C P A C SSO-00021-68, 22, 24 (T8C).
41. ~ b i d . , 23-24 (TSC).
42. ~ I b i d . , 23 (TSCl;Ir-----------
43. {T$.CINCPAC SSO-00021-68, 23 (TSC).
44. ~ I N C P A C SSO 00064-70.Operations Security(OPSEC) Report. 1 December 1970,72 (T8C NF).
45. ~ b i d . , Appendix I, 1 (TSC NFl.
46. ~ I b i d . , Appendix I, 37 (TSCNFl.
47. ~ b i d . , Appendix I, 38 (TSCNF).
48. ~ b i d . , Appendix I, 38-39 (TSC NF).
49. 'l'sl.Ibid., Appendix 1,39 (TSC NFl.
50. ~ I b i d . , Appendix I,41-42, 43 (TSC NFl.
51. ~ I b i d . , Appendix I, 44-46 <TSC NF).
52. ~ B o a k interview. OH-12-92 (S-CCOl.
. (b)
OGA
W5'f KI'::LI'::A;'ABLI':: '1'6 fo'6KI'::f(':}!( K A ' f I 6 t ( A L ~
55 TOPSEeftETUM!RA
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Ib ) (1 )
Ib ) (3 ) -1 0 USC
13 0
Ib ) (3 ) -1 8 USC
798
Ib ) (3 ) -P .L .
86-36
Part IV
NSA and PURPLEDRAGON
TOP SElkE I UM8fitA
. Ib ) (1 )
lb.) (3 ) -5 0 USC
403
Ib ) (3 ) -P .L .
86-36
Ib ) (1
OGA
D
~ B e s i d e s providing/COMSEC expertise to the OPSEC branch in the Pacific, NSA
also se t about to provide dedicated SIGINT support to PURPLE DRAGON. Beginning in April
1967, NSA drafted Technical Instructions ('rECHINS) for Agency and SCA elements, both
at Fort Meade and in the Pacific, that established procedures for handling and reporting
SIGINT evidence o FCINVAJoreknOwledgeand forewarning of U.S. operations in
the Pacific.
('f80 ~ T V ) . . T h e s e TECHINS requiredall UiS. SIGINT field stations to
continuously scan their daily intercepted'unaterial for any /indications of Asian Communist
awareness ofU.S. and Allied reconnaissance/strike.-related flight. Indications ofsuch awareness
will be checked against station records for correlationwith known mission schedules. Indications
ofAsian Communist awareness of reconnaissance/strike-related activitywill be reported in the
appropriate vehicle. . . .3
Ib ) (3 ) -P .L .
86-36
NOT RELEASABLE 10 FOREIGN NAIII5I(2\LS
57 ;oP "eRET ' IMARA
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","
iOPSECReT t:JMBAA
Ib ) (1 )
Ib ) (3) -50 USC
403
Ib ) (3 ) -1 8 USC
798
Ib ) (3 ) -P . L .
86-36
!,Ib) (1 )
if',lb) (3 ) -5 0 us.i"403
5j ' Ib) (3 ) -P .L .! 86-36
( ' f ~ C NF) The TECHINS also established reporting vehicles for the enemy awarlirj.e:;s
reports, ranging from tactical reports at fla.sh precedence for intercepts which could beclosely correlated with imminent Allted operations and could be released dir.ectlytd t h units involved, to weekly and monthly Asian/Communist (later Pacific Area) Awareness
Reports, which summarized al l SIGINt evidence of enemy foreknowledge or forewarningduring t h precedin.g p : r i o ~ . 4 Over time, the TECHINS would be expanded in scope,• f i ~ s t .•.to cover mtercept indica ti ng I '" ' ' '...\ i •• •pr ion
awareness of U.S. and Allied operations and communications i n d i c a t i ~ g such awareness,
and, second, to cover all U.S. and Allied/combat ope rationa.vrather than just
reconnaissance and strike-related flights."
~ A l o n g with the new reporfiing' instructions on enemy foreknowledge and
forewarning, DIRNSA decided to replace the 'ad hoc nature of support to PURPLE DRAGON
with a more permanent mechanism to coordtnatc\the.Agency'sOPSEc-related activities
with the CINCPAC OPSEC branch. General Garter, therefore/in June 1961 established
within NSA's Office of Asian Communist Nations, thendesig'nated B Group, a B Group
Joint Task Force (BJTF) to provide dedicated SWINT support/to the OPSEC program in the
Pacific." The mission of the BJTF was "to review the SIGINT,hidences offorewarning from
all available sources, in order to deterrhine lnoton ly whafthe enemy may be exploiting,
but also how he is doing it."? A major focus of theBJTF's.Analysis of enemy awareness was
to determine whether any U.S. codes or ciphers wEtre beiilg exploited."
a ee\'), Among th e Agency organizations included in th e BJTF were
representatives of the Agency's Cornmunicaticns' Security /Division,Sl ,as well as
representatives of the various B Group branches directly involved in the Agency's efforts
aga inst the North Vietnamese, VietCong, . . targets. These
included B21, the office which had first repor ted the alerts of ROLLING
THUNDER missions. for the vastmajority of ROLLING THUNDER strikes througbBut the ini tial pt;RPLE/.DRAGON survey, and,
in fact, continued to issue them regularly light through to the termination of ROLLING
THUNDER in April 1968.1 • ../ . . /\ // // 1
for more than a year after ROLLING TH{,JNGER ended, but B21 concludedvthat most of these
later alerts were merely training e x e r c i ~ J s for the CFNVN.9
r-- ......... .......----------.. . , . ,i.:. .O-i-V-is-i-o-n-o.Jf· t ~ ~ \ ~ ; f i : : g : : { i a A ~ \ i ; I ' - - - - - - - - - . , ?45, was made the focal point for the/BJTF. B45 had
i-=''''''''''''':..;.;.o .......=''"'''''''''''lS''''c'''''o""'v''''''ery of \ //Iorganization
communications net! • ~ h a t was apparently reporting Qn/U.S. Navy,
Marine, and Air Force operations in the Gulfof Tonkin and northern South Vietnam. The
ne t consisted of a cont ro l statio and two o u t s t a t i o n ~The network was first noted active i n
....._-------------_ ....
