t; REF ID:A414BBB5c 

.~~~bNA 

~W/l/Cl/, ~-$If' @¢-,,,A<~ten,t;oj'-fi,,;,l!c1tJ Sept .24 1 1919. 

From: George Fabyan, 160 W. Jackson Blvd., Chicago, Illinois. 

To: The Chief Signal Off~cer of the Army, Washington, D. c. 

Subject: Printing ·Tel-egraph Ciphers. 

Your conununication of S~ptember 19th,with enclosures 

as stated, was received. Diligent, conscientious work, consistent with the importance or other work we have on hand, - - -

will be ms.de on the problems presented and the result, if ... any, reported to its source. 

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@'pp roved for Release by NSA on 11-18-2014 pursuantto E .0. 1352a 
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REF ID:A414BBB5 

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, R DEPARTMENT ~ 0 

WA Ch' f Signal Officet . ; . ~of the. ie -... Washington 

[ l• W1th :ref•reme to Olli' letter at Qeptember :ca. ·then 

are tor-.*4 l~u,,w.tth one hq4re4. $14 tldi-tf'll':l'lv• cipher tapes prepared 

trom the 'total mmibe_I' -ot naee1ages ac.ttta.111 ~t 4111, on$ 4r;w by the tour 

stat10'llla· Qt ·tis l'l'1.nt1ng '!ele~h S7$tem now- op-.~crtcl 'bJ tbe Blgnal 

o~tps bet•n WallJ..ingtG••· mwrou,. De\V tor~ q:l'tf • ~-· · · 

2. · A.11 -.ese tapoa ha.ft been prep:ri)4 br - se ot one 

eat Of ktW tapes• lD ~is Oa$e 0#' fourth ot the A u,. tape was allotte4 

as the 1~t fQI' eeoh atAtton!,] 

a. A smali :riumber· ot · t19ogrsp~oa1 9"'Grs mve been found 

in eome Cif· the ID)Ssagej• but q- tbe•·• .e~ ·aot;;al 1I014enta ot tm aa,-•s 

tft.J1$m1a-1on ·••are aio1pheted ._.tlr •-• ~ m.ot•I• '11&N .. ve 119t 'bee~· 1atro4uoe4 to e.d4 41tftou1ti to ttie .~ac>1pJinm•'· ta. oi'd81" ~ be 

asamei- that ao trick. qr U1l1JS11a1 eilOllil&ifmEin t. Wlt.o et.l.te"d into.· an 

't'mllltereet.e~ of'ttoer,.. oal.1e4 1n to ver1fJ this :tact 'b7 _.tual o'baer-

•a ti<cm of tile. methoc1 med as 4.emo11ata tt4 b7 tJ:e 4$o1pheJ'IDBilt • In hie 

pnsepoe-• d the me$S~ being eaat 1ou. 

•• '!his onto• retab$· e:i'Mt copies ot· tbe clpbar tapes tor• 

warded to IU.vel"bank aa 1'811 as tile. ''*'1mnat lingllah tap,.o,. the keU tapes, .an4 the page proot ebeets uaal.11 •4• ·-~ng •• tntiphermeat • 

5. Olle maaage ne so lo- tllat lt riaqttil'ai eiz 1Jteeta to 

prtat lt, heno• part& ot thle mdeage, a.r.- to· be foaal on .Sa separate , ~· encipb~Cl tn acoordanee w1'1 the ex1et1ng 118'1*1 Corps. tre.ff SO 

talih1. Qt ls to be JK>te4 tbat a.U tie 1'1Je8sages e.ro ••lphe1'94 exaotlJ 

aa·preeoribe4 ln the OOP7 ol op,mtljg ft3-a t...-nlshe4 to ,au 'b7 lt1mt-

,.em·nt Oolc>nel J-. o. laubo19le U-pcirl hle ·1.sat v1a-.t ·to tJJs B.lv&rbank 

J.a~atort.e!] al14 that ao attempt; baa been -4• to 41·asa.1ae the cipber 

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0\ REF ID:A414BBM 

·) WAR DEPARTMENT 

'Cffice of the Chief Signal Officel' 

Washington 

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tncu.eaton. so~ .. it ts. to be -.ot'4 --t. til a\1 ht'cll9 wodt 

ot tM SJe•l C.sw wU!l tb» oiplBI- ·•Qbtne .• t'JJa c.,.lpher illd1oaton 

ws.u be ••t la eC'i)tuwei ect• •• • 'o pnvent * .,..~, 

ot •• nm;&~ 111 •i'J'~• alDh I# 'Wl4•fCtto~ to be ~ i..s. 

