- . ..._ ••• ,.,,bl. 

MEMO ROUTING SLIP ,.. • , SAPPROY ALS, 

I CONCURRENCES. OR SIMILAR ACTIONS 

1 NAME OR TITLE INITIALS CIRCULATE 

Dr. Kull back - ORGANIZATION AND LOCATION DATE COORDINATION 

AFSA-03A 

2 FILE 

- INFORMATION 

- 3 NECESSARY 

ACTION 

- NarE AND RETURN 

4 SEE ME 

- SIGNATURE 

REMARKS 

Herewith some old papers which may be of interest 

and use in AFSA-03 files, for historical purposes. 

One set of papers (Encl 1) deals with an early t)pe 

of coincidence machine. The other paper (Encl 2 

deals with a proposed machine for locating 

idiomorphs and isomorphs. I would like to know 

if any machine for these latter purposes was ever 

built -- aside from any modifications in IBM to 

do the same kind of job. 

FROM NAME OR TITLE <"IA.)~ 

ORGANIZATl"N AND LOCATION 

AFSA-14 

NM E FORM NO 9 5 Replaces DA AGO Form 895, I OCT 48 1 Apr 48, which may bo UIK'd. 

eclassified and a roved for release b NSA on 11-18-2013 

DATE 

16 Aui; 5Q 

TELEPHONE 

1.. ')I) 

06-Ul--48487-8 GPO 

ursuant to E. 0. 1352 
From To 

1. SIS WP&T 1. Under date of April 16, 1937, there was 

forwarded a sketch and brief description of a 

machine which has been called a Cryptanalytic 

Coincidence Counter. This machine would be very useful not only in Signal Intelligence Section, 

but also in the Signal Intelligence School. It 

would accomplish, automatically, certain operations and calculations at a great saving in time and 

labor. It also would afford the basis for further 

extension of ideas regarding the construction of 

electrical and mechanical aids in cryptanalysis which is becoming a field of very considerable 

importance. 

2. The principal pieces of apparatus required for the construction of the machine are 

printing telegram transmitters of the type known 

as Western Electric 1-B Multiplex. It is understood that a certain number of these transmitters 

may be obtained from the Hawthorne Plant of 

the Western Electric Company at Chicago at a price of 

$25.00 each. It is desired th.at six of these be 

obtained if funds are available therefor. 

COPY 

H.G.M. 

W.F.F. 

6-5-37 
REF ID:A105026 

Scvt tc:. • • - I 

8 

ocs1ao. w.P.M!. 1'1v. •pr1l 17. 1937 ... To The Oht•t Bicmtl otric•i: 

l. tt io r.come~ed th~.t th11 mlt.ter be reterrec! to th• Stpal 

Patent Board tor suit4bls action, 

------

. --·~. ··- -·-------------~ ·------~· --- ---- ___ -,_~ ____ ,___ _ 
REF ID :A105026· SIS~ 

BECREii 

WAR DEPARTMENT 

OFFICE OF THE CHIEF SIGNAL OFFICER 8 

WASHINGTON 

April 16,. 19.37 

MEMORANDUM FORt War Plans and Training Division. 

l. .A.ccompa:ey'ing this memorandum is a aketeh and briet 

description or an invention or a machine which I have called 

•A Cryptana~tia Coincidence Counter" and which would be e.x:-

tremely useful 1n our work. 

2. ~lso accompa.J:\Ying this memorandum 1~ a descTiption ot 

au invention or a machine which I have called nA Cryptsnalytle 

Id10.orph and Isomor.?h Locator". This. m!'lchine is a good deal 

more complicated than the coincidence counter, but is not 

thought to be impractical. It would also be Vffr¥ uuetul in 

our work. 

3. It is recommended that both inventions be submitted 

to the Signal Patent Board for such action as le deemed suitable. 

In rq opinion both inventions should ba placed in the isecret 

category, at lee.st ror the present. 

William F. Friedman. 

Enclosures. 

SEORET 

·; 

' , 
• REF ID:A105026 • ROl'l'DJG AND WORK SHEET ---~-------·-----------

Number 

each From Tn. 

Action 

1 SIS WP&f l. Under date of April 16, 1937, there waa 

forwarded a sketch and briat deecr1pt1on ot a 

maahine which has been aalled a Cr.yptanaJ.,tia 

Coincidence Counter. This machine would be wry 

useful not only in Signal Intelligence Seotion, 

but also in the Signal Intelligence Sohool. It 

would a.ocompl1ab, automatically, certain operatioms 

and calculat1on1 at a great aaving in time and 

labor. It also would afford the basia for turther 

extension ot 1dea1 regarding th• aonatruct1on ot 

electr1oal and meoh~cal aid• in OL"JPtan&lyei• . which is becoming a tield of vecy oons1derable 

Initals 

and 

date 

· • • · · • · · :. · · · · · · · · · · · · · · · • · · :f:mportanoe·.-· · · • · • · · • · · · · · · · · · · · · · • · · · · · · · · · · · · · · · · · • · · · · • · • • · · · · · · · · · · · · · · · · · · · · · · 

2. The prinoipal pieces of app&·atus required tor the construction or the machine are 

printing telegram tr&nsmittera or the type known 

a1 Wastern Eleotrio 1-3 Illultiplox. It is understood that a certain number ot these tran1m1tters 

may be obtained trom the Hawthorne Plant of tb.e 

Western Eleot~io ComparJ1 at Ohioago at a price of 

t25.oo eaoh. It is desired that· six or these be 

obtained it tunds are available there.f'or. 