(b)(
(b)(
'6f15eCRET t:JMBRA
NOT RELEASABLE 10 FIIREIGN NATf6KA:LS
58
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( b) ( 1)
(b ) (3) -50 USC
403
( b) ( 3) -1 8 USC
798
( b) ( 3) -P .L .
86-36
rep SECRET UMBftA
___________ ~ . , . . . . . . . . , . . T " " " " " ' : " " " ' l I A third outstation in the netl ...... ---'
IWas also identified, bu t it was seldom active.10
ONI(b ) (1 )
U.S. forces tactical data, so cal led "blue force data," to a id them in their analysisef a
hostile SIGINT target.
-a'SCT Throu hout the Vietnam conflict the Nav maintained an avera e of(b ) (1 )
analysts learned from t e data that every day at 0700 hours local, these carriers
would transmit their locations to CINCPAC headquarters in Pearl Harbor. They further
noticed that I
1 -------)T9:f R ~ b ~ l z S l t B b 8 :f a FaR818N NA'fI6HJ!!l:LS
59 Tap SECRET b1MIlRA
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3 )- P . L .
iUP SECRET (j 1'o18KA
(b ) (1 )
OGA
'-- ----IONI -5
(TSC) What they r ead surprised them. Thel Icommunications net?
d e s i g ~ a f e d l Iturned ou t to consist of reports of primarily U.S. ) i a vy and Marine
aircraft activities off the carriers in the Gulf. Some transmissions consisted of direct
transcriptions of U.S. aircraft communications traffic, no more and no less.
Bu t the element of the
He'F RELEASABLE 'Fe FeREIt'Ecf11' .J!<'FI8!\ALS
TOP SECRET ( j ~ I B R A 60
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Te, seeReT tJMBRA
communications that most surprised the NSA analysts reading them, was that everything
86,,-36 transmitted on th , ret , except operator chatter, was in English. 12
i 1 ' ~ c r w h y l Iwas in English no one could say. One plausible suggestion was
IOr perhaps they were just too' - b " ' u ~ s - y -<.-to-. - t r - a - n - s - l a - t " ' e - t - h " ' e " ' m - · ~ a - s - s - o - r - m - a - t - e - r - i a - l - - - a f - t - e - r - a - l l - , - a - t - i - t s - p - e - a.....k rlone was sending
over 2501 . Imessages a day t4 I~ M o s t of t h Iintercept observed in ! ~ e f l e c t e d activity by the
U.S. aircraft'carriers in support of ROLLING THUNDER missions and other operations, bu t
there were /also reflections of V.S. Air Force KCQ35 tanker aircraft, reconnaissance
aircraft, and B - 5 2 ~ o n ARC LIGHT missions. While most U.S. communications reflected in
I Iwere in plain tex t, B45 was able to/show that at least some U.S. operational
codesmay have been compromised, either through traffic analysis or cryptanalytic attack,
and were regularly being exploitedI .. IWhatever the m e t h o d s l ~ ~ __ ~ - : - - - - - JI lused to read the U.S. traffic, B45showed they were regularly able to intercept the
iU.S. signals and retransmit the content of t h e ~ Ion average within
five minutes/l"
~ c r r h ~ Inet continued to provide valuable intelligence to the U.S., and
important/indicatipns 04 Iforeknowledge of U.S. operations in Southeast Asia, until
late' 1970, when the. circuit suddenly/and for no apparent reason went dead. A debate
ensued as to whetherornol I----..f!P8C)"'"Other reasons for the loss of t h Isignals were also presented: the
~ a trouble getting the sys tem to function properly, and it was
......,.,p-o...s..,i'l"'b"l'"le-:"':"'thr-·...y-s...m-p"l"ly....gave up on it as being too complicated t o o p e I " a t e ~ fay
also have abandonedI . b t b ~ b e t ~ e c a u s e they had developed a bettersys tem. The c ircu it was qUickly replacedpy a parallel net using a different encryption
system.
(b ) (1 )
( b ) ( 3 ) -50 USC 403
(b ) (3 ) -18 USC 798
(b ) ( 3 ) - P . L . 86 -36
, NO I RELEASABLE 10 1"0ftEIel'I<f I(t<'fI6N'A:LB
61 Ice 51i(AET l::JMBRA
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TOPSECRET l:IMBRA
.•..•____ ~ ~ = - ' = " " " " - - : ' - - - ' I The new system remained active for approximately a year before it
too went off the air, probably to be replaced by landline.