ZoeqUlNlleat 10 t1ae 8J'&t4D 4ftfll.OJM!d bJ tt.te· 81.,..bank LabGJ'a.toJ'l• 

10r- •• attaolt • 1he btats.ns YeJAtpspb •lll*• · 

&•' lt St io tie "8fttt4t4 t1-t tt.· ..._.. otl!o• t'Dfte aor 

- 4'lat1 wt 1i'b - c ll&WW Mating t!elegr&ph. -·- ani 1 tll ..... up10Jlllttatc • o.ttlelal. inat••• mall9 tt mo•181'J to •. .-. ~J'.18 

.,. ... to ,.oa la 'tJJe· e'lllnal ~ 1.- l•teacl of 1*1.ag 

taalatea ·t.at0 a:tgll•b -.reot•• with G'a:l.tal>le n.listltutt& t1pl'e4 

ife. tJa ·so oaii.ct n-tJ\Ua'* :a1ga1D. One actrantase. h....,, lbiOh 

· n11 e.qoru• le tm te.ot ,,., '*• tJe .wortt 18 4cme by 'lflW oa 

fQne. tnow tn tn.uol'lbi'IB wti.tott. udg'b.t o-.mse oeout- w111 

- •Umltla.WC. / 

·. [y. l ~ ·tm ••• ot thta -ie tant wlll be &ad td 114th -•t 

~ 

1D••fflt. u .s.u ur tu'• 1~_..ue 'tfl4o1- 1011 aa7· 

abo•t tbs. "''._ •·to1t. qbl be .taJea ~ er ta -. 

._fta.~ .. J 

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REF ID:A414B,89 

ist J.m. \..J jom:ho 

O.O.l:i.O., September 11, 1919 - 1.ro l>ireotor, M. 1 • .U. , ,1 . 

· ·~ '111-i I - 6-.J-fo ,:; 1. J:teturned, aok:llaflledgi:rg receipt of cipmr indic·ator code d ';E, 

which is approved, and 'Which will be used in all future work with~1he "V7 

cipher ma.c·hine in question. 

2. .Precaution will be taken to see trat tl:e three lrey alphabets 

for encipbering this code a.re changed as often as the_ key tapes and that 

tho inatructiom :tar the use oJ code ::Ori d out to the letter. 

~::;;;i '~ Squiar, ~~J~~ral, u. • A., "JOhief'~iliJlSl Officer. 

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C· REF ID:A4148Be-:5 \ . '-./ 

~/ ( ~XCl'iiDBUilllD# . . 

M11:...1ARv •NTELL•cae:NcE •••Pt Division 

In replying refer to 

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4131-526 ' · 

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.. WAR DEPARTMENT o.c.P.B.· OFFICE OF THE CHIEF OF STAFF 

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WASHINGTON. 

Septe}Xlber.29 1919. 

Fram: Director of Military Intelligence. 

To: Chief Signal Officer of the Army. 

Subject: American Telephone and Telegraph Cipher.Ma.chine. 

1. I am informed that recently Lieutenant Colonel 

Joseph o. Mauborgne, Signal Corps, of your office, and Major · H. o. Yardley, u. s. Array of the Code and Cipher Section 

of this Division, have been in consultation regarding some 

means of disguising the cipher indicators that )l'r.ttQ.S.di} 

messages enciphered in the A. T. and T·. Cipher Machine. 

A practice of sending these indicators en olair makes it 

·possible under aertai~ oircumstanaea tor the enemy engaged in the solution' of intercepted messages to arrange the 

messages in cycles. All the methods of sulution of this 

cipher lalown to the Military Intelligence Division are 

possible only when messages are placed in correct cycles. 

2. With a view of preventing the solutions obtainable 

as indicated above, enclosed herewith is a proposed A. T. & T. 

Cipher indicator code to be used tor encoding cipher indicators. ~his code is prefaced w1 th f'llll instructions both tor encoding 

cipher indicators and for encipheriJJg the code groups. 

3. It is recorrmiended that this cipher indicator code 

be brought to the attention of Colonel :Mauborgne for his 

consideration with a view, that if approved, in f'llture should 

the A. T. & T. Cipher Machines be taken out of storage and 

used again, the cipher indicators be encoded in the proposed 

A. T. & T. cipher indicator cod~, and that the three alphabets 

for enciphering this code be ob.a.?Jged as often as key tapes.· 

71/ j 

14 CHURCHILL 

Jvk Brigadier General, General Staff. 
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REF ID: A414B&_e,5 

Q:1>n1¥uan:ai1 

. *''''X Division MID 

/ 

JOHN M DUNN 

.) 