H.G.11. 

w.r .r. 

.. . . .. . .. ... . .. .. . . . . .. . . .. . . .. . .. .. .. . .. . .. .. . . . .. . .. .. . . .. . .. . . . . .. . . . .. . . . . . .. . . .. . .. .. .. . .. . . . . . . . . . . .. .. .. . ... . . .. .. .. . .. .. . . . . . .. . . .. .. ....................... .. 

....., .., . > I '1 I -

,. .. - ........... .-,r·,;ooi.. • • • • .. • • .. • • .. • • • • • •• ""........................................... • • . .. • • • .. • .. .. • .. • .. .. • • .. • .. • • • • • • • • "'. - ••••• "' ..... .. 

.Sheet No;._ __ _ 

' 
.. 

REF ID:A105026 ··.;;. 

NOTES OU SETJ'IlfG UP AND OPERATING 'll1E~ErJCE MA.CHINE 

The attached dia~rsm eives the location of the tape transmitters 

with respect.to the row of jacks to which they are connected. The 

.jacks are numbered from the left hand side of the panel. The first 

5 of each roVl are connected to the back contacts of the tape transmitter, the second 5 are connected to the fingers, tho third 5 are 

connected to the front contacts, and the 16th and l?th are connected 

to the stepping magnets. The connections for the remaining eee.te:e'b~ Jo-c-6 

are as shovm on the diagram. These remaining contacts are simply to 

be used :f'o.r convenience in m.Aking connections and have no rolation at 

all with the transmitters. 

The machine operates best when the s tapping magnets of' two 

transmitters are connected in series. Four will not operate satisfactorily if connected in series, and if' Rll are connected in parallel 

too much sparking of' the cor.unutator brush results. All 10 segments of 

the coI1D11utator should not be used at a speed of around 500 characters 

per minute. Best results were obtained by connecting segments 1,2 and 

3 to energize the stepping magnets, and segments 6,7 and 8 to energize 

the counters in the CGJll.paring circuits. The counter giving the total 

number of letters counted is connected in parallel with the stepping 

magnets. 

If only two transmitters are used a ~-MF condenser should be 

connected in the s tc:Jping mae.,net circuit to suppress the sparks. A¢ne 

mego)i resistor connected across this condenser seemed to work fairly 

satisfactorily.When A.11 four transmitters are used,the 3 3-UF's are 

connected in series in place of' tl.e -~-UF used in the case of only 

two transmitters. 
l 

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REF ID:A105026 

Dtt1cription or the Qe~erLl Prinolpl•1 ot •U Invention 

of a •achin• tor Looatins Ic!iomorpbe n1~ Xaomorphs :bl 

Ceypt,e n,_ l.)'•111 

l. Th• •x)1'l)r1ena•d 017ptanal.11t v•r)' tr•quentlT b•s oocaeion to Ufa 

th• •probc~l• wor~ .. tbod9 t th't 1•, ho ~••UlltB the pr•!enoe or • word in 

th• text an1 trie1 to t1n~ it 'b7 ono •~~r.ut or ~notber, thw word tor 'llhiob 

b.• is n•r.rob1;ns uau•.\ll;,y contninr.t IJGTor~l n~-:t•4 letter• tho 1dent1t1oa 

al:ld poa1t1on• ot •b.1ch !apart to th• worJ a ob&racter1at1o or p•ouli~r 

•pattern• or •t"oriaula"• Buch •ords •re wx·111od it110112misl.• For •X.lllllpl•, 

th• wo:rde BA!'TALlOl1 DIVI8l011 and IP.TlLl.l.."!.? ar• id10J10rPb.ic, a!l1 •tich hMt 

a cU.at1uot1 ve tormul' ot coapo•l t.1on. The tol'ul.e. tor th• •ord !A't'TALIOll 

i• repr•1•ntftbl• b7 • ~u•noe ot 4~b1tr-r1].y-a•1i1n•d dl&ita eti-n~in& !or 

th• ditt•r•nt a~ th• ai•il~r letter•; •• shown h•r•~it.h1 

B A ! t .A L I 0 I 

12,)24567 

ln other words, th• 1diomorpb in •ood•dff tn th• .. a~• ooamonl7 •,POkon or 

iJ& 001ll19~t:tou •1th tb.o UH or to.'bulat.1ng """eM.nlfr,1 ope%'at10:01. 

2. Suppoe• the or,pt~nPly#t aU&t~cte the preaence of the word BAT1'ALtOI 

in a ..... ,.. R!V12!1 •1tabl1ah•d th• to:ra;ulo tor the wo~d, b• ioa• throuch 

the t•xt, 'bea;innina with the f'ir-at l•tttr and 1lldil'l.I the rorsula .ag•inet th.a 

text otie 1t•r> at a. time, un.tU. he tln.'.fe Ii plac• Where th• f'oraul• for .a so- qu~na• ot nine letters in th• t•xt is •~tobe~ bf or co1nc1d•! with th• toraula 

l 2 ) 3 2 4 S 6 7 (. B~.T't.lLIOI). Ia t.b1a p:roce111 the or,rpt&.nal11t mWlt oith•r 

1n.l\1Q3t• on plJpax-, or eee with h1• •ind'• •1•, thO" toxtU.'ll tonulJ\ th".?.t 11 at 

th• .moment. in 3uxtapot1t1on "1th tb.• ro:r•uta of tho word tor whioh h• 11 

H&robtn.c. 