'1TS6+-With th e loss of thel ~ 4 turned it s a t t e ~ t i o n s to other,
less valuable targets until th e end of u.s. involvement in Southeast Asia, when the
_______Idivisionwas disbanded and the target went into a caretaker status."
Whilevthe analysis and reporting of t h pet was it s major
responsibility, B45 supported th e CINCPAC OPSEC program in other ways as well. As
focal point for th e BJTF , 845 was responsible for producing weekly and monthly
summaries of al l SIGINT reflections of enemy foreknowledge and fo rewa rn ing o f U.S.
military operations.xfsecause of th e quantity of such material, this requirement was later
reduced to only weekly summaries. The BJTF was also responsible for gathering both
SIGINT and collateral (!vidence of foreknowledge of U.S. opera tions, not only by .1 _
Land even
from 1 = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = == = = = = = = = = nd forcoordinating all NSA OPSEC-related repor ts . The BJTF produced reports and briefings onit s findings for PURPLE DRAGON\team members and the U.S. military andi#telligence
communities, as well as orientation tours for personnel being assigned to the/OpSEC team
atCINCPAC. 15
(8 eeOr-As SIGINT often provided the evidence of OPSEC weaknesses, it also served as a
major indicator of OPSEC successes. Throughout the war , one of the most-common reasons
for performing an OPSEC survey of a, particular operation was SIGINTeividence that the
enemy had foreknowledge of it. In ongoing operations, such as ai r operations, the SIGINT
evidence often took the form of alert messages prior to individual missions. When PURPLE
had finished d i dati dRAGON a 1n1S e survevmz an oueration an it s recornmen ations/were irnpl emente ,
the OPSEC team would o f t e ~
'(sJI
)b)"GA
DIA
\\./</
b) (1 )
( b ) ( 3 ) - 50 USC 40 3
(b ) (3) -18 USC 79 8
(b ) ( 3 ) -P . L . 86-36
TOP SECRET tJMBRA
No'I RELEASABLE 10 FOREiGN f ~ A T I ( 5 h A L ~
62
....
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eeorrs the f inal analysis, NSA support to PURPLE DRAGON was an important,
perhaps vital element in the success of the OPSEC program in Southeast Asia. As one
employee ofB45 put it , PURPLE DRAGON "wouldn't have happened without NSA." 17
(s CeO) But NSA's support was also a success story within the Agency itself. Just as
PURPLE DRAGON was originally conceived as a multidisciplinary organization, so too was
the Agency's support multidisciplinary. In support of the OPSEC effort in PACOM, Agency
personnel from al l of the cryptologic disciplines - cryptanalysts, traffic analysts, signals
analysts, linguists, reporters, COMSEC specialists, and intercept operators - both military
and civil ian, from a variety of offices with a variety of targets, at Fort Meade and at field
stations throughout the Pacific and around the world, worked together closely to improve
the combat effectiveness and save the l ives of U.S. and Allied servicemen and women in
the rice paddies and the jungles, at sea, and in the ai r throughout SoutheastAsia."
Notes
(b ) (1 )
OGA DIA
o f ' ~
(1 )
USC 40 3
) (3) -18 USC 79 8
(3 ) -P . L . 86-36
1 I2. ke1ephone Interview with the Author. March 1992 (S-CCOl.
3 . NSA Technical Instructions ( T E C H I ~ S ) Number 4065. Report o f P O S S i b l ~ r - - - - - - - - ~ 4 w a r e n e s sofFriendly Reconnaissance and Strike-related Missions (TSC). 3 April 1967, 1tTSC l.
4. Ibid., 1-3 (TSC).
5. (Tlii lHF CCO) Memorandum for the Chief, ADSP, Mr. Oliver. Subject: OPSEC Support. 16 June 1971 <TS NF
LIMDISCCOl.6 . 131 (TSC); DIATS-SI-60IPL,47ITSCC'<n
7. ~ I b i d . , 47 (TSC NFl.
8. ~ i b i d . , 48 (TSC NFl.
9. CeCJi1-rSA I n t e r v i e ~ r - - - - - " " " " ' - - - l March 1992, witH PH-1l-92. Center For
Cryptologic History (S·CCO); ClNCPAC SSO-0001\-68, 14-15 (TSC) t lNcPAC SSO 00048-69,27 <TSC).
10.fS eeett knterview. OH-1l-92 (S-CCO); 3 / 0 0 / 2 4 5 9 6 J 0 2 1 AUG 73; 2/0c=JR04-70, 30
April 1970; 2/0c:::Ji0'j 'c67, 152130.Z NOV 67,
~ ~ ~ ~ / / fnterviBw.OH-11-92(S-CS3l; ~ t q / / ~ 0 9 - 6 7 ' 2 8 A U G U S T 1967; 2/0c::JR04-70,30
1 2 : ~ ~ n t e r v i e w . OH-1J,91<S-CCQ);N"SASerial 3 3 . 0 5 ~ . R a d i o S i g n a l Notation (RASIN) Manual.J u n e l ~ 8 , 51 ( S C ) ; 2 J O I < I R { W 7 0 3 o , ~ P B - I L 1 9 7 0 ; ? / c e : : : F 0 9 - 6 7 , 28 AUGUST 1967.
~ ; ; ~ ; . ~ 3 ~ i ~ 1 ~ g B ~ : ~ ; G I 7 c p A ~ SSO 00064 70,73 iTSC NFl; VeDa04 70,301 ~ , ~ ' P ~ . c 3 / 0 0 1 2 4 5 9 6 , 7 3 c : : : : : : : J 2 1 e - l J G 7 3 . d .. .... Fnterview. OH-11-92 ( S - C C ? ) ; I ~ ~ ; - - ~ _i t l t ~ r ~ i ~ " " ; R 6 b e r t E . N e w t o n : 7 ' h e C a p t l l r e o f t h e U S S P u e b I o a t l d t$Effecton SWINT Operations. (1992, CenterforCryptolcgfc I:Iis.t(}ryl;144-145.
