'' " 

.. 

•• .. 

REF ID:A273765 

WAR DEPARTMENT 

OFFICE OF THE CHIEF SIGNAL OFFICER 

WASHINGTON 

0CI O'M8l" Kl..-a. 

1. !he ·~ to whlah ;you nterred thb J10rn1Dg ••mad• a' •• lDtonal reque1t of 7our pradeoeaaor, Comnallder Godwla, and Lieut. Loven6al, tn 

OOD'lli8a'loa wttb a rather complioated clphor maohlne, Whiah was being oona1ctel"e4 

tor_. ill \he la-.1 .. ntoe. 

a. !hll 1nft•t18a.Uoa ex.tended OTer a pe,rlocl ot about slx mon~•• 

bu' I did not, ot oourae, deYote all ~ available tbm •o lt - onl7 8UOh as 

ooul4 be •puoe4 flt• IQ' more 1-41a '8 dut :lee 1n '11• ott1oe • 

a. 9le amq passed tbl"ough aeTeral •'88••· rust, a oaretul 1111'-

w7 •• md• ot \be '1pe ot 0171>\08J"811 pro<luoe4 bJ the &ppe.l!"ataa. fhl:a 1zm>lTe4 reaearah into Ule maohanioo-eleotrloal taaiurae o.t the maohlDI, -iv ot which 

were DOVel, and resulted ln produo1J8 aeyptograme ot oona14erable CMDpleX1V• 

))8~11•4 1DTeat1gat1on. howwr, oonYlDoed me \hii.i ola1.me tor 1ndeo1pberab1llQ'1 

ewn ot a relaUve nature, put tortb. b1 those interested, wre not warzoaaw. 1t 

all U. faotore aoDMo'8d w1'h the ue ot the machine la ~ mllUal"J or a'Yal 

aenlce were tal&en lnw oons1derailon. 

4. ~ r.ext step was. ot course, \o u."emp' '° est.abl18h a body ot 

prlnolpl•• and a •\hod of prooedllft tor dl"JP\aDa17tlo nduo,loa ot the dl•patoh-

•• ""11oh would be produoed UJldeJ' eel"f109 oond1'1o:u. lJl "111 1 waa euooe•aM, 

aad 1aU1tlH JQ"Hlf '1la\ auoh 1'94110tloa •• •t •1117 poul'bl• 'b11t ftJ'7 praa'1-

oa,le. 

&. !here reniJ.ned, ho11111wJ'. the qm1,1oa of 4emonava'1!11 the V.t!l 

ot '1Mt Yarhu llJ'potheMa ••'a'blllbe4. .&. Mt ot \ea '8•' •••aa•• was prepaet. 

'-1 the Cede and Staal seo,lon. \uecl upon the aa.-p'1aa th&\ tlle -., wouli 

Jmn all Uaat '11ere la •o 'be lmowa aa re&aft1. ihe •ahlna and 1 '• ttmo' lGM, lnlt 

wul4 •' 1maw tM ·~ ot '11.e olp'ber wbeel1" !he badloawr wol"4 to• euh •1-

HI•• la or4•r to ._ltl• Ula nol,,._, to "' hls maahlne p!'OJMll"lJ tor •olpber- 1111.-.. lhatnl la ol•ar a ..U •aaap, ae ti• wv.ld 'be ~ oue 1n atn-.1 

pn.o\loe '811••• ._ .,.._ wre ,_..._ •. ...,11oa,ed bJ b ue ot a oo4e boo:t, 

or •- otbe• 181l41a1'7 o1}1Mr 81'••• for dl1&111•1Jts '11• iadloa\ora. 

a. !M fin\ ot fben 4hpa\ohea •• eolwd after approxiaa'811' om 

WMk'• laieulw 1wq of 0. 4ata 'baH4 on all ten •a•ageh !hia le11gtlb. ot 

u., howftr, g1w1 111 rellabl• ba4ex ot the lflnsth o:f' tlM \hai would be requlnt la ao'•l praotloe, 1Moauae !1aJV other tac\ora, a110h aa paacmml, 'f'Ol-