'· Apin, th• ceyptsn!'l.yst Kf net ha'V$ a detintt.e word in aind tor which 

b• ia ••~robins, but is ai•pl.7 de.,iroue ot loo~ting t•o fo:naul.ae 'llhieh are 

ideut!oa.1 and. wh1ch ar• tech.nic!!-111 c~lled i12111or:ih1. In thi• cAe.e, h• ••- tabl1zhea a oonti~uou$l1 ohnl1(1ng ueri•s ot tor=1U.~e, b•ainnina with th• tir1t 

l•tter or tba t•xt. and tsate •r.oh or tbeaa •csinat th• r•~~1n1111 text of th• 

a• •eHnc• o:r ap1~1t the te~t ot another ••••.r.c•• For OX!,a~le, ha •Y 

•tart with th• t1Tat ten letters ot tha m•a•'I• ~n.1 note the formul~ for these 

ten lett•r•• Be thon ~Prli•• thi1 firs~ ton1ule to ~:m>tb•r p~rt ot tbe text, 

bepnnlng •t e. ci..-en po1nt. .-nd •li~ing; th• for11ul.a a1ainat tb11 tH:t one st•p 

at a time to aee ir be fin~~ ~aotber ••~uenoe with an id•nttcql rormul"• .If 

aot, he tt1rte -1th th• eecon~ lett&r ot th• •e~tig6, not•• tho toriaul~ tor 

a eectue:net ot t.•n l•tter•, ~11-:l .re.,e!:.ta the eet1r~h. fh•n he •ncoul'J.ter• a 

toraulA whi~h co1no1d•• •ith tbe ono h• h~• ••t up, ho h~D to'l.U'l'! a oee• ot 

1eo:iorph11a. 'fb• two iaomor)be iu7 or •~Y not corre1Pon·1 to th• H•• pl"i:utext. word, For •Xkajlle, tba threo word• l',\l\fi,UfJ', LltT!RS, and llIBSIOH h!lve 

SEeRET 

• 

- . . ·- -: --·.:.-. .:-:-: - :---·--··-::.--::---:-::-----.--:---:---=--=--:-.::....-=......-:-::-..: .......... _.,,. •• ~----. --· 
Mi!l,.,_,--· .. •;·r "': REF ID:A105026 ------·------·~ .... ~.!f---· --~ 

SEOR:: .. 'J 

identioql £ora'Ulae «!Jd •r• taoaorpb1c. Xn eosrch1n& tor 1eo$Or:?ba, it th• 

cipbar t•xt abould oontt-in all ~hreo ot tb•&• •o~da enci?b•r•4 fJOnoclpb~­

betianl.17, th• 017;tal1!l1st would not know wh•ther t.h• iao1110~ph• he fin~• 

in th• ••••':ge r•;>r•ae.t thr•• oocun1t11(Htt ot t.h• •r.•• word, or t•o OC;lW"'-

r•nc•a o.r on• word plue A di!fe~•nt •ord «1th the ,.,._ ro:rmul~, or • •1n&l• 

ocourr•i:ie• ot tbre• ~U'.t•r•nt worda. 'l'heea altern!!ltivet would b• 4ettJTained 

latctr., bT t~i!l•t" e.n~qa1a., lt th• aoaont, thet btport='.nt. taot i• th~t. he 

bee lo=ated oa~•• ot iao1&0r;rbi1•• 

4. th• prasont •k~nd• aetbod• ot laoatina l~1o•orph1 and 11o»orpbr 

•r• 't'ery tedioue, alo~, and •ubj•o.t. to am·1.n er-ror. Au.t.oa~tio M'lhinea 

for loc.iti.Q& the• would be quit.• uaef'ul, l!n(l it. is th• pm""po•• Q/ tb1• is.tYtntlo~ to p~ovtd• auo~ Jlll.Chin&a rind to detcribe the •eibo1 ot their ~e. 

1~a1c~1i,, the 1DY•nt1o~ .. plo1a th• coapa~1Jon circuit• \lied in the •ooincl4eno• countera de1cribed in •noth•~ pa.per~ in ao•binatior.i with ad41t!on~l 

meeh~n11a3 to b• d•earibed. 

'· Tho text 1n wbioh idio•orphic or 11omor~bie ae~~ncee ~r• to b• 

loot.ted 1e pr•p&r•d 1n the ro1·ni ot pttrtorti"ted Jb,uit!ot t~pea.. Sever&.l eopi•• 

ot th• toxt tepee *:r• prep·~red, the nucber- d•pelldtnr u,".JOn. the l•qt.b. ot the 

1.-q,u•ncea tor •b.ich •· p.ven uchine 1a coruatru.::.t,,1. l'.aohtnon ror locatin& 

6,. "!., 8, ..... l•tter eei;uences •~1 "bo conetruo.t•d• Thie desorl;>t1oo tdll 

de.ul w.it!l ma-chine• ro:r loc~·tins ••r.u•nc•e u, to th• l,eqt.li of' ten l•tt.r•• 

In 1•t20r~l, th• ~utom,tic locAto~ 10•• th~o~ ex•ctl..1 the e&.me atepa a• 

dot• the hur~un OP4f?'iltOr at pr•a•nt, but at a nob gr•~.ter 1pr1ed, .!ltd with.out 

oY•rlook1nc paaslble pl.oc•• •h•r• co~t~ror 1e~uonc•a m-.7 ax11t. 