1 5 l i n t e r v i e W . Q l i : l l : 9 2 ( S ~ ~ ~ ? 1 t n ~ ~ m .":,?:
(b ) ( 3 ) -P .L . 86-36
63 lOP §[ERET tJMSRJ\
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16. ts=eeef tnterview. OH-11-92 (S-CCO>.
17.4 eeerIbid. (S-CCQJ.
1 8 . ' " t t t - e e ~ Ibid. (S-CCO).
(b ) ( 3 ) -P .L . 86-36
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(b ) ( 1)
OGA DIA
IUPSECRE r tJM81\A
VCINVA INTELLIGENCE STRUCTURE
- ' T ~ eeen- At the top of the VCINVA intelligence structure was North Vietnam's
Central Research Directorate (CRD) in Hanoi. The CRD, sometimes described as "Hanoi's
DIA," had responsibility for strategic, national-level intelligence." Below the CRD, the
Central Office, South Vietnam (COSVN), analyzed and disseminated tactical intelligence
to VCINVA forces throughout the RVN and served as a point of contact between the CRD
and uni ts in the field. 7 Finally, scattered throughout the RVN were VC/NVA tactical
units and indiv idual agents. They could either pass their information up to COSVN for
analysis or, in some units, analyze and use it for tactical advantage thernselves.f
~ O all sources of information, the VC/NVA valued communications intelligence
most heavily, with enemy PWs and ralliers describing it variously as "the easiest, safest,
and fastest" means of obtaining intelligence, and as a "continuous source of information"
on All ied plans and operations." All level s of the VCINVA intelligence system were
involved in the collection, processing, analysis, and production of COMINT. The CRD in
Hanoi, for example, attempted the cryptanalysis of medium- and high-level U.S.
cryptosystems. While there is no evidence the Nor th Vie tnamese had any success
cryptanalyzing high-grade U.S. systems, the CRD was successful against some lower
grade codes and ciphers, such as one used to transmit airborne radio direction finding
results in the RVN. 10
( ~ T F ) Much of what is known about VC/NVA COMINT activities in the RVN comes
from documents and personnel captured during Operation TOUCHDOWN in 1969. During
TOUCHDOWN, soldiers of the 1s t U.S. Infantry Division in Binh Duong Province near
Saigon managed to capture twelve of the eighteen enemy personnel assigned to a local
Technical Reconnaissance Unit (TRU), a VCINVA tactical COMINT uni t, a long with i tems
of equipment and some 2,000 documents."
~ B a s e d on th e review of TOUCHDOWN-related materials, as well as
interrogations of enemy PW sand ralliers, it was clear that the enemy maintained an
extensive and efficient COMINT network in th e RVN. COSVN, through i ts Military
NUTRELEASABLE 10 PURitGN NA I IeJI4"}(LS
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~ - . ~ . ' . , ; .
. :
.-'-'
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Intelligence Bureau (MIB), oversaw the activities of at least 4,000 enemy personnel in the
RVN estimated by CINCPAC to be engaged in the inte rcept and ana ly sis of Allied
communications in 1969. The actual number may have been as high as. 5,000 personnel.
The extent of the enemy COMINT effort inside South Vietnam was particularly shocking, as
the best previous estimates of the enemy's COMINT effort had suggested that no more than
300 enemy personnel were engaged in COMINT activities inside South Vietnam.V Enemy
TRUs were apparently established in every part of the RVN and ranged in size from 406
personnel in t he 47th Technical Reconnaissance Battalion colocated with COSVN along
th e Vietnamese-Cambodian borde r in early 1967, to individuals performing signals
intercept operations alone in Saigon."
OPERATIONSOF THE TRUs
;er ' l 'he TRUs used a combination of captured and stolen U.S. radio equipment, as well
as commercial equipment from Japan and Western Europe, and radios supplied by the
Communist Bloc countries to conduct intercept. They also used small, battery-operated
tape recorders to aid them in exploiting non-Vietnamese voice communications. 14
DRV signals intercept officer at work
MOT j;{i2bi2 \g '\8'"'8 ' fO FOREI8!1 N J l c ' f I 5 N ' i i L ~
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of enemy intelligence during t he war in Southeast Asia. The VCfNVA also maintained an
extensive espionage program in the RVN and perhaps elsewhere in the Pacific. Individual
agents working in the RVN were controlled by Military Intelligence Sections (MIS), which
were directed by the Strategic Intelligence Section (SIS). The SIS reported directly to the
MIB at COSVN, where agent information was ana lyzed and either disseminated to
military units in the field or passed on to the CRD in Hanoi ;" There was also evidence that
VC/NVA tactical units recruited their own agents to provide them with local, tailored
intelligence.
""'(C}The VCfNVA were able to infiltrate agents into al l levels of RVN society, from
high- rank ing mil itary and civilian personnel in Saigon to peasant children in the
countryside. The enemy also attempted and, often it seemed, succeeded in placing agents
among the Allied forces, especially the Americans, usual ly as workers in local military
ins tallat ions . The enemy typically sought communist or DRV sympathizers to recruit as
agents but were not unwilling to resort to threats and violence to coerce people into spying
for thern.:"
~ I n t e r r o g a t i o n of enemy PWs and ralliers gave general indications of VC/NVA
espionage in the RVN. Fo r instance, sympathetic civilian authorities often provided the
VC with information on Allied troop concentrations in their areas, while local villagers
would provide t hem with local hearsay on Allied intentions.:" Villagers were a lso
responsible for warning the VC of Allied ac tivi ti es . These v il lagers would use "such
methods as ringing a gong, shaking a rattle, firing shots into the air, blowing a whistle,
beating a bamboo stick, blowing a horn, setting a fire, or igniting smoke grenades" to warn
the enemy of Allied t roop movements. The VC/NVA also would force interpreters and
translators working for U.S. mili tary and civilian agencies in the RVN to steal documents
and provide information from their jobs."
