• 

.. 9 REF ID:A58828 " .... I ·, 

Blt.4 \.._,} <J ; 

·I: TOP SECR$T 

EO 3.3(h)(2) 

PL 86-36/50 use 3605 REPORT' ON VIJIT TO li'REN?H "SEf'TION DU CHIFFRE" 

' 

On 21st May 1951, I went with ~dr~ G.Chiles, U.S.N., to the 

French Combined Forces Headqu.irters ( Etat-Mf:!,jor Combine' des Forces 

Arm.ees) ) at 51, Boulevard de la Tour Uauboiire in Paris. We had been 

instructed to report to Colon~l VE."YRON LA ~OIX, to witness a demonstration 

of the French modification of th~ M-209-B H~gelin. Most of our subseauent discussions were ca.r1·iud out with Commandant ARNAUD at the Ministry 

of-War. The evidence leads us to belfove. t.hJ.t he may be the head of the 

French Army cryptanalytic bur~~u, rmd that our mo~tings took place within 

the walls of that organisatii:m. Th~ ~·,t~noaphore was very friendly throughout, and we. gained the impr..:.ouii:m th•.i.t thl.if wou.ld have liked to tell us 

more than they were allowt.d. It iu l1rob ~blu that ..tU'na.ud would welcome 

t,:,chnical collo.boration both on cryptoc,r·.:r.pht and cryp~analysis. 

2. A summary of our ~ .. ·i:cl'.lsi~us is eivcn bcl·Jw. 'Port II of this 

report contains a personal r\;cc..:l'.'d of' ·~h .... vi$i t, Part III a description of 

the French modification with so~~ communts $n its pr~cticability and 

imp1 ico.tions, Po.rt IV an outlint.. -')f ~cr1 clt.ictrical keyboard modification 

of waich we were given som& dut'.li] :..: • . . 

3. .~fte.r careful study r f t};,, Jir ~:"l ch n:odii'icr.i.tion t,, tlie. M209, we 

r€::3.Ched the conclusion th:it it is :1 pr:1ctic$.l proposition. · They have gone 

to considerable trouble to circumvunt th ..... r.:t .• ctical sn~gs. The changing 

of the alphabets is no moru t~di0us th :m th·.f. norm-:..1 ch:mgE:l of pin- and 

lug-settings, .ind con bo complut~d in about 1C minutes. Th~ danger of 

.error is probably' loss thlil.in th~ pin-sc.:ttines, ::md is count~rocted by 

th~ currying out of u 26-luttur check. Th~y cluim that ':li'ter ~ little 

pr3.ctice encyphermt1nt with u h:1ttcd wh..;ol ia n~ slow13r th.:m tho present 

system; while experiments will b(. !h.~dud ~n this, wo consider th.:l.t this 

cstimcte mo.y prove to be fair. 

4. As 3. result of t.his, it f'Jllows tJ:>,·:.t '.l frequent change of 

:ilph1bet is quite pro.cticablo, 'llld th~ Fr~n~h in fQCt propose to chlilge ~t 

least everf other do.y o.nd possibly d.:ily. _This mE:ilns th'lt the alpha.but 

~::iy be reg~rded as uncompromisuc, 1.11~ c~nsidur3.bly 3.lturs our pr~vious 

misgivings on s&curity. A dut1ilud s~curi~y study must now be made of the 

implico.tions of this modificuti~n. · 

5. The:. French will have 1800 m':l.chin~Ef by the 13nd of this· year, 3Ild 

will pr&sum3bly introduce it thr~ugh0ut th0lr rll'rny shortly ~fterwo.rds. The 

modific3.tion of these ms.chinos will t...ik~ ~bout 8 months, at a cost of 

£B p~r machine. It is thus cJmpurutivuly quick :md cheap to introduce. 

6. Whatever the result of ·:-.ur fin.11 sucu.rity E:iva.luation, it seems likely 

th:it the modified In:lChino will provide.. :m ilcloqu.1te solution to the problem 

of French internal mi:J,.it;!l'Y tr:lf''ic. It c1.lso s.::ems probo.ble that it will 

provu sufficiently s&curc for third-1\.ivel N!~'ro tro.ffic, at least until som.:1 

bvttur machine is availablo. It i~ thor~f~r~ rocommGnded th:it it should be 

gi·1on serious consideration c.a -~nu ~,·;ssiblc.: s·.1ution to this problem. 

