~ 

SE~U:-:ITY J•'t:=GRMAT:Mf ID: A53979 EO 3.3(h)(2) 

PL 86-36/50 USC 3605 

1·ur, S~SCF<ET'!;_~_ffif)E 

tO? S~ ~ SllSf:JRPlY lm'OftMA 'ftc!I 

c 0 p ?' 

'fO t AFSA..020 

FROM• AFSA-23D.3 

VIA.1 AFSA-2301 il'SA-23 

SUBJro'ra P1ain Text 1Xplo1tat1.on in the Chinese Military ProblEA 

Since the aotivaU.on or the Chinese CC11"11t1Ul'liet problem. at >.FSA in mid 

l949, a l..arp body of intormaticn ha.A been iprcduced on Chinese Communiet 

MU1tar.r forces. From the etardpoint or b.· .oth qu.alit1.• am amount, 'rl.rtu.ally .:U. or this intormati.on has been derived rrom an ana.lysis ot plain text. 

messages. In the period 15 Juno l949 to 5 March 19.52, al.most Bo per cent 

or all lldJ.itary 1dent.U'ications vere pro'rldcd by plai.n text tra!fic - largel.y by personal messages on the Camnercial Network. 

Chinese Cammlllist Milit~dentifieations 

· {I'S June !949 - S / fi !952) • ... 

source 

Comlnere1d let Plain 

Text Traffic 

Enciphered Trattic 

Total 

GR.CURD FORCES1 

lumber or Identllicat1on1t 

325'1. 

Per cent 

o.r Tot.al 

78% 

ilthougbl ltrat.fic currently 

provide identiHCatlon or ta.ctlcil ilrilts iii Korea, Virtually all 1dent1-

ri.c"Uons o! Chinese Communist Groum. Force tactical units in China proper 

(Field Armies; Amy Groups• Armies aIJ1 DiVisions) are derl:red exc1wrl.vely 

from plain text I !/ 

Maximum .Jftmi>er and Percantaee Number arxl Percentage 

lluniber Identified bom Idenillied !ram 

Echal.on ot Units Plain Text J'la1n Text an:1 Ci~~ 

FUl.d Armies 4 4 ~100%) 4 roo;;) 

Arrq Oroups 22 14 

m~ 14 64%) 

And.es 70 4l 46 6S%~ DiTiaions 210 :;1 85 (40t 

y I !lrd!rr ot Batre~ Chi'!e•e Ccmm!un1st .~~. Fo.r:ces, 4 December 1951. 

TOP s::CRET f , __ ,p~p:: -- Aff" t-

--p-e-c 1-as-s--if-i e_d_a_n_d -a-pp-r-ov_e_d __ f_or-r-el-e-as_e_b_y_N __ S ...... A-on-0""'"5"""""_--30---2--01_4_p_u r-s-ua_n_tt_o.....,E""""". o-. 1--3-5-2a -
REF ID:A53978 

f[t=o·3.3(h)(2) 

lf>L 86-36/50 USC 3605 

Slgnifieantly, the great bulk ot COMIRl ai{]]unita above division 

l.Pel. is available only trm plain text ~f':i.¢. Plain ~ mUitaey 

kt enti!'ie a t..1.ons hae proVided intellig~e/ at pa.rtlcu.lar htt~u~st 1 

(a) First identU'ications o! the. lllO. 'V .•eme .. n .....t ot·ITlmf··· .•. \. te t'rom south 

Cbi:nA tovam Manchuria,, reported in July.~. y (h) Further indications or movement ani 1dentit1cation o! units 1n 

Manchuria. }/ 

The above reporto vero issued .Prior to the Chinese C<ximuniat largetroalo intervention 1n the torean war. 

(c) t:Lrst imications that iel«tents ct the Fi:ntt au:l Second Field 

Armies 1fe1"e enroute to/ Korea, pre.4-at.ing tJx>nt-line identil'ica-

(d) =t ~a:l~~e a~ 8i:e "!:~t o¥the 16th .Amlt or its al.ement.s 

to Manchuri& .trom. So\ltmrest China. 51 • ··. • \ 

(o) Increase in the lev-el ot rid.lltaey unit .1dentU'icat1om in South 

China by solution,/ through plain• text tratrl.c,. o! military un1 t 

c.over-destem tions. §/ 

In brle.t, 1.dentificationa iot Chinese Qemuun1st inllitar;r units providfd by plain text tra.rf.ic furniSh most ol tho COMlliT 1ntomat1on an the 

disposition and moYeJllellt/or too Chinese Communist Groum Forces in China. 