-t€'r1'he enemy also made a concerted, and successful, effort to infiltrate ARVN units inorder to provide more timely and accurate information on proposed ARVN operations.
Often, draft-age VC personnel would allow themselves to be arrested as draft evaders, and
would then volunteer for duty in target areas. VC/NVA personnel even gained access to
ARVN-controlled installations by wearing captured or stolen RVN armed forces uniforms
and passing themselves off as South Vietnamese military personnel. 33
~ ?fFt When the enemy was not able to place an agent inside a particular Allied
installation, they settled for placing one near the installation or in those places that Allied
personnel were known to frequent off the job, and relied on observation and eavesdropping
to gather information. The enemy recrui ted vendors, truck drivers, carpenters, even bar
girls and prostitutes to serve as agents." The VC was even reported recruiting fourteen- to
sixteen-year-old children to hang around Allied radio-equipped vehicles and copy the
frequency settings on the communications gear, and th ey ar e believed to have placed
NOT REI §; A A ~ b 'FQFQFUH6N N k ' T ' 1 6 r ( 2 \ L ~
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(b ) ( 3 ) -P .L . 86-36
DIA
(b) (1)
OGA
Notes
he Great Conversation, 5 .
2. (
3. CINCPAC Serial SSO 00026-71. Operations Security (OPSEC) Report. 1 June 1971,2 (TSC).
4. ;e(Combined Intelligence Center Vietnam (CICV) Serial MACJ231·6. VCINVA Alert an d Early Warning
System. 30 June 1970, i (C).
5. ~ I b i d . , 1 (C).
6. CINCPAC SSO 00048-69. Operations Security (OPSEC) Report: Extracts from Appendix I, 3 (C);
Lieutenant General Marshall S.Carter, DlRNSA, Memorandum to Director,Central Intelligence Agency, Chief,
JCS, and Director, DlA. Subject: Project RATHSKELLER. 12 January 1968 (TSC).
7. CINCPAC SSO 00048·69. Extracts from Appendix I, B-1 (C); Department of Defense Intelligence
Information Report <DODIIR} Serial TCSR PAC 08-70. Study ofVCINVA Technical Reconllaissance Units, 14
July 1970, 2 <C).
8. ('l:'s..CINCPAC SSO 00048-69. Extracts from AppendixI,B-1 «».
9. ~ C I N C P A C SSO 00048'-69. Extracts from Appendix I, 4 (C); DODIIR Serial 6 028 2422 68. Prior Knowledge
ofAllied/U.S. Operations. 22 June 1968,2,3 (Cl.
10. ~ DlRNSA Memorandum to Director CIA. Chief. .rCS. and Director. DIA.Serial N0040. Subject: Project
RATHSKELLER. 12 January1968(TSC); I \ I11. ~ C h a r l e s W. Baker. "Military Effects of Poor Communications Security (COMSEC) --Some Historical
Examples" (unpublished.manuscript), (1991 , National Security Agency, Center for Cryptologic History), 3,4 (TSC
NFl! ,"Viet Cong SIGINT and U.S. ArmyCOMSEC in Vietnam." CRYPTOLOGIA, Volume
XIII, Number 2, April 1989,144- 145.
12. ~ ) o O D I I R TCSR PAC 08-70, 2 (C); (ClCINCPAC SSO 00048-69. Extracts from Appendix I, 1 (Cl; Boak
interview. OH-12·92 (S-CCO).
I3.-te7CINCPACSSO 00048-69. Extracts from Appendix 1,1, B-2 «»,
14. JKj Ibid., 3 (C); CICV MA-CJ231-6, 2 (C).
15. ~ eOOl DODIIR Serial TCSR PAC 15-69. Study of VCINVA Technical Re.connaissance Units (TRUJ. 18
November 1969,2; 3 (S·cCO); U.S. Army Security Agency (USASA). TAREXReport TCSR 04- 71. VCINVA
COMINT Effort. 8 March 1$71,5,7 (C).
16. (C CGO) USASA TAR.E· XReport TCSR 04-71. .5, 6 (C); DODIIRSerjal TIfR RVN 24-68. Interrogation ofLeVan Ngot, 4 November 1968,3 (C-CCO); DODIIR Serial ' VC Communications in MR2. 14
January 1968,2 (C). 1
1 7 . ~ U S A S A TCSR 04-71. pg.4, 5 (C); CINCPAC SSO 00048-69. Extracts from Appendix I, 3 (C).
18. ¢>Ibid., 2 (C ) ; c= J l45(C) .
19. CINCPAC SSO 00048-69.Extracts from Appendix I. pg.3, 4 (C).
20. (0 600) DODIIR TTIR RVN 24-68, 4, 5 (C-CCO); DODIIR TIR RVN 307-68. VC Operations to Obtain
InformationFromARVN an d Allied Forces. 31 December 1968,4 (C-CCOl;L:]145(C).
21. -t6 cew USASAPAC TCSR 04-71 4, 8 (Cl; DODUR TCSR PAC·15-69. Study of VCINVA Technical
Reconnaissance Units (TRUJ. 18 November 1969, 3, 4 (S-CCO); TAREX Reports. 15 June 1970, 1 (S).
22. ~ C I C V MACJ231·6, 4 (C); DODIlR TCSR PAC 08-70, 5 (C).
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23. ~ D O D I I R IR 6028013868,2 (C).