From: Director ot Mil1t8J7 Intelligence. 

~o: Ch1et Signal Officer of' the Army. 

Subject: American ~'elephone and 'relegi"aph Cipher Maoh1ne. 

1. .t am inf'ormed that recently Lieutenant Oolonel 

Joseph o. l!auborgne, Signal Corps, of ~our otf'ioe, &nd Major 

H. o~ Yardley; u. s. Arrrra oi th& .Cods and Cipher section ·· 

of this Division, _have been in oons.ultat~on regar.41ng some 

means ot disguising the cipher indiao.~ortt that W.~Q.t:tie , 

messages $nC1phered in the A, T. and ~. Cipher Mach1'11EH 

A praot!Qe of sending th.e•e indicators en ol~ir m~ke$ lt 

possible under oertain oiroumstanoea tor the enemv enaaged in the solution ot intercepted messages to arrange the 

messages in.cycles. All the methods of sulution of this 

cipher lalown to the ?d!lit817 Intelligence Division are 

possible only When messages are plaoed 1n oorreot oyoles. 

2, With a view ot prev&ntblg the solutions obtainable 

as indicated above, enclosed herewith is a proposed A. T. & T. OiphG~- indicator code to be "se4 tor encoding cipher indioators. 

This code is pretaced with f\\11 i:nstr-~ct1ons both tor encoding 

cipher indicators and for enQ1phe1•1ng the ood.8 groups~ 

3. !t ie reoonnendad that this oipher indicator oocle 

be brougilt to the attention of Colonel lfe.uborgne for hie 

consideration with a view, that if approved, in f\lture should 

the A~ T. & T. Clph.O~ Machines be ialten out of storage and 

used again, the cipher indicators be encoded in the proposed 

A. T. & ~. o!phor. indicator oode, and that t-he three alphabets 

tor enoipheri?lg this oode be Changed. a.a often as key tape$ •. 

M CIIUROHILL 

Brigadier General, General Start. 
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REF ID:A4148aB5 

MEMORANOOM FOR CHIEF SIGNAL OFFICER OF THE ARUY. 

Subject: Am.Tel. & Tel. Cipher Machine. 

I ' 

l. The Mil.Int.Divn. ia informed that the cipher 

indicators that precede messages enciphered in the · 

A T & T Cipher Ma.chine, indicating the exact position of the two Cipher Key tapes, are sent an clair. 

2. such a practice makes it possible under certain 

circumstances for the eaemy, engaged in the solution 

of intercepted messages, to arrange the messages in 

cycles. All the methods of solution of this cipher 

known to Mil.Int.Divn, are possible only when messages 

are placed in correct cycles. 

3• Enclosure one, is a p&roposed "A_,T & T Cipher Indicator 

Code" to be used for encoding cipher indicators. Thia 

code is prof aced with full instructions both for encoding cipher indicato'rs and for enciphering the code 

groups. 

4. It is recommended that sho~ld the A T & T Cipher machines 

be tak~n out of ratoraga and used again, the cipher indicators 

be encoded in the enclosed "A T i T Cipher Indicator Code" 

and that the three alphabets for enciphering this code be 

changed as often as key tapes. 

l.A. Churchill. . 
.Q 

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0 REF ID:A4148~'8) ...._,, 

3 East 38th Street, 

New York City. 

Colonel John M. n.inn, 

Chief, Positive Branch, 

' 

Military Intelligence Division. 

Washi~ton, D.G. 

My dear Colonel D.rnn: 

Ref erring to my letter of August 20th to General Churchill, 

telling of my recent visit to Riverbank, and Colonel Maubor9ne's request for a method of disguising the cip~ar indicators of tho A.T. ! 

T. cipher, I encl~se herewith memorandum to the Chief Signal Officer, 

together with a proposed "A T 8: T Cipher Indicator Code" which is I 

pref aced with appropriate inat~~ctiona. 

I respectfully urge that this mB?!lorandum be sent directly 

to the Chief Signal Off icer-.as a recommendation, rather than through 

the Chief' of Staff and the Adjutant General as a positive instruction, 

' . inasmuch as the entire procedure in this cipher is tentative. If it is 

necessary in order to confonn with army practice that the memo. be sent 

thirough the Chief of Staff, I urgently request that I be informed before any action is taken. Will you kindly send me a copy of your 

memorandum as it goes to the Chiof Signal Offic_er. 