PL 86-36/SOUSG 3605 

TOP,SECRST 

Declassified and approved for release by NSA on 06-17-2014 pursuantto E .0. 1352a ' 
I 

I 

I 

I 

I 

.• 

I_ 

" 

I 

0 REF ID:A588.28 

I 

TOP ·SECRfm:T 

- 2 -

PiffiT II. RECORD OF EVJ!TS. 

lLt Combined Forces HeaQ.quarters, w$ were kept wo.i ting on hcur 

until Colonel Veyron L~ Croix returned from lunch at h~lf p'lSt three. 

During port of this time, we were entertain~~ by his Adjutjnt, Commandarrt 

Lign.ac, who cl~imed to know nothing :ibout cYJl>hers. From his convers~ti~n 

~nd the diagr::uns on thG walls, it appo.:lr~d tlio.t we were probably in the 

French equiv~lent of t~el bnd th~t the section was m~inly concGrnbd 

with such matters 5S frequency alloc~tion. 'Cdt. Lignac spckc English 

r.;.'.)derately well Jlld h~d often been in Londont and had h:id contacts with 

2. '''hen the Colonel fin.J.11\Y .1.I'rivt..d, he did little more th:m introduc13 

hims..:ilf ::ind ::i.rrange for n car to to.ka us to the Ministry of. '!Jar, where the 

modifigd machine was to be demonstr::i.tud by Comm.andont ARNAUD (whose nome wc.s 

f:imiliar as the French rC;;~rcsentat:i.ve on the. Ni-1.TO cypher committee). The 

Col':'nel did not speak English. He \.w::is enthuiSiastic concerning the modified 

m:ichinb, of which he s.::iid that 1800 would be available by the end of 1951. 

He so.id th.lt the modification could !).lso be a:iJ:;;>l~ed to another m:ichine called 

th\:l "!..igline"; when asked 3.bout this. 1-J.tter •a.chine, he so.id th~t tiRNAUD 

w ·Uld be able to give us full d~t.:'!.ils, 

3. '!Jfd thun had to w:ii t .:ibcut 20. r.linutoa in the C')Urty:ird while a c:ir 

w:i:s found for us. We left Hf::.adqu'.lrtors n::it porticul!lrly imprtiSS1;:;d by the 

afficiency of th~ ::irr!lllgements which had been made for our rt:::ception. 

4. . At tht::: IJ:inistry cf War ( ::31, \Bculet.:lrd Saint-Gerrn.:J.in), we were 

conducted up to the "Section du Chiffre'' on tlle third floor. i:..t no time 

during our visit were we a.sked for .JD.Y pr::>~f of identity. Our W':J.Y to the 

Section du Chit't're was blocked by a. d.Jor \mark~d. ''No entry except to 

authorised personnel". f\. number •:.f fo.ctors ¢ombined to mJ.ke us btiliove 

th'lt we were in the French Army crYj'.'tanc.lytic bureau:+- (o.) French Sigint 

was known as "Section du Chiffre" before the \Val'; ( b) the b:oks inli.rnaud' s 

lihrary includ·od 111 the st:J.ndard crypt:in:ilyt:i,c works ; Bcudouin, GiviorgcJ, 

Y::irdley, etc. i other v0lumes included ..m 1\BC Telegraph Code, Btintleys) ~nd 

Swucish 3.Ild Spanish dictiono.rius; (c) thure was a. general air ct' secrecy 

Ellld great care w:i.s takE:Jn to ensure th.:it no rloors · .• were left open f')r our 

ins~ection; ( d) one piece of (:;Vidence c1uri\ng the visit sugeest&d th:it 

l

. Ge.rmG.Ilts wdere employed in the saction, onfd the French Ji.rmy is known to h:ivc 

recrui e certain Germon cryptan:ilysts or work i.n their Sigint orgo.nisoti.:in. 

If this theory is correct, Cdt. J'i.rno.ud, .lS Chef de Section, is l)rosum::ibly 

the successor of Colonel BERTR.'..N. 