I. !be idio•oryh loc~tor. 

6,. rt.rat to 'b• deoodbed -1u be tb• i41omol"'ph lool!'l.tpi".. Let. ti• •••um.a· 

th'!lt we tte ••a.rchin.& tor th• word IAtTAt.tOMS, tb• s>X"•••ne• ot •bieh 18 IUI ..... 

p1ottd in th• tollo~1'Q4t t•xt1 

.. 

. t 

1. !'b.• macbi~o conl1ata pr1a~ri11· o! 10 Sau1ot t~pe tr•:na~itt•r•• 

•acb beinc wit•d £or eoap•~isoc pur.PO•••t in a atntt~r •1•1l~r to th~t •mplo7ed in th• Ro~1Do1dence ooua.ter". Xn this oa•e, 10 tape ocp1•• or the 

••••l'!I• Ar• prep~r•d e<ua th••• tG.pttt •:-• plao•!S in t.htt t.r~·ntr•1 tt•ra to th~t ., th• eucoensiv• •t~:rt1n.r points on th• euco•e1iv• tl"'~n~•1ttora corraepon.~ to 

th• auoc•aai v• l•t.t•r• 1, 't 1 D1 •, • • • ot the ••tt0.1•. 

I. Olol1n1 • atM.rt1.na ••it.ch, th• tirat letter ot th• sesar:rp" A11 in 

t.r-r.ns•1tter l 1e te1tttd auee•ssh·ei, t.C!".inat tb• ne:w:t 9 1-tt•i"'• ot ·L'b• •••- •~&•, in tr~n,mltt•ra 2, 3* 4, ~. 6* 7, s, 9 •Dd 10. 41'hie 1• doJle by m&~n~ 

ot A aotor-drivan rotery multi~le awitcht or otller .. l!.l.ns, sbio.~ tuac••&1"9]Jf' 

' \ 

\ 

' 

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··-·· - - ---------------------------------- REF ID:A105026 

_,_ SZORB'Ji' 

c:oxmecstt the wbol• ••t ot ooap~rieon contacts or t.rs-nmtttar 1 •1th t.boa• 

of tr~nsl!dtt•r• 2 to 10, in turn. Th• oomJ)-;lrieon oirou1t1 in th1• G$e• 

aerel.J eer'f't to o~r6to euporvlaory hie!'t-a;ia1d tal.aphon• r•l~1• to d~i~• 

a ••~1•~ ot lG rot~tabt• 1niic3tor wh .. l•, th• per1ph•r1•s ot •hich are 

41"'1.d•'l up 1nto 10 •~U'\l aapenta, numb•r•d troa l to 10. (Thie oorr•a ... poni1a to the •oodina• tuno~ion r•f•rr•d to in P~r. l.) At the •t~rt ~11 

1ndio~to~ wb••l• ~r• at t.b.•1r ~•••t or 1D1t1~l poe1tioo, •ith eoa-ent l sho~1~g throuth a •1ndow or •li&n•1 at • bench aP.rk. In~icat.or •h••l 

uW!lb·i"r l io alw11)'0 s•t t.o poa1t1ou l .:a~ Med nt>t. abr-ups it 1tt1.7 in tact 

be • •d~• wheel. It no co1nc1dena• 1a enooun.t•r•d when trtneridtter l 

ia ooBp~rlftd with t~~nsaitter 2, 1n~1o~tor whe•l 2 a4v~nc•a to ••a-:ent 21 

lik:e.1ae_, wh•tt t.r.-n&•itt.er 1 ia coapr.r•~ wit.)\ tr:!tit•itt.er• :t, J. 1 ' 1 ... _ 

and no co1nc1denoe ia •neounter•d in ellj oi1e, in11oator wheol• '• 4, s. 

••• tdv~nce ~~ ••cm&nt 2. Jut if & oo1ne1d•no• 11 encountered at a07 co•· 

pri.1 .. ison, tb• izri1tJa.tor wheol &11ooiat.ed •ith the t.t~n1aitter b•ina -OOl!lpe.r•d 

•t thli·t soaHtnt 1r not ~raitted to a4Tanco an7 t\lt't.htJr a.Dd ~Jnf>ina in t.h1a 

po1:tt.1on. Tb• arrtilll•itent for thie 1tApp1n1 •"'1 b• b-1 11e~n9 ot • continucual.7 aot1ng ratchet and p1url tor etch Yb.eel r;nd onl7 when there 11 coino1-

d•noe 1& t.he pawl witbdrawc !iSJ.d loek•·i iuto 1n.-'1ct.iv• ?OP-1t.io:a.. J'or ezt'trApl&,. 

tak• the first 10 latter• ot th• 1lluotr~t1v• ••••~g•i 

l 2 3 .4 !S 6 7 4 9 10 

i P n If II G 1 A ! 1 

Attor tr~DSJl1tter l (aat to A) ha• beon. to&tod 11&1nat the r•tt or the tr~ns•1tters, th• lndic!!.tor W'heelt are •t the toll.ow1nc poa1t1onH 

l~~1c~tor •~tel - l 2 ) 4 ~ 6 7 8 9 lo 

!ext - ! l .. !.I I 9 l ,A A l . htti:oa: of trbee1 - l 2 2 2 2 2 2 l l 2 

Thia correaponde •1th the r•peated l•tt•r A 1n po1itiona l, B, and 9 ia th• 

aeQuenc• A P n I I G P A 1 r~ In~1cetor wheels 9 N:ld 9 will now ate7 et 

po1ition l. 

tran111ttter 2 i• no• t•ated ~lhinst the rea.11n1ng trc~ennitt•rn• in t\l?'n. 