Very truly yours, 

M~ H.~~c!'J ~r, 'y f/s1

3 ENCL. • A. 

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REF·. l:Q: ~41488§..5 

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Enziooering 

and Res earoh 

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2 Septemborp l'.H9 

1. J'.cknu.'7leClf,;.::i :receipt of ;y1Jur t-OleQ,::'<·c.n lJU :.::~no0Glf io 

our telegrar:i of August 30t~ and also your le\.;to:? 02 i.iz;-.. rnt 3lo'G11 

which requests tm encii;iherrrent of' all tho DOOc;:l.~12:.i so:nt i:a o:no de.;? 

by all the st2.tions of t.he ~Jigial vorj,'is' illGChino telo[;l~e.p:i~ so;;v-2.co 

now in use in the United :;)tat es. 

2. The idea in sugge:Yt-lns th.st ',7o usa a coo~)let0 111.:;y's 

busiooss :was, firnt of all, to obviate the neaossity o:? \1:dti~1,,,';: c::. 

considero.ble number of fie ti tious me3 sazes; :.:uic1, so co :rnlly~ it ic 

believed that by th is method the E8ss1!:•.t;os \Tl 11 bo ;71ore t;::rp:i.c::.:.1 o::· 

a.otu.al arnzy- work, more concerned 1Tlth wCSc".2.';es .9~'·tc.,i21izlc, to Gl18 

::.10 rvic e of ;;iupply th an to to.c ti ca.l nov €'.'"-en tr:.. 

3. \7o wi. 11, thorefo1~ e, accopt yom_, o ou.d1 t. i O?l ::.':d c:l ~.Jo 

you9 within a fet7 days, e. dcy' s busi:oooo com1 iotir';'~ v.f a'b0u·~ :no 

hundred a.rii fifty rreosages of rep?esent:::,tiv0 lou~;tl1 c;,1u to::t. 

Unfo rtune. tely, as vro ere hal'!diOa9p.cd by 1~::!.Ck. of of' no o io:.·c,'l~ 1:1r3 

will l)e 'll.I!able to translate t,"J.e tapes into \-.11'it·i;,:-.,1 .i:'0'.6YL> !.Jrni;:J:.:.i..1 

we vill ser.ii ~run actual ta,pe::; ruc·,1 ::i.c yo--:;. ',-:-ould !svo t2Jrc'1 o;;"f t>o 

line with yow tapping instrunmntQ lR'":l'kine; the oeGiYUJil1;:;s o::' tL: 

tapes so that that will {;resent no difficw.lty 0 and 1:10 'Jill l.!D,vo ~D 

rely upon yOUI' genercsi ty to IJl"O\Tide tJ1::J ]:X:Jrno1121el to t;y·,:~nslu. I~:) ~:,:-cc 

:9'\lllCheD. c1'.aracters into wd tto:n lette!'O C..:'11 f:lt~t!i:'es. 

4. \'.ii 'G11 rexe'.!'811{)0 to yous S tate;;unt t.h.:.t c:~yOU ~ .. -::iV:10. 

like to have liolonel I'.f1,ubol"'g"D.e' G opinio:u 0'..1 tiJ.e t:iK)o::c~'3i;iua1 a3jDCtD 

of the solution as eluci©ted in :\dd011~: l to th:.J 01°i~;L1~Q ,):;,",:::1o:nt2Uo:u:'1 -

Colonel L.nubo:rgne states tlmt his vhni3 M'!09 in effeot0 boe:.1 /<esm1'2;3~l. in 

tbe letter of tho 29th of '~tt;nst, 1919, siGOOli by 00;1e!c·al u1,':ffi.~ehil1v 

·cthlcn \'18,S P'l.'epared c:,ftor 8. CO!.'Bnlt2.tion bet'.700ln. r·;:,jor YJ.~i':.3.10] C.'o::- ~;o1onol 
REF ID:~~4148Bf8 

- 2 

L:z;;ubor1_~13. lfou u.'iJ.doubt$fily r2-;;e rcolv;:·d. :2. ~~-,_t J?3l'X>T by this tirr:.8 9 we 

no c'.oubt have J)O tad '(;be G:rrce:~')tianB t<::.Ken to 50r.B of yutli' 11.11de:rl;rlr:g 