5. The remninder of the tim~ was spent ~n J\rn3ud's 0ffice, 3Ild we were 

n:it introduced tc .my of his subordin:itos. Ha began by s::iying th:it ho knaw 

insufficient English to expound his subject, and the discussions were carried 

on entirely in French. As Cdr. Chiles d~es n~t know French; I :ict~d o.s 

interpreter throughout. It was u~~::irent, hOW$Ver, that 1.rn~ud underst0~d 

most of wh~t we said in English. He was obvi9usly mast~r of his subjoct, 

very shrewd, with a dry wit; we loft with a very fav~ur3ble impression of his · efficiency. 

n. He beg:m by a.sking wh<it we wer~ expeJi'ts \in. I said th~t we 

representl3d the users, ::md h~d come to investi$atfd\ the practic.'.\bility of thtj 

modific:ition which had beon described to us. He expressed himself disa?~ointbd, a.s he had hoped th:lt we should be in a p:>Sition to discuss thu 

security implications. I replied th.i.t we were not\QU'llit'ied to do this, 

althou~h w~ should ~rob~bly bs abl~ to underst~d any such ?~ints which h~ wish~d to put ~cross. 

-- ~-----~ EO 3.3(h)(2) 

PL 86-36/50 USC 3605 

TOP SECRElF 

. ! ' 

I 
• 

··~ 

I I 

; 

REF ID:A58828 

TOP SECR&T 

- :3 -

.. -\ 

0 

EO 3.3(h)(2) 

PL86-36/50 USC 3605 

? • Ho said thc.t thtiy had undert::ikt:ln 'the modificati:ln owing to the. 

basic security weakness of th..i ::;;iresent machine, /by which three messat,es 

with tho sO.mo indicn.tor can ~o r-:=ad "and theoretically, even two". 

It seoms almost certain that h.:; in fa.ct knows/th:3.t a depth of two is 

re9.d-:..ble; he referred to cepths of two la.ter /in the conversation; anrl, 

if he (;ffinloys Vocgolo, who was a Germ3Il expert on the M209, he must 

cort3inly.be a.ware-tfiit the Germans ex;;>loited such depths. His 

\ 

reticence ma.y bo an indication th3.t the Fre:μ'ch :ire currently exploiting· 

this weakness, ruld do n~t therefore wish to,broo.dc11st the possi~ilities. 

8. He th.:n showed us the. .nodified ma.c:tiine, a.nd gave us ample 

~p,ortuni ty to er.Jeriment with it., ch3Ilgt:t the alphabets, etc. Poss~bly 

owinc: to the f::i.ct that thi:i modific:ition has.been patented, .he refused 

to 1£Jt us ha.vt:l :i modified YJheel to take aw~y, but allmved us to make rc)ugh drawings·. . lie sa:i.d th:it the alphabet Sh".>uld be changed according 

to traffic load (he refused to commit himseif on what should be regsrded 

as 9. S3.fe load); he thoueht.it should be ch9llged every other day at 

Division, and that it might bo desirable to· change it daily. Aa :i 

r£..sult :lf our inv~stigo.tion, we rG:iched the conclusion that tht'ly had donu 

a very nice job, !lll~ th~t a.c~ily ch:inee should be a perfectly pr~ctica.ble 

pror>oBition. A detailed descri;>tion of the modification, production, 

cost, etc. will be found in P . .-.irt LI!. 

9 ,. Arnaud em:-hasised th·J.t he considorcc!l tho security of the modified 

mo.chine very hieh. Depths Jf two or three could not be read, and even 

if. users empl Jycd the wrone .:i.lphab-:;t, or ma.de mistakes in setting it up, 

he did not think tha.t security/would be:: jeo.;?ardised. Ht:: thought, in any 

c~se, th:it such mistakes woula bd of re.re o¢currence, sine~ !l 26-letter 

check is printed with the keylists; if thi$ check is carried out, any 

mistake will be illllnudi3.toly .obvious. 

1'() He was pru:;::iaroa. t 1J iosue a. sc~~ara.1).e wheel wi t.h the normal stra.i@lt 

nlj_)ho.bet as well c.s the modification, and g!llve three rE::asons for this :-

(a) if the u.s • .hrmy refused t~ !ljo,t the .qtodifica.tion, they would r~quire 

""uc talk to the .Americans/in th~ luss SE::cure machine; (b) they mi~t not 

wish to eive tho modifitid me.chine tc ccuntr:\&s whose security arran(;timents 

were in question; (c) t~oy mirht use the ma.chine unmodified in daneerous 

c.re::is where theru wa.s risk of capturt3. 

' 

11. When we hm':./fully discussed the mQdified ma.chine, Arnaud 

volunteered that they w~re tlosi~ning on eleQtrico.l version.to work with a. 

kuyboard. This would use th& S9.Inc :;;irinCiple ·as the modified machine, and 

·many of thb same parts, 30 that one type coqld work with the other. W& 

expressQd considerable intur~st in this, pOI!ticularly in view of the.speed· 

which he claimed "ffr:>r it, ·anμ he. :finally proc)ucecl a drawing for ~ur inspt:iction. 