Since tho letter P do•s not reapp;~r in t~ eo~'Uflnoe, t~• in~lootor wbe~la 

,, 4t '' 6, 7,. •nd 10 adv~nce on• •top. the f'ora.ul1 11 thens 

In~1cator 'lfboel - l 2 ' 4 ' 6 7 3 9 10 

'l'ext - t r n •• q Z: . .l t .. f'. 

ht.tin& ot wheel. - 1 2 -' ) ' ' ) l ' 

TrantMitte~ ) i• ~o~ t•~t•d a1ainat ~he ~amiinint trenaa1tt•r•~ i1' turn. 

81nc• the letter D do•• ti<'t r•cur~ tho 1n11Qa~or wheal• 4, '' 6, 7~ and 10 

e.dv:1>nce on• e;t1p. Tbe 1uec•11iT• fortaull\e set u9 on the 1n11ontor f'heel• •• 

the auec•e~i~• tr•n~mitt•r• are t•ated in turn hf•1n•t t~• r•Zllining one1 •r• 

e.1 tollcr1Y11 
-------- -----

REF ID:A105026 

l11'1.lo·1 tor -.heel 

'ttixt 

l

A 11- a.-ain•\ r&oniutng T1 ei 

P T~ age1net r•~aining T'~i 

D 13 •Ct.inst nin!iining f' iu 

M !4 ai~inat rea~inins; ft11 

(G T6 a&aiaat rer.u.!ni'Qi T'~• 

(1 'f7 aeainet t'lllA<~iatna T'~t 

SEORB'lf 

!he fol'!llul~ tor the word B~TT.H,IO!CS ie D i T T .\ L I O !l 5 

12J3Z4,678 

~hile th~t r•sult!ns !rOll th• t•at ia l ~ 3 4 4 5 6 l l 6. Ther•foro, 

th• neatip doetJ not t:t:1rt .. 1th thia ttord. 

9.. 'rno tl!lopee in 1.'ll t.ran11\itt1rra ar• Ad.Vi.\noed on& 1to;_:i eu1d the ttn\i• 

proceduro iis followed as be!oro, now teaUne: th• 2'd, Jtl 1 4 .. llth let.tors 

of th$ .m•tfzwces. Wh•n th• te&t. bogiao w-1th the 6th lett~:r: ot th'1 llO&il1ts,;C9t 

tho tollo~ine ~·~uonoe Qf uovs•snt' ot indie~tor ..-h.~ela ooo\U"ta 

Indicti.t.or wh•el 

'hxt 

.a) r1 ~~A1net ~•mnining T•ai 

1 t2 al61net r•m~tning T's• 

A TJ •ca1n~t r••~ininf T'4i 

Y T6 $&&1.n•t rertllinine T• H 

Q 1:7 •g~inet rea&ini~ T•et 

Z TS •£~inst rtm!.1ntna T' 1u 

I 19 against ram4in!n1 t'a• 

l 2 3 4 ~ 6 7 8 9 10 

Q t A}· .. 'f..:J. ' ~ X ! 

l 2 2 2 2 2 2 ~ 2 2 

1 2 ' .3 2 l .3 3 ' ' 12)3244444 

1 2 3 3 2 l ' ~ s s 

l 2 ,; ' 2 4 s 6 6 6 

l.2J)2.4!S677 

123)24S67S 

T'.a• final tor:aullt corr•sPQnds with that o! BA1'TAL10lfS e.n1 httnc• th• word BATTALIONS~ •xi"t ~t thi• point in th• m~f~rg•. 

10.. It rlll bit notoi th•it the o~er~tor rust etop att£r e~ch teat to 

co11p.'ire th.• £inal f'or=ul~ with that of th• •ord being eoll£ht~ But by goin& 

on& at•p ru.rth•r# th& eppn-ratus atty b• oon5tructod ao •• to eltainw.t• thle 

aource or deley .. 

ll. Let tho p«1.ripb~cy of each 1n1ieatcr wheel b• provid.•d •ith projectitsi p:in9 Pf'rmuted in aecord~no• with t•n difi•r$nt oombin~tionn or th• 

Baudot code and let 1Jtoft& pins op~rat• tho eer1•$ or eopteats ot a •et ot ooa~i:iaon 01.rcui ta \ $aoh •a in Com~ertor Tfμo M-1; ~-1'1} tor tosti~ th• 

i~ll3'~ tq£m~;t !n!jlt it§ ~~~i rB§·k~a 1s~~lij~Atm.ll1ltfwitl~ip~~1a Hdfadf'Ill!R•i-ftti tHi hio-ral~pfBi ~sn~!at\~F !~& t~pe t:-c.ns111tt•r• •r• 

aotUAtcd $Q1 $ll th• tt.p&a at•p!>#d for~a.r-d ti•ulten6cual.7 wh•nev6r the final 

tol."'llull'i doatt cot coinoide with that tt(lt up on th• t•at !l•.etJo. Thun, one• 

•tartod on tt. H!Uleg•,. thtt te$ting would oontinw without a 1t<Jp until e1tbor 

s. coincidena• botweau ~ tin"ll forr~lJ.l.;i ~tl'.l 11. test fotmul:ti 14 encount1.trtH.1 or 

•l•• tbu en.1 or th• Mas:-.p 1• rer.ehtd. 