11re;:i1isos" Fe "1.>3lfevos th;:::t nothins; f'uY·ther naed be add.ed. at tho 

p:resent tiIJ!.7! 9 lind is c:.msi::.;ten'G in his belief tnat no c:atteT ho>:CT 

1E!2.Ch theo!!'eljic2,l 6E.1:,vYwtrati0-n rray be r.i:;."Qsen.ted, yew.· sol12.'tio:;:i u0pe11ds 

u1JDn so '1"87!.~l co1°J.0ect gv.eases c,s ':Jell ;::,s UT,Km so Ea.B.:l otlle17 coincidences 

t~1~J. t tra only sati sfactOZ:';<J arlj'L1stL1En t of tr.£ ant li'e i'JS1tter iv fo~: :7Dn to 

<::Gtn<-:cl ly break sv!:B !:.essD•;-8S ::'.}sGpz:.:rod ~cy tl:e Si~;.rr:i,l Co~ 1J:;~ "11ioilJ v.p 

to ti.12 ;ir0zent ti3Ja, has oove!l' bom: d.on'3. 

5. Yo-1.rr vo:rk? ncr.;avm·~ ~c.B 0 olonel :":.2:v.bo1°gw f!Oints out, lms 

'beol'.). of inestimable v3luG to tha ~1 ig!'.10.1 Cox'ps bec21mc H; ;1.as pointed 

out at l0a:.~t hu sa lieut uoints r.hich 71111 bo tili:e:n ad.tr2nt8.{!,€ of by i11G 

Sigml ~a:-.; "n. rme fil"st is 'l.ihe,t? i.n futare vm:rl1: \7ith this mt'W.J1:l.nG9 cit1he:r 

inrlic o;to:rs should 9e codode Socontll;7? your develo~;r:1mt of the overlcp·_pins 

featui~e ;,:oor:ml tiug fJ:'OD the u.ce o::: 'i::.oy t~es ;t2<.:rin:; 2' total :nur:De:& of 

c~l<:.racteX'c r;,1®. '(,j1gt the m.~<foer on om tapB ;;:s:.y be divided uithout 

r22::-,inder into the m:uJ1lo? 011 tho otl1G? t Bl'G' o:;;" tl1.'.1t fue nU<.11bs~ on 

botl2 t8p8s :im.s be CiiviocC: by thz· samo m:rrr.J)e:r, sill prove o:? d:3cided 

2.dv8D.t2.,'}3 iu the sclGcti on of th<i 1Gimt~1 of l:B~l tc-,pe s. These tT.70 

fcatu;res CJ,lonB, r::igm0 dJ.oos of oihor f'e;;"tures ·cilich -r:ay ::;"..Gvelo~) as 

yom: ".'O~r •1roX?esses. 9 lea.Ve l>rnveC. of ini:::10nse vclt'!e t:.i the Si;,;ml Cm;opc 

W'.ld I t2ico tb is oce::;.si on to express r:iy ti12,111ru x:;.ot; only fO'i' the 

0Jq_10Dd'i, tP.re of til'9r, lE~ Ol' f.l.nd rnoYie~r ',7hiCil you h~.ve r1:,,do en thi~ 

Citihc:;~~ b1-lc ;:;,lso Oil tfl...e Gt 1131' cri pht:Tc: SYl.1J"::1 ttod to :/OU. i:n t¥10 P<"'l.E t 

by t113 Si;:;1:cl Golf"lls. lt in tow tll'V.Stcd cho,t you\7ill rontinue to givo 

to t.h::; :3:l~';lli!l GoJ:~:)s T\i1:e:rb2.~1k !ii hrn:.;,rti0s'G co-o::.12:R>,'i;io11 antl you r.~y 

!JO ?rSSU1'<'1Cl. t!'Dt yov? e1:'.os:ts d 11 c.l-::'3YG 1)8 l'(::)Cip!.'OCcted.. 

6" e ex) sc t 'co 1:.J e 2 bl a ·i:D fa..r;:J.i &l yow. foo :GBS s<..'.:::;es you 

lle:;ir'e i::J.e'C.in (.\ ·;·e~;).l: enc trust t!Et )D12 nil!, co:cc0i'.it:<.',.te your cf:?o:rts 

0~1 ·L~'lB ')j._.,r:.Gt5-.c:._~l ":-;)-,:~;: o:? c1eci}):i"1m~in::; tl1crr:. 

r.:reo';..'S8 o. S<rJ.ie:C.'11 

z:ejoJ." Generol ~ 

Ghi0:f :JiG11S1 Off'iCCE'·