Pl"Cpcr am Manchuria, Ja()st or/ t.ha COMM lnt'orma.tion • .. on llUitar;y d1strict. 

organisation in China, /the orp.zdzation of var.taus millt-.ry headquartora 

eahelon3., tm location.s arrl .act.1:rities or mUitary ach()()l~J &111 most o£ 

tbe COMINT 1.nrormation on in:Uitaey supplt mattsrs. 

AIR 

- The foundation o! all. u.s,. estimates ot .Air Ol'det or Battle in China 

am ManehUl"ia rests wholl.Y on AFSA plain text report.3. SolutiCJl'l ot the 

!I ~YBl!lCirt. .~i Fourt_h/~ield A!?l un1ts_.. l7 July 19!>0, L-1 _____________ ____. 

}/ MoVement. ot !'ourth.i F~ld Army U./ntt·"'.·· Bo. 21 l Septemborr-· _····· •...;..;.;19;..:;$0--11.1.,l __ ----' lo. !iS; '!ovement tit' SO ~~i!a, lJ NOV'f:llllbar 19?'01 1...I _____ __. 

W JlkNeme.nts at Fir. st F. ield A:nJV.•Elernen .• · .··ts_., S P'ebruar.y 19,l,._I -..---------' ~IWlJ.urrOiit 15Iapos-,=~ <)?~~Pi~ A!N Elem~s, 

ZI r=]l6th 4.in !it~ohurla ' -: [o:r:-ea,,Tbeatre,, 14 February 19S2, 

§/ cod ... 'iur::i>erin , 2~ sept.ember 1951, 

s 1n South China 

--- -- -- ----=~- - -------
RE.F ID :A5397B 

,. 

TOP SECRETSYEDE 

'i9P 618RB! StimK -

11;,YBt&n at cover-nu.:!bers uasl by tactical air units mld.e clear tho' reg.t-

•nt - division relationship am was essential to aubaaqJent interpretation which 1nc1med enciphered air trai'tie. Y 

J'irst CCKilfl id.entit1Cat1.ons or the Fourth Air Regiment, tbe 27th Air 

Regiment,. the )rd,, 5th al'ld 18th Air Divisions came trom plain text tratf'ic. 

Pi.rat. reterea:e to air t.raining school.a appeared in pl.ain text :l.n 

August, 19SO and for.ax:d the b&G1s tor aalut.1.on ot the Fll&ht School coverdesign..'ltion ll)'Btem :and idrmt:l.f'icat.1.on ot ~cola. §/ 

With current! J pl.a!n text pro- vides important auppiementar;r lritorn;atton on air iiiiits China and 

pneral. support to the intelligence ef'tort. 

EO 3. 3 I h I I 2 I 

RAVAL PL 86-36/50 USC 3605 

Dcept tor lim1ted Werma tion 'ya,Uable .t.tom a mall amou,nt ot i•Yal 

• trattic passed I _.· / l •irtual.ly aU camrr intor-.tton <>n 

the I f.: deri vecl bom plain text messages passed on 

the COillliorc181 llrivoi"k. Th includes infOl'Jllation on command organiu.t1on, 

INSEPARABILITY rP PLAIN TEXT AND ENCIPHERFD TRAFFIC PRC-C&35Dl0 

While plain text trat.fia proVides extensive COMM 1n1"0l'lnil.tiott\ on 

Chinese Co:'llN.ni8t military unit.a am orpnlsations -- in llW'lY" oases \mosii\.or 

1111 of that intorma.t1.cm - urder no a1rcumstances can t.he processing\ atd 

analysis ot pl&1n tat link activitq I...__ __________ ___.. _ __, To do so llOul.d damage not only the technical. camrr ef'tort but aer1oual.y 

inhibit the product!cm ot intelligence from intercepted comun:tcatton•• 

Prooa31ng ot rar Ba.st. targets is based on the recognitim that c1"3Ptanalysi a, tram.a analys1a w linguistic cploi tation are mu tu.ally depllnd. - ent am t.ha1i the purpose or eaoh,. together,, 1a to provide the mu:imUM. contr.1.bu.tion possible to the reporting or intell.:lgence operation. 

Intcrmation deri.Yed h'om the dq-to--dq processing ot plain text by 

analysts has enablod thoso anal,ysts to accompllsh ant hasten sol11tion ot 

encipherai traf'r11:. 
REF ID:A53978 

TOP S~~a<ET ri rs:oE ml'~ :69EBB 

/ 

EO 3. 3 I h I I 2 I 

PL 86-36/50 USC 3605 

Ntlton Zaslov. ~~-2JlJ) 
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1S 1* SC> 

1$ Jiu> 51 

lSJva.51 

1' D80 $1. 

JI. Oct. so 

J5 Dec so 

JS Kar 51 

lS Jun SJ. 

I& Dae 51 

ll OC\ 50 

JS Dea so 

1$Ku>S1 

JS J1m Sl 

4n. Sl 

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REF ID:A53978. 

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