··~ 

-
- ·-------· REF ID:A105026 

SEORB'I 

-' -

12. In oper.:t1Dg th• 1d1omor.;>h locator 1t 11 nac•aitll:ey to 8ot up • 

rormule on n t•at rr~••, a1~1uat ~1cb suco•••i"re t1n~l £or~ul~• ar• ttt•t•d 

1n t,urn. It th• wox·d ao~t ror 1& not. in th• meae~1•,, a new teat tot'lflUl~ 

has to b• 80t Up on the test r.raae and tb11 woulil be done b7 h•:nl\. But in 

•oarcb.1nt tor 11f.o•or;>bs •• do noi; hove bll1 apoo1f1c toruiula tn :si.ndJ w 

take a:n)' a~uence ot letters in the te7.t en~ co~pDr• it with •i•ilkl"·l•nath. 

114Ki_UOnco1t in the •~•e taxt t.o se• it tn•1 era 1.eomot~1o. 

l,. Su,vpo1110 th .. t. thwro i;rc; two aeta ot tb,?4t trm:it."a1tt•r•1 e1:oh opara.tj,ng e. Stt'l. of inffic!ltor 1l'btteln rttd let one .. t

1 herainf'ftei- <mlled the ~ .l!1 or tra.nsllittera, b• uaed aerely to eat-bl eh tel!it :tor11ula.o on th• test. 

tra•e,; t.hC1tf1 toJ."•:tult:e ac,r1'et!:,p-0n~ine to s.ni., heins: e•t up b# aotu~~l 1H•~uenceu 

in the meas~ go iti:::8lt., Let tho other rs~t or tr"nomitt•1·is, here1n.·.rto:r crllod 

th• !ff'le.t1m,, ~•Ji ot tr1ms1dtter11 be uM~ as th• source ot suoceedve t1n11l 

tormulfe to b• tested ot,r1n$t tho fornulr ae.t up on the test set ot tX"nnla1tt.Gra. Le't. the tapee on the •sB~i• nt bo circular, b)' joini.UI tirat itX.ld 

laa.t oharaotere. Let tti.• a.tt:·ne:••nt bo •ueb tbr .. t when • teat torD.tula 1a 

wet up by the *••t eot ot tran~aittera it at&)• th•r• until tho •nt1re me1-

1ae• hba baen teeted acainat 1t1 it no coinoideno• h~• been e~cow:iterad, 

th•n & nett t.e$t ror•uh .1a oot up b)' t-l:u~ toet a•t or tranamitt•r• b7 a4voncini the t.6JJel 1n thete trf:n&r.11"..t•rl\1 t..nd the procefl.& r•1a~ated, the tepee- iu 

the 1teaa~go eat ot trrnaa1ttera botns back again at their initial potitiona. 

lben ts. oo1nc1dence ooeur11 bot•Gon e. torcul" on the test !rM.ie ~u1d a. rin.-.l tormul~ set U? by tbe 5on~~eo ~et ot tr~ns•ittora 1 a oircuit i• completed 

which lighte a X"ed lt-mp en'! aito?ts ell tr;"-!lG~i tt•:ra. 

We~bincton, n, a. 

April l.4, 19:;7 

lltLXtK 'I. F"nIZDKAff, 

Prinoip•l Cr1pt•tv!l1~t, 

Si~l Intellig•ne• Section, 

War Pltn6 ~nd Training D1viJiou, 

Office ct the Chier Signr-l Otfioer. 

Th• tor•foii!C invention wnt de1cribed to ut ia February, 1937 by 

11•. :Frie~JIUJnt 

-.-.-r "''"'llW kr;ucf ........ ,..'*.~ .• l II 111 • ••1111 I I 
REF ID:A105026 

SEORETINVF.:NTIOM OF J. CI<I'P'l'LNALl"TIC OO!NCIDE!ICE COUN'l'E.R 

1. In c1·ypti:.n~ 11ais it 1.e: often necessE.r) to teat t.to or more s•~uencea or cip~er letters to ~&e~rtain ~heth~r they 6re enciphered 

in the E!.'..J!1& cr.>cit.:>trt::.phic i;ubetitution period. One matbo£l ot teisting 

euch se~uenees is to su;;>Grim~ora thea, count for each colu...'"'ln the number 

ot co1ncidencee (1.e-, c~sea ot identity) bet~een letter~, totnl the 

coincifencei:: for the entire super1Rlpoe1tion, e.nrl oei.lcul~t& the tot.:s.l 

numbE::t· tbeorotic·~lly t.o be expected. If the observed nll!nber tills st~.tittict.ll:;r w11..h1n the limite or the theoretietl exa;i&ctancy, t.be 

supbri11poaed f·tt;,uEncec mRy be re;irc!e1. SP belonginc to the a;~.,.se ceypto;;re.ph1o substitution iJOrlod, 

2. "Hen~~ .rcethodr,11 of count.int the nu.mbor ot coincidences are slow, 

to<!icne:, nn" aubject. to error clu~ to e.ye e.nrt br.e.in fa.ti&U~ .r..tter a. few . minute:: y,ork.. Tho preecnt inv~nt1on prim~·riq p:rovideE a SJ-Stem and a 

mechanism for autoMatic~lly observiJli ~nd tot~l1zing aoinc1dencea. It 

m.&.-, be &1!1plo)1£.t! fer othcir crn•tt:~lytic operLtions, as will be a•t to:rth 

eubsequer..tly. 