I suspect th~t he/ had re'"l.5'.)n to r1:Je;ret this afterwards, as the drawine 

c0ntained two notew'>rthy fuuturos :- (a) Th~ German word ''Klartext" on the 

~il:iin-1 ml-uo.ge ta:;;io 3ueeosts. ·th:it the m!lchi~u was designe.:l by a Gt.rm!3.Il; 

(b) The a11pco.pnnce of numb""rs on some of t~(. wheels sugc:osts that the 

cycle ha.a been/ incr.aa.sed, and thc.t it would .cert':l.inly not work with the 

present machine. Tlw wheul-periods would a.:ppear t') bo 29 31 •••• 35 •• 

12. A reconstruction of thu drawinc from memory, together with any 

dotn.ils which Arnaud f:'.::l.\·c us, will be found in Part IV. I asked Arnaud 

whether he/,roposod to includ~ the figure substituti')n system as for the 

present Ill()dification ( se;e P~1rt Ill ) , and in that ca.se whether the mo.chine 

- 3 -

TOP SECRET 
.---------

(J 

REF ID:A58828 ........ I 

I 

I 

I TOP SECRET 

. I 

- 4 - EO 3.3(h)(2) I 

PL 86-36/50 USC 36$ 

would print figures on the tape or only their letter equivalents. He 

replied that he was including the substitution system, but tbat only letterc 

would be printed. I suggested that, as in any ·case he had/to modify the 

printer-heod to priut two tapes, he might consid,er a shifting printer .so that 

tho numbers could be ...,rinted direct on.to the ta.'Pe instead/of substituted 

afterwards. He agreed thllt this woula be a. useful facility, and SJ.id 

that he would consider the possibility. 

I 13. I then asked Arnaud about Colonel Veyr:on La Croix's statement 

1 concerning "Aigline". He o.~peared rather annoyed and said that the Colonel l must be thinking of the other French machine, the B2t1. This worked on 

! c. different princi,le, ond wa.s quite unsuited to the modification. Too 

: Colonel was not a cypher er.,Jert, and did not ·knQw what he was talking about. 

·\: The following morning, he asked the Colonel wh:rl', be rn&o.nt, o.nd it fin:illy 

emerged that "Aiglinc" wo.s the Colonel's rronunqiation of Hag&lin; he h<id i merely me.a."l.t that the mod if ice.ti on could he inc}udod in Ha.selin models other 

. \ tl'f.-:m~l.he M209 ... ··The subject of B211 W'lS thus i~troduced accidentally, ::i..."ld 

• agnIIlst.Arnaud' s will. 

l 

14. At the end of the d:iy, ;;m were nsk.Od to return the folloviing 

~1.orning, :is the Colonel would like t-:> :Je.e u.s before our deplI'ture. ·~"':.ri.···. 

Colonel w.::i.s at a. meeting when W6 ar:-.:-ed, .and we,s again ho.lf o.n hour } "'-'~-~ 

for the a;;i,ointment. During this time, we war$ able to usk more qul?s~,ir-:~·: 

;J.Ild do a time test on the chnni::inr- of tho •:il:pha~ets. 

15. 'A'hen the Colonel arrived, ht:J /bdeen by st!iting that the modified 

machine was eminently suitable for use• ilt level$ where spt:;ed of enc;n)her:i1cn+. 

wc.s not the first consideration, but .where wei{!l1t and lack of power supply 

wero the muin factors. Ha thurt3forti envisaeed that it would bt:. used only 

:it the third level - forward of Div-ision; he thought that the electrical 

model, when it wo.s rt::o.dy, mir.ht 111011 be sui t.3.ble for the second l6vel. 

16. He then asked whether vvc knc.w wha.t Hag6lin models other than M209 

were av'J.ilable to the vt:i.rious NATO countrias. Arnaud had previously st~tcd 

that h.; beli6ved M209 was ava.ila.ble to ·1.ll NATO countries excc~t Norwa.:r· 

a.nc It.1ly. I re-plied r9.ther/BUo.rdsdly th..~t the. lbgulin m:ichine W3.S of 

c0ur·se :produced in :i number of !'ll·Jdels by the sWedish firm, but th:J.t we did 

not know how far such models might bi:: used by other countries. 