- ot data, speolal 1nf.-,loa t.:rcm gemnl intelllpaoe. and ao oa, wou14 &11 

haw a .,.r-, cletlalte ad '1iportaat lntl,.... on '111• qU1a\Soa. u JOU an •11 

-1'9. I wae all alom, a• regar41 \he ~•111 ot the data, and had .,, U.. 

allpteat l•a u to &a• mv ••Al• waa uout. It 1• 1111 oplaloa Oa• w1'1l a 

lop, wll-va1m4 ataft, and aoarcea ot ou'a14• in\elllgem• Uiat AN ...ii, 

a•llabla, th• pro••• o01114 M aooaaplltlhe4 wlth1a a epaoe of '1• lhon ••ua'b 

pproved for Release by NSA on 09-12-2013 pursuant to E.O . 

3526 
REF ID:A273765 

to make the anal1•18 of messages ot major 1.J!'lportanoe "1817 Tal.uable to an ene111. 

'I. Regardleea, howeTer, of how long it took '° solve that first maaaage, the solution of the rest ot the!'!'I was made very mua.li simpler a.a a :.r&aul t ot 

e most interesting se~1ea ot ana1Jt1c steps de'f8loped coincident with the solution ot the first massage. ID faet. lt was ahoW'll tbl.t the solution ot but two 

or three· 11!1811 of text of one meas.age was all Ulat -.s neoensar7. 'l!hls would be 

dU'tioult, perhaps, dependil'lg on how much text '\"las available, bu~ onoe done, '1'le 

rest follows rawr eae1l7. 1 do not mean to sq that only •o or three 11nea 

o·l cipher text are neceHBl'y, but th~t the ru.""·lt•l~ ot tho datu baned on a oonaiderable volume ot uxt, when appllecl on11 to two or thre\l lines of om mea1age, 

will reau.1 t in the soluUon of those lines, L\l'ld t.rom thr.t, t:t:.e rest tD•lows 1n 

rapid order. 

a. It 1a necessary to say thnt the wiJ'ing of the pla'\ie tn the rear 

ot the ~.nhine wna knmm1 to me :ln th.lo test. 1 t havinc henn nss\UOOd thn.t ~ts 

part of tl1a eleotrioal arrangements would be the same for all maohlnes. It seeaed naoeasnry, of Of'Hll'ae. to cntab11eh procedure for o.nnl;rnin wtion the latter is 

un't:nown. While no actual massages were presented for solution, on account of ~e 

laolc of t imft Blld personnGlt neverthelesE r; aet o! .n'Stmt 100 massage:: had been prepared somo Ume prevlousl11 and the cipher dlepatohea were oa.retull1 examiDed 1n 

oonneo'Uon with their plain text, nnd d1agrame of the wirlDg ot tl141 oipber ~oela. 

The da.tu showed tht:i.t given a sufficient number of messages (tile tra:ttic of NAA 

for one day durine i:-.ot1ve oparr..tinns vroulrl bfl mo'.!"e th;;n n11.ff'lclcnt} nolution 

oould b6 achieved within a practicable length of time. I would eTGn go ao tar 

n0'\'1 ns to -ventur<'l the opinion tlm.t 5. t mi(!ht be done V'U'h t'hirtr or- r,o oescatS••• 

9. Of eourso, Vli th nn lmderatn:nd\nf o! the ~chnnfoa of the c\11F.lyo1a, 

nU{7£FlsUons for the improvement of the apparatus, with a view to increasing the 

degree of eeornoy, presented thf'lmsel ves. !hu:e, nno t.he l"lethod of solution were 

~o~ioatad to members of your section. 

10. I wish to tnke this opportunl ty to say that itr. Bogle of your 

~ctton rEinderNl very Taluable a1ebtance in the way of oomp111:og gpecial table•, 

u.der my direotion. I also wish to add that I was nry glad to haTe had the op.. 

portnni t7 to conduct this 1nvef!t1gaUon1 tor I had the good fortuno to de'f'elop 

eeTeral new principles 1n analysia, the value of which will no doubt man1teat 1\-

eelf. in rtry m"tl work at sorie. future tlr!e. 

w. F. i'rte~.n, 

CJtyptanal.1'st, Signal Corps.