),. lle.sict:llJ, the mechsn1S!'!\ compriceL u. r.eri4U of tepe tre.nemitwrs 

ot th~ etan~~rd B~ucot or 5-unit-code tyi.ia, but wired in a £pec1al l!E.'.nner 

£or aeries-circuit, em?loyl.i.f;nt, prefernbly throllib tbe int$rmcdiuy oi' a 

plut; e.n1 Jack ewitchboe.rd e1!1ploying flerlblo con:!uctore, "'nd one or more 

electricll counters controllsd b)' the trti.nsmitit&re. The accomp~nying 

eketch1 Fi1. 11 ebow~ three tr~ner.ittcre, l, ~~ ~. ~rrenged in thi~ m~nner~ 

with certz:in con'.iuctor• ,..ired per1:2nently to switobbo.ttr:1, 4, which ia 

shown as di?ited up into severG.1. panels, 5t 6, 7. The tr~nsmitterp are 

provided with.the us~l t~pe-r.tepp1ng magnets, 8, 9• lo, to ..mich power 

1s delivered intermittently through a ca.m ewitch, 11,. driven by a motor 

or ot!'.ler meehenisro., 20,. ao as to as.use the t~.pes in the tr:.ns111.ttera t.o 11tep 

.font.rd s,.nebronously •t about 120 ateps per 11inute-. !neee t~.pes bae.r 

aet~ ot pe~ror~tion1 in the Baud.at code corres~on~ing to letter~ of the alph~bet, nil' the sec;uonce. or eets on et:.ab. te.pG corrasponda to th• Eequences ot lettero subjected to the count for coinoidencos~ t..~e tepee beine 

pl.heed in the lrane:aitte:1·a t.t the proper init.ic.l points of super1rr..posit1on 

tor the count. For e:r..ample, suplJOGe there bo e. mer:s.ega or ;2000 lf.lttero 

and 1 t ii:.: deeirtie'. to count tl':le number of coincidei..ces bety,·een letters 1 to 

l'JOO and 1001 to 2000. Vuplioate tepe~ 0£ the. meeP.~ge are m~~e end one ot 

these tc.pes is pLced in tr...nr.mitter l with letter nuuber 1 e.t the initial 

position (&bove the tr,:neir.:!.tter pineh the other t?>pe is pl!>.ced in·tr.r-neznitter 2 with letter nUli~bcr 1001 i..t the in1t:h.l po~ition. Flexible conductors r..re .no• e1S1~lO)'<:d to connect cert!.. in contacts or pt nela 5 e..n~ 6, 

which !or th" 'eke of cU:rit.y :-:111 merely bo indict.ted by stt'l.ting the 

cont:.ct poiuti:; thus connecteds 

SECRET-
,,--.--.----·· --~----......- -._,.. ________ - .. REF ID:A105026 

-lt1rrt-h4nd 

contE-ote 

ot Tl 

27 and 47) 2a and ;.al Left-hl"nc!. 29 an(! l.9J contects 

.30 and 50 of T2 

31 anC 51 

Pow or Lever 6l LUVi::l' 62 

contaot of Tl of Tl 

21 e.nd 2:? 23 and 

Counter Levor 75 Lever 71 

JU.en.at ot T2 o!' 12 

37 and A6 a and 

Levar 63 

o:t Tl 

2.4 

Leyor 72 

ot T2 

.43 

te-ver 64 

ot Tl 

2S ad 

Lever 73 

ot 't2 

4(. and 

Lever 63 

or '1'1 

26 

Lever 74 

or '?2 

43 

4. The circutt for the countor n~gnet 13 is a 8•~1es circuit 

paosing through all ten oonte.ct levers of tr:-~nsuaittera l and 2. Therefore, in. order that couttter l!l~\g?lltt 13 bo aotu.'ltcd, all cont·~et levers 

61 to 65 of tr~ns:a1tter l muet be in poattion~ thet are hom~logoue with 

thoese 0£ hOI!!OlOg·:lUS "'outset levers 71 to 7'J or tr~n:Jmi tter ~J if this 18 

not the case then no c!rauit is ocm~let~d through thB eountrr m-gn~t 13. 

'?b.1B will h!ip?en only- when ~.ilentit\:.ll letters (no mll.ttar w!l&t these letters 

:mr..y be) a.re air.iultgnacusly p'11!1ei:na tln,"uugh bot'l tr·lnBrnitters., in other 

words, onl1 "When a coincidonee occur~ will the counter •t•p !ol'lrarO. 

5. By e~tenei~n, ~~ nllt!b~r ot tr·nemitters m~' be "1.red tor such 

work, the number of counters being ono lee~ thQn the number or trane-

:m.t tters. 

6. In the toreaoing opttr~t1ons the counters or the ~chine •re 

6Ctua.ted by eoincideuce~ of identical letter•, bnt it is obviou$ thmt 

the lllachine m~y be ~rr~nged to count coinoiaencea o~ s~ecifio pair8.;o£ non-identio~ letter~. For e.xa.•ple, eup,ose it is nesired to tot~lize 

the nU"!lber or t!mas c.n A meets l!l lt in t':fo eetiuencee.. B7 :\\pp:ropriata 

wiring this osn b& done, eo th··t only when .1J. r ie f»l1JF1itte through one tr.~nl'!rdtter while an J. is paseine through the other will t-he coUJ1ter be 

actu..,.,ted. Thuss 
REF ID:A105026 

SEO:.. .. E.'R . 