17. Ha then a.sked ua wh::..t wa h'3.1 dee ided. "le replied tho.t it W!lS not 

up to us to decide, but m~rely to r1;;:)crt back i.n detnil wh:it we h~d bean 

sho•1m a.nd told. Acco:;Jtance of thc.;ir m0dificc.tion would depend u::-on a. study 

of the security imy.'lliccrt.ions, on which we 1111t1re not in a position to corr211(...:-.t,-

~d· u::lOn what other systems wero ::::.va.il:lble tlS on alternative solution. On 

th.::: practical side, we should :Llut it forward :is our personal opinion th::i.t 

they had made a very_/gcod job of the ::nndifica.tion, thfl.t frequent chaneinc; 

of the FJ.lphnbet in the wc.y they ;i't'O!mr>ed see:med to be an entir1;;ly ;ractic:l'tilc 

-;-roposi tion, and that for this ronson Wl:. should recommend th.1t their mc.c:hir..a 

deserved seri-:>us consi.:i.1::rntion as om. ::-·:>ssible: solution to the :t'roblem . 1:"" 

.:.hird-level NATC /COm.."llunice.tions. · Th0y both e~ressod themselves very 

sa.tisfien with this statem(,nt; ii.:::nc.ud. said t.li:lt they had of course C:0ne 

a full security/ O.pi)r&ciation of th;;; machine thamselves,. but that n:itura.J ~-Y 

~ach country must makE up its own mind on such a matter. He expressec· 

himself willing to go to Washington to demonstrate thi:i machine if required: 

o.nr'\ the Colonel su ""i>Orted this. 

- 4 -

TOP SECRET •• 
I 

I 

I 

I 

i 

;. _ ....... ' 

0 REF ID:A588~8 () 

- 5 -

EO 3.3(h)(2) 

PL 86-36/50 USC 360 

18. Several times during the morning me ting, the Colonel pointed 

to Arnaud' s safe and suggested that he had some · nteresting doc_uments whi.ch 

he ought· to show us, whereupon Arnaud would r'epl . that there was nothing of 

interest. . At one stage, quite e. volubl.e argwne t proceeded between them 

as to whether or not we should be shown these ex ibits, in which - unfortunately for us - Arnaud ~revailed, We had the i ression throughout that 

he regarded the Colonel as a thorn in his side. 

19. We felt, however, that Arnaud would 

to ·co-operate on a reciprocal basis. Both men 

and there is little doubt that if w~ had been pr 

discussions on security we. -should have been give 

into their methods and organisation. 

20, We parted on very friendly terms; w 

way in which they had answered all our questions 

into details on the ma.chine; they expressed thei 

Governments had made us available for such a dis 

stated that he was fully at dur disposal if we 

meeting in any way, 

ave been very willing 

re fairly forth.coming, 

pare<;l to enter into any 

a ·considerable insight." 

thanked them for the 

nd allowed us to go 

appreciation that our 

ssion; and Arnaud 

hed to follow up the 

'--··--·----- ~----------

·I 

·I 

i 
--------------

• 

t..+4 

G REF ID:A58828 (._) 

TOP SECRET 

- 6 

PART III. M209 MODIFICATION. 

EO 3.3(h)(2) 

PL86-36/50 use 3605 

Two main alt&r~tions are involved in the French modification -

rapla.cement of the printer .:.:.lphabs.t by r.:;mov~nble seG1I1ents, and replacement of the alphabet on the sotting-\•1heel by. rerr.ovea.ble seements. In 

ad•U tion, a n<:;w setting-wheel contai-nins the nurn.bc.rs in fixed numerical 

order has been added outside the normal wheel,/wbich has the doubl.e purpose 

of lockine the a.l;lho.het Su(;:ments in p0sition,/3ncl providing a letter-figure 

simJ:)le substitution. Th<"> sp3ce-mechrmism, and consequently the letter 

z on the two alphabets, h::::.s rem.:iined un:tl tared, and the Z segments are 

locked in positi~n. 

2. The rnodificati0n is issued os ~ complete unit and is easily 

detacha.ble from the mo.chine. (Fig. ?) Reference should be made to the 

accompanying diagram. The shn.ft on the/ norm3l .M-209-B convertor has 

been cut about half \'ffJ.Y bb·tween the gea.:r wheol .$d the printer wheQl; a 

notch (g) is cut on ons side of the stwnp, and braso bushing installed 

inside the hollow. (Fig. 8). The mo<.Hfied unit is fitted with a projecting 

lug (f), which fits exactly into the /notch; it is then locked into position 

by inserting a butterfly ;:;crew (h) through the hnllow shaft of the unit, and 

screwing it into the brass bushing. ~rhen scr~wed up, the butterfly lies 

flat with the surfa.cc of the out-:..ir /knob. 