24. i s S S ~ D O D I I R TTIRRVN 24-68, 6 (C-CCO); DODIIR TCSR PAC-I5-69,3 (S-CCo>.
2 5 . 1 t r C C ~ DODIIR TTIR RVN 24-68, 4 ( C -CCO )D4 5 .
26.1C-Ce8rDODIIR SerialTIR RVN 308-68. Monitoring ofARVN and Allied Radio by the VC 186th Battalion. 3
December 1968,4,5 (C-CCO).
27. ~ O D I I R T C S R P A C 0 8 - 7 0 , 6 ( C ) .28. (S SSQl DODIIRTTIR RVN 24-68, 5 (C-CCo>.
29. DODIIRTCSR PAC 08-70, 2 (C).
30. f€tCICVMACJ231-6,5 «».
31. DODIIR Serial IR 6 028 2730 68. Prior Warning ofAllied Operations. 11 July 1968,2,3 (C); DODIlR IR
6028013868,3 (C).
32. ~ I V C MACJ231-6,5,6 (C). (b) (3) -P . L. 86-36
33. ~ Ibid., 6 (C).
34. (SG ~ f F l Ibid., 5, 6 (C};Donzel E. Betts. The Front 4 Intelligence Threat Puzzle lDraft Copy). December 1971,
161SC NF).
35.ietUSASAPAC TCSR04-71, 7 (C); CICV MACJ231-6, 3 ( 0
DIA
" (b ) (1)
OGA
36. (SS ~ f F l DODIIR TCSR PAC 08-70, 21C); Betts. The Front 4 Intelligence Threat Puzzle (Draft Copy), 16 (SCNF).
37. J£!)TAREX Reports, 1 IS); DODIIRserial IPriorJ(llOwledge ofAlliedJU.S. Operations. 22 June1968,2 (S).
38. ~ D O D I I R I IDODHRTTIRRVl\i24.SE,6(C}.
3 9 . ~ C C DODIIRTIR RVN 307-68,3 (C-CCO); TAREX Reports,'VSL
40. ¢DODIIRI I41.J2"Ibid., 2. (C); TAREX Reports, 3 (S).
NOT REI EASABI E TO F O R I i : I Q ~ f ~ f A ' F I 8 N A h S
73 TOP SECRET U r o ' l ~ R A
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PURPLE DRAGON: LESSONS LEARNED
DIA Ib
OG
(U) On 27 January 1973, representatives of the Uni ted States, Nor th Vietnam, South
Vietnam, and the Viet Cong signed "An Agreement Ending the War and Restoring Peace
in Vietnam" in Paris. The agreement called for the withdrawal of the last 23,700 D.S.
troops and advisors left in South Vietnam by the end of March. Although U.S. servicemen
and women would continue to be actively engaged in Southeast Asia for another two years,
the Paris Peace Accords effectively marked the end of the Vietnam War for the United
States.
(D) By the end of the war, PURPLE DRAGON and the U.S. operations security program
were a little over six years old. During that time, what did the U.S. military learn from
PURPLE DRAGON? And how successful was the U.S. OPSEC effort in Southeast Asia?
PH¥Y' RSbl.'h4i:St\BLI3 'f a FaR13I6N Nlc'fI6H'lcLS
..
81 ";OP SeeRE i UMBRA
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TO,. seeReT tlM8RA
CU) When U.S. military co mman der s f i rst received proof from t he N a ti on a l S e cu ri ty
Agency t h at th e enemy was forewarned of U.S. operations in Southeast Asia, no one coulds ay w it h certainty how he ha d obtained his information, and, w it h ou t k no w in g t hi s, there
was no wa y to prevent hi m from obtaining more. I t was in order to discover how t he e ne m y
o b tai ned h i s i n fo r mat io n , an d to p re ve n t h im from obtaining more, tha t PURPLE DRAGON
was born.r----------------------------------, (b) (1l o
Tap SECRET tlM8R"A
NVI R E L E A ~ A e L ~ T ~ f 'eftEI6N NA'f'fOUALS
82
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31. ;.81"CINCPAC SSO 00054-71,188 (TSC NF).
32. iS€) } t CINCPACMessage 7349 to MACV 300136Z JUL 72 (S); JCS Messa e 0020 to DIRNSA 261639Z
JUL 72 (SC); JCS Message 0021 to CINCPAC 261641Z JUL 72 (SC); SA 86 , Memorandum to
Captain Smith, JCSJ34. 23 August 1972 (SC); CINCPAC.Operatio'l8 ecunty eport, T ~ A to Appendix II. 1
December 1972,8 (SC NF).
33. !knCINCPAC. OperationsSecurity Report, Appendix II. 1 Jun!i!1972. pg.I-5 (TSC).
34. ~ S Pacific Representative in Vietnam, Message to DIRNSA. 300702ZAUG 70 (TSC).
35. S12'l St. C. Smith, Chairman,OPSECMonitoring Group,Memorandum (C).
36. }P'l Ibid. (C).
37.;Q1 Ibid. (C).
38. fJ/f) Ibid. (C)c::::::::J.nterview; Deeley, 19.
39. NSA PacificRepresentative in Vietnam Message to DIRNSA. 300702Z AUG 70 (TSC).
40. linterview. OH·11-92 (S-C.cO); St . C. Smith, Chairman, OPSEC Monitoring Group,
Memorandum (C).4 1 . ~ - - - " " ' - " " " ' - - - - - - '
(b) (1)
OGADIA
(b ) ( 3 ) -P .L . 86-36
NOT Rf'! EASAB! E TO EQRE!c.N NATWNAI S
87
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,
-"
..