_,_ 

1i 1i 7i 

"i( 

Th& principl~ herEI if.I that. fl:. p&ir O! homologoUB le'V9ri! Which ~re ill. 

hol!lOlogous positions (for coincidence or characters desired) must haTe 

their aesocie.ted homologous cont.eats connected together; a pair or 

homologoue levers which are in non-homologous positions must h8v& the 

le.ft-bP-nd contact ot one lever wired to tlle right-hnnd contact of the 

other, and vies verea, ell eh.own iu above sketch. When so '-'rr~nged it 

ie immaterial which letter com•a in which trauSmi.ttars the renults are 

the saae whether •!• io pa.ssin§ through transmitter l while •xn ia 

passing throu.g'b. transmitter 2, or vice veraa. 

7. Tha mt:chine mey also be used to count the :non-coincidences 

juct ao eaeit,. 

. a. By •xtension of the principle, it is poedble to count t.he 

nUJbber of coincidences between 3, ~' ••• different letters. For ex.?!mple, 1£ it is desired to count the number or times the letters A and B, A snd 

c, 1 and D, ••• eo1nc1ce, trcnemitters 1 and 2 are wired to count the 

coincidences bet•een A and BJ transmitters 1 and 3 are wired to count 

the coincidences between A and C; trcnr.l!!ittere l &nd 4 are wire~ to count 

the coincidences between A ~nd D, end eo on. It ia tor thie re~eon that 

the plugs in the panels o:r lf'ig. 1 t.re ohown as provided tor the ~19eibility 

of ostr.·.blishin& multiple conneotione. 

9. the machine r..7 be used tor other ccypts.nal)'tio purposes, tor 

example, determining tlle oryptogrn?hio period or a meAsage without finding 

repetitionl!l nnd faetoring the interv.l.ls between them. Suptlose a measege 

is t1uepeated ot having a cryptographic period between 7 and lS. Antium1ng 

a machine comprising 10 trane~ttare {w1tb 9 countera), th$ mese~ge 18 

prepared in 10 tBpe-copiee. Cop1 nur.iber l is placed 1.u transmitter number 

1. with the first letter iu the initial poe1t1onJ oopy number. 2, in tranaJA1tter 2 witn its 7th letter in the initial po~1t1onJ copy uurebar 3, in 

transaitter 3 with its Sth letter in the initial positionJ an·~ so on. The 
- - .. -----·----

REF ID:A105026 

t3BORil'i' 

... 4 -

machine ia st.~.rted an.:! th:.t counter which givec the grentast total 

number of coinoidenc•a sbcws :T'.lio~ t~p~ is in ·the corr~ot position 

a1 reg~rds periodicity ~nd thi& givea the p&riod. For ex~mple, if 

the lat ooullt~r g:l Vt38 thEr gi:·e~ tas.t tot~l, tho ?etr1od .is 7; if th• 

2d oounter aivea t.he are.:..t~et total_. the perio·l is 8, s.nr.! so on. 

lO. Suppo&e it is desired to .fin':! the inte1·vw..ls b•tween oeourrenJa& ot a epeoific lett.er in a. 11ase:·~s, for ex~mpl·a, A. The ;>lnt 

of trana:ait-ter l 1re locked in the 1tA" position, opanill& sw1toh .3S 

in the tJpe-steppin& mainet 3 of tr~nr~1tt~r l at tha aame tim9J the mes~~ga tape is pl~c•d in trnnsmitter 2, an1 taa •~ohine 1& ut~rtad. 

Only «hbn ~n "A• occurs on tr~ns~itter 2 will tha counter lJ bo :otu- at~:i" By inse.rti.n& a oollllter in the Oil"cuit or 2a&net 9 of tram-liitter 

2, t..>ie :nwnber or tst.lilps ·the tlpe m:::lcee before counter 13 1a actur.ted 

will b• shown. But thii oper: .. tor would have to ::top the ma.chine instantly 

an-j this wouli re·"Luire eharp attention. B1 eub&titutia.g c. rel.;.,- tor 

countar m~&nst 13, and placinc this relay in the circuit ~t the c~m switch 

111 the •~chine m~y be c~u~ei to &t3p ~uto~~t!e~lly. The counter in the 

c1rcu1t ot ·Lh6 t.:.pe-etGpping 112.cnet cf tr;·mdtttir 2 '!\'ill then show the 

interYt~l. 

ll. Other ueee tor tho mt.chinG 11:~y develop aa its .flexibility 'lnd l!nit~tioA~ becc~e better underetood. 

W~shiniton, D. c. -·· April 15, 1937. 

WILLI.Hi F. FRIE:V!UI, 

Principe.I Cry~tanal~et, 

Sign~l Intell1eence Section, 

War Plsnn and Trainini D1v111on, 

Office or tba Ohief El£D.~l Officer. 

This i.iw~.ntion w~E. d1Eclo2ed. t.o us in Febrll!\ry, 19~7,. by 

Kr. Fri,:!U?an. 

BB ORD'» 

--- --·---- ·- ---:.=-=---.-.--':"'"- -..