3. On the print-wh0(Jl, (Fig. '4) the type segments ElI'e replaced by a 

narrow taut spring (e), ::ittac!led/to each side of the fixed Z segment. Each 

type segment (Fig. 5) hns n hook/ o.t the inner en,d, which is inserted. by 

holding th& segment vertically /and sliding it undl:r the spring (Fie. 6); 

the type_ face is then lowar.;d into its normal position, where it is held by 

' the spring. To remove it, pull it into th.:: vertical position with a pair 

of pincers, and slide out thi:;i hook from under th,e spring. 

4. On the setting-wheel (Fig. 3), tho a.lpho,bet is ::igo.in replaced by a 

spring ( d), and beds i'or the:: lt!tter-set,'Illents are hollowed out. The segment is 

slid horizontally into itsibod (Fig. 9), where it is held lightly in position 

by th~ sprine;. Very li t.tle pressure is required to slide the segment in 

either direction, but the spring holds it su;ffioiently to prevent it frorrr 

fn.lling out while tha rernainine se€Jllunts o.re inserted. 

5. Finally, the.re is a removt:abfo annulus ( Fig. 2) containing the 

i'igures.O-~, 0-9, 0-4 in order, with one bl!.lil.k sesment coloured red. Inside 

the rim of the a.nnulu.s srt:i three short slots, wnich fit over three shallow 

knobs (a.) on the face of the setting-wheel (Fig. 1 } • The Wlnulus is then 

rotated slightly, so tha.t the thrc.e knobs are"hald in the slots, and a spring 

on the face ·or the/annulus (o) falls into position behind one of the knobs to 

hold the annulus in position. Tho ennulus is removed by raising-this spring 

clear of the knob/, .::ind rotatint: until the slots aro released. ·It will only 

fit !3-eainst the setting-wheel in one. position, Which throws the red segment 

.:J.fainst the fixed letter Z 011 the: sottine-wheel. 

6. In order that t·he mo.chine should decyphe;r, it is ossential th3.t the 

alphabet on the print-whe<:il shoulJ be in rov0rsod ordt;r from tha.t ~n the 

sotting-whc~l. In the mnchinc as shown to us, tho alphabet employed was 

reciprocal, /so that the machi11t:: wmilrl have ducYPherad equally well with the 

pr in tor alphabet in tho srunl:l ordo;:r. Arnaud. wo..s a:rr;>arently unaware of this 

unnecessary feature 1 which w;;ulCt be a slight weo.kneas if used in practice. 

- 6 -

TOP SECRET 

I 

I 

I 

I 

I 

I . i 
....... 

·• 

. 

\ 

I • 

I 

I 

I 

REF ID:A58828 

TOP SECRET 

- ? - EO 3.3(h)(2) 

PL 86-36/50 USC 36Q5 

? • The purpose of the numbered :m.nulus, in addition to/holding 

tha setting-wheel segments firmly in position, is to provide/a. means of 

encyphering digits without s,elline them out. A letter such o.s W is 

taken to indicate "numbers follow", anc. the user then en cyphers any of 

the alterno.tive letters opposite the fi~es on the o.unuluS; in 

decyphering, these are ::;>rinted as letters, which :r.i.ust be/Substituted 

manually, by reference to the setting-wheel. When ency'Phering important. 

numbers, or when there is danger of corruption, numbers will either be 

• spelt ~ut in full, or the substituted letters repeated/. 

8. The ma.chine which was :'.iemonstratc.d is the only one o.t present 

av'3.ile.ble. 1800 machines have be&n contracted out/ to a firm (which they 

have security vetted) for modification., and these ere expected to be ready 

at thfj end of 1951, i.e. ei~ht 1nonths from the time of placing the order. 

The cost of modifying each machine is a.bout 6000/fra.ncs (£8). The 

modification is thus quick and er.ea~. 

9. Although Arnauu was the inventor of/the modification, it has b1t1t?\ 

patented by the ·man responsible for de,rel'.:ipm~nt.·~ ·· ·rr· ·1T s"ii.ouid be .. a<iop.-t.e~ 

oy other"countrfe"s, ·1 t ":ts ""tiieir" "intenti"on" tha.t I those countries should 

modify· their own machines, and they would h.ave to purchase the patent 

rights. Arnaud offered to put us in touch with the development authori t~· 

if we should be interestod, and was obviously e..~xious that the question of 

the patent should not stand in the way. · 

10. When the 1800 mo.chinas 3.l'e r~ady, they will be sufficient to 

sa.tisfy the ne~ds of the French Army,/but not of course of other 

NATO n:\tions. 