Part VII
PURPLE DRAGON at Peace
OPSEC AFTER PURPLE DRAGON
~
m,. SECRET l:JMBRA
\(b) (1 )
OGA
DIA
CD) Therefore, it should not be surprising that the surveys conducted by these OPSEC
branches often showed a lack of understanding of the purpose of operations security. In
wo:r RIkJ"i:' $ j' gJ"i: TO F O R J i ] I € ~ f ~ f H f I E m ! d " S
89 TOPSEeftl!!!T tJMBRA
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: ~
TOP SEERET liMBRA
Vietnam, it had been possible to recognize what information the enemy had wanted and,
by surveying operations, to discover whether that information was being divulged and
how, ifpossible, to prevent it. Away from Vietnam, however, many OPSEC surveys, often of
such operations as wa r game exerc ises , l acked a clear-cut enemy with ident if iable
intelligence interests. In these cases, OPSEC survey teams merely recorded potential
security violations during the exercise, without regard to whether the lapse could have !(b)been exploited by an enemy, or whether it might be correctable, or even whether the 0'
information so divulged would have proved of real interest or value to an enemy.s
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(b ( 3 ) -P .L . 86-36
lOP $I!(RET ~ M I I R A
< Ihas been an i ! l ~ e l l i g e n . c.. eaIlaly.s...t. in the Office
0\~ ( B 5 ) since March 1993.
Pr-evioualyvfrom January 1990 toFebr-uary 1993,he was an
Intelligence Research intern. From 19S7 to 1990 he was a
Secur-ity/Protective Officer with NSA, and from 1984 to 1 9 ~ 1 7 DI Iwas employed by the Federal Bureau of Investigation .
He did research for and wrote this s tudy\while .on a tour with
h n r f. r r tolo ic Histor in 1992. h I
He is professionalized as an Intelligence Research Analyst.
(
(b) (1)
(b) (3 ) -50 USC
(b ) ( 3 ) -P .L . 86
NO I R E L E A ~ A ~ L l ! : 'Fe f 'efttJI8N NltTI8NAI"S
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"Fep SEERET tJMBRA
DOE
DRV
EAGERYANKEE
ECM
FAC
FOCUS RETINA
FRAGORDER
U.S., Department of Energy
Democratic Republic ofVietnam (North Vietnam)
U.S. coverterm for amphibious assault landing, RVN, 1968
Electronic countermeasures
Forward Air Control
U.S.lROK coverterrn for joint training exercise, ROK, 1969
Fragmentaryorder
(b ) (1 )
( b ) ( 3 ) - 50 USC 40 3(b ) ( 3 ) -P .L . 86-36
HEAVYARTILLERY U.S. coverterm for B-52 strikes
HUMINT Human intelligence
lOSS U.S., Interagency OPSEC Support Staff
JCS U.S., Joint Chiefs of Staff
JGS RVN Joint General Staff
L/H HOUR Helicopter landing/assault boat landing hour
MACV U.S. Military Assistance Command, Vietnam
MAF Marine Amphibious Force
MARKET TI:vrE U.S.lRVN coverterm for coastal interdiction operations, RVN
MIB DRV, Military Intelligence Bureau
MIS DRV,Military Intelligence Section
MRF Mobile Riverine Force
MSD RVN, Military Security Directorate
NCS NSA, National Cryptologic School
NOAC U.S., National OPSEC Advisory Committee
NOTAM Notice to Airmen
NSA U.S., National Security Agency
NSDD National Security Decision Directive
NSG U.S., Naval Security Group
NTDS Naval Tactical Data System
NVA North Vietnamese Army
OPSEC Operations security
PACOM U.S., Pacific Command
NOTRELEASABLE 10 l"5IU3I6U H l r ' f I Q ~ r A IS
"FOP SECRH t:lMBRA 96
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T9P S"RET !IMARA
PFIAB
POINT JULIETTE
PRC
PURPLE DRAGON
U.S., President's Foreign Intelligence Advisory Board
U.S. coverterm for B-52 and RC-130 rendezvous point west of the
Philippines
People's Republic ofChina
U.S. coverterm for the first CINCPAC OPSEC survey, 1966-1967,
and unofficial coverterm for CINCPAC's permanent OPSEC
branch,1967-1973
PW
RALLIER
Prisoner ofwar
VCdefector
(b ) (1 )
( b ) ( 3 ) - 50 USC 40 3
(b ) ( 3 ) -P .L . 86-36Republic ofVietnam (South Vietnam)NSA, Communications Security Division
U.S., Strategic Air Command
U.S., Service Cryptologic Agencies
U.S., Senior Interagency Group for Intelligence
Signals intelligence
DRV, Strategic Intelligence Section
Special Landing Force
Signal Operations Instructions
U.S., Strike Command
U.S. coverterm for amphibious assault landing, RVN, 1968
NSA, Technical Instructions
Task Force
Tactical Operations Center
Time Over Target
U.S. coverterm for U.S. Army operation resulting in the capture ofa VC/NVA TRU .
ROK Republic ofKorea (South Korea)
ROLLINGTHUNDER U.S. coverterm for fighter-bomber bombing raids-against DRV,
1965-1968
RVNSl
SAC
SCA
SIG-I
SIGINT
SIS
SLF
SOl
STRICOM
SWIFT SABER
TECHINS
TF
TOC
TOT
TOUCHDOWN
TRU
U&S COMMANDS
UTM
VC
DRV, Technical Reconnaissance Unit
U.S., Unified and Specified Commands
Universal TransverseMercator
Viet Cong
!(tl'f' IUlLrJA:S/rBbEJ 'TO FOag[QPT ~ r! TlQN 4 I 5
97 T9P SECRET UMBRA
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fe, SECREf UMBIbIt
Bibliography
!(b) ( 3 ) -P .L . 86-36
Books
Betts, Donzel E. , et al. D ~ a d l y Transmissions: COMSEC Monitoring and Analysis.