11. Together with the modified unit, they a.re supplying special boxes, 

containing two drawers ea.ch divided into 25 se.gments lettered A to Y. 

These will be used to store the setting and -;:>rinter alpha.bets, and it is 

intended to issue three sets of.ea.ch with every machine. Thi~ means that 

if a. segment is lost there is a re::;>l!lcoment· imme0diately available; it 3lso 

enables the user to .om-iloy a different set of type when settinc up the 

new key on the print-....,.hecl,wi"th consequen;tly l.ess trouble from inky fingers. 

12. After ex,erirnen ting with the alphabets for some time, we both 

reache.d the conclusion that changing the; alpha.bets is comparatively quick 

and simple. · It is slightly "fiddly", but no more so th9ll resetting the 

pins :md lugs. It took/us 13 minutes to effect a complete change of 

o.l:phabet key; this was/without previous practice, and without the help 

of the lettered boxes, /whi.ch enable the correct letter to be found moz·e 

q~ickly. Arnaud esttrnated thut the ch1:Jll5e cc>ule easily be done in 10 

minutes vri th _;;>r.lctice, encl we endorsr:;d this view. The conclusion is. that 

this extro. process ttlkes no longe:;r and is no more liable to error. than the 

existing chi:inges of/ kE::ly, and co.nnot be rot::;urd.~d as in o.ny way o.n intolera.blf 

burden. 

13. Arnaud ha:i nlso curried out tests on the s:;;r~d of encypherme.nt 

using a hntted settinb-wheel. He f0und that en 1veraeE::1 operator was 

slightly slower than usual for the first half hour after the change; but 

that he soon "'becsrne used to the new alphabet, ar1d used it as quickly as the 

present system. ·While we did not uX)eriment with this ~t length) we fo\ind 

that it was.uneX'£)ectedly ee.sy to find the correct letter, and we believe 

th!l.t his estimate is not far wrong. 

- ? -

TOP SECRET . ' ·- .. ·- .. -· .. ------.. -·- ------· ·- - - --·--
• 

• 

..... 

REF ID:A588280 

TOP SECRET 

- 8 - EO 3.3(h)(2) 

PL 86-36/50 USC 3605 

14. He had had no opportunity to carry out p~olonged tests on the 

print-wheel. He expressed himself confident that the strain on the s~rine was very small, and that no trouble would· be experienced from 

this source. 

15. It e,~pears th!-lt the bTeo.tcst do.n£er from the cho.nt;ins alpha.bets 

is the possibility of sotting them up wrong; if o~erators/ carry out 

the 26-letter check as ordered, the mistake will immediately be spotted; 

::ind the danger is probably less than that of mD.kinG a mistake in the pinsettings. 

16.. If we accept that the modified M209 is a priJ.cticable propositi~n, 

it ri::.mains to ass~ss its security, It se~ms likely/that the French ho.ve 

not f?One further than to cecide that depths are unteadable. Our previous 

sccuri ty doubts were based on the assumption that /1 t would be imj;'lracticable 

to cho.nGe the alphabet very often, antl it ·nust therefore be assumed 

compromised. If it can be chonged frequently, however, a.nd the French a.re 

prepared to change it at lea.st every other day _mid possibly doily, it c.'lll 

be assumed uncompromised, and our s~curity view must be very different, 

17. Attacks based on c"!.epth are defoa.ted ,_/and simile.rly cribbing attacks, 

unless the enemy has a cribbed depth of two. .An investigation must be 

mo.do, however, as to how far statiatic~l nttacks nte still DOSSible, and 

what will be thE: effect of the ilddition:il/busts which may occur if the 

26-letter check is not enforced, It SufilmS likely that our conclusion will 

be tha.t it is not as good o.s we would l_ikc;; for our own use, but that 

(n.) it solves the problem of French military traffic, E.llld (b) it may be 

~cce~table as an interim system for third-level NAtO traffic until 

:somsthing better is a.v1J.ilable, 

- 8 -

TOP SECRET • ------'t ----- •••.••.•• - . . ·- . ·-.... . .- .... ---· 
•"°'\ I •._,I 

.. 

. 

... 

.. 

I 

i 

,. 