National SecurityAgency, CiyptologicHistory Series, 1970, (S NF).
Betts, Donzel E., et al . Working Against the Tide (COMSEC Monitoring an d Analysis).National Security Agency, OryptologicHistory Series, 1970 (TSC NF).
Bowman, John S., General Editor. Th e World Almanac o f the Vietnam War. New York:World Almanac, 1985.
Fulton, William B. Vietnam Studies: Riverine Operations 1966-1969. Washington, D.C.:Department of the Army, 1973.
Lancaster, Bruce. Th e America1'/. Revolution. New York: The American Heritage Library,1971. . .
Newton, Robert E. Th e Capture o f the USS Pueblo an d Its Ef fect on S lGI N T Operations.
Center for CryptologicHistory,1992 (TSC NF NC).- - - = - = - ~ ~ = - = - __: - - ~ : : - - " r T h e Great Conversation: Th e Origins an d Development o f the
National Operations Security Program, Interagency OPSEC Support Staff, 1991.
Sun Tzu. The Art o f War. Trans. Samual B. Griffith, London: Oxford University Press,
1963.
Wallace, Willard M . A p p e a l to Arms: A Military History o f the American Revolution.
Chicago: Quadrangle Books, 1951.
Articles
Deeley, Walter G. "A Fresh Look at PURPLE DRAGON." Signal, Volume 38, Number 8,
April 1984.
1973 (TSC).
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Sawyer, E. Leigh. "Pursuit o f t h ~ r - - - - - " " I Cryptolog, Volume IV, Number 3, March
1979 (TSC).
1 " , , " " , : - = = ~ = = : = : - : - - - - , r " H i s t o r y o f a Dragon." Dragon Seeds, Volume 2, Number III, September.
I..
History (S CCO).
(b ) (1 )
( b ) ( 3 ) - 50 USC 40 3
(b ) (3) -18 USC 79 8
(b ) ( 3 ) -P . L . 86-36
99 TOP SECAHblM8RA
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fOP 5!CItI!' l::JMBRA
1\ Interview w i t ~ OH-10-92, Center for Cryptologic- - - - = ' H : : " : ' i s ~ t o - r y - - - - : ' ( S = C - : : : C - : : : O - : - ) . . . . . . L... - - - - I
Other Interviews
NSAProduct
3/00/24596-7 1 2 1 A u g u s t l : : ~ .2I004-70,3? i \PI" i l197m
2J 07'67, 152130ZNove'b
er 67.3/ 09-67,28 August 1967.
' ( b ) ( 3 )- P .L . 86-36
(b ) (1 )
( b ) ( 3 ) -50 USC 40 3
(b ) (3) -18 USC 79 8
NSASources
____ --'!NSA B6, Memorandum WCaptain Smith, JCS J34, 23 August 1972 (SC).
Baker, CharlesW. "Military Effects dfPoor Communications Security - Some HistoricalExamples," (unpublished manuscript) 1991, Center for Cryptologic History (TSC NF).
Betts, Donzel E. The Front 4 Intelligence Threat Puzzle (draft copy), December 1971 (SCNF).
~ . . . . - - - - - : _ - - - . J I C h i e f Sll,\Memorandum to\Distribution .. Subject: COMSEC Thinking of
ExperiencedD;S. ServiceOfficers Assigned-to Vietnam, 18 April 1972 (S CCO).Carter, Lt. Gen. Marshall S;, DIRNSA. Memorandum to Director, CIA, Chief , JCS, andDirector, DIA. Subject: ProjectRATHSKELLER\ 12 January 1968 (TSC).
Chiefof Staff, NSA, Memorandum to Deputy Director, NSA. Subject: OPSEC Task Force
Report. 10 May 1988 (S NFCCOr \
Director for Operations Security, NSA,OPSEC erie£. 1992.
Director for Operations Security,NSA. Chronology of Pre-1984 OPSEC Events andDocumentation. (S NF). . . ,
Director, NSA. Memorandum to N S A R e p r e s e n t a t i v ~ , Pacific Command (NSAPAC), 9August 1966 (SCCO). . . ,
L. . . - I M E l I I 1 ~ r a n d u m t ....', ~ May 1993.
National Security A g e n c y , M e m 9 ~ a n d u m for theChiH, ADSP, Mr. Oliver. Subject:
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(b ) ( 3 ) -P . L . 86-36
J'TQT RgU A lilARhi TO fORiTCN NATION A S
100
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T9P SEERI!T l1MBRA
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JCS Message 0020 to DIRNSA, 261639Z Jul 72 (SC).
JCS Publication 3.54. Joint Doctrine for Operations Security, 22 August 1991.
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Smith, St . C. Chairman OPSEC Monitoring Group, Memorandum to Distribution.
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CINCPAC 8S0-00026-71. Operations Security (OP8EC) Report, 1 June 1971 (T8C).
CINCPAC 8S0-00064-70. Operations Security (OP8EC) Report,l December 1970 (TSCNF).
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CINCPAC 880-00051-68. Operations Security (OP8EC) Report, 1August 1968 (TSC).
CINCPAC 880-00021-68. Operations 8ecurity Report,l April 1968 (T8C).
TOPSECRET l:JM8ftA
N8'f RFJLFJASABLFJ 'f 8 r8RFJlON NA'ff8NALS
102
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.--.'
TOP SECRET