. 

l" 

l 

' 

kit' fb:AS992§ 

- ··- ... ·- . ..,., • • -.. oao • • •. 

,,,,...,... _____ _,,,, ·-- ...... ": ....... 

/ /--· ~·--- .. • ) (lj ......... 

. · ... • (&JJ ~ ···--·' '·· .... , "' . ~ -- . __ ... ··- --- . 

/ ., '· 

/" ' .. 

.,, 

I ) \_. j. 

\ ;· . / \ 

' ·,, / ,. I 

·:'·~ ., __ ... ____ -- _ .. ,,.,. ·" ... ·. (, . ,· ··- .Q. I 

·-..... ·~. 

-..... ,,,,,.. . .._ .. __________ ....... 

ROUGH 01 A.GR Al'J\ oF FRENCH 

1\./\.209 IV\ODl·FtCAl'ION 

... .--

I

'-·· H 

.=='-(' 

!' .-,=-=;-~ 

~ F 

(_.) 

0 

--rl _l_t 

-L-P 

:e,1 J 

1_j_1 

1--=u .::s= 

F134 

G~ 1\.,-. 

t 

( l;j 

-··- .... -.. ·-·--· ·-··--- ..... -·1 

~. ! 

' 

jio_ -·1 

? w 1 l . '=" > 

. <I 

' x I 

:=J::_· 

u 

() L 0 

7 

; 

4 o. 

.3: B 

2·C .. I . ,-

I !I-,~ 1::>; v 

"' . I 

· .. notch 

... ; ( '3) I ' - • - • - - - • -

~ -~ ·, .. ..__. 

., _,..I 

/ ,/ 

··--...... -

L ---· - ·----- --- ···- -- -- ··-··--- ··--···-------- ----- ··-··--·--·-·--·-----·· ·-· ------ -----·- ·-··-· 
(-...... 

\ __ ) 

--·-- --------------------- ----- ·-- --

IV• E~'T'I.IC.AL M.209 

Accoriiing to 4.rnaud1 the French are in the 

developnent Et 1ge oI' an electrically-operated 

keyboard version of the .M.209, based mainly on 

the some parts, bJ'lii de signed to work with the 

present modiliad mP-~hine. This statement is 

inconsistent vii tr tne design which we were shown, ; 

VJ hi ch is reproducod from mei-:iory on the right; it ' 

will be seen that rtgures as well as letters 

appear on t.i.ie \wheels, which must thus apparently 

have a larger cycle than the ,present L-iachinc. 

This cycle ~oula ~ppe~r ~o be 29 31 •••• 35 •• 

• T"ie lit:ie1.sions of the Lia.chine will be -- -.. 6 x 23 x $ ~:-1. it •·i11 weigh about 8 Kg·. 

18 pounds). T.JdtallS Of Voltage, etc., Ure 

ot·sc~tled. It will be capable of hand o.s 

lCll as electric~! uperutiun. It will print 

plain-l::mgnC:1.ge E.s i.~ull as a cypher tc.a.pe. 

· s at present pillm1cd, r.umbers wj.11 be printed 

as thci.c lett~r e q~i v:..lcnts; he y1j_ll ccm~i dt.:X' 

the possibility nf. including a shifting P.rintheel. He .:;J.ai&11E.d tho.t it ·;1ill 'or.:erato up 

o 4-5 chc.racters _l)<:ir s~cond. 

x 

y 

z 

3• It is clear f-L,OfJ the diagrai:, that, quite . A 

apart :from the .:£.ct that it would not even work 

with the unmodifi:3d }.i.209, no provision has B 

been rnado f vr vartabl~ alpha.bets. Arnaud did 

not make it ..:lear hovi he proposed to achieve C 

th~.s, ond it wat. i;houE ht better not to press 

hira further at" thi~ stage. \ D 

i ; 

2 

3 

z 

y 

3 

4 

5 

: J i: 

V I X I 

I 

f u i w 

I 

-: I I : ! 

u 

T 

s 

R 

Q 

p 

0 

1: 

i I J.1 . ___ .. _, 

,------. 

N 

M 

L 

K 

J 

---- ' . Q 

p 

0 

N 

M 

L 

i 

x f 

I 

; I 

·-n '----

,, Sketch fran memory of electrical key~oard machine. (Some details doubLful.) 

.. ... ,, -- ___ ,. ___________________ ·-· 

-------........... ---- --··- --· - ----·--·--~------·---

ol 

-i 

I 

I 

_j 

I 

I