/ •• l' 

REF ID:A4148Bji 

,.._, 

WAR DEPARTMENT .:on 

HEADQUARTERS CENTRAL DEPARTMENT 

CHICAGO ' -I 

'If ?Jf-5-~ 

August 18, 1919. ~ v-f 

'v,k,\ c:.~i.;.~TMENT 

General Marlborough Churchill. 

MY dear General: 

You will find enclosed letter from Colonel Fabya.n 

concerning SundQ¥'s ~onferenoe at Riverbank. Enclosure is self-explanatory and I can say but little in addition thereto which will 

add to your enlightenment. 

I fail to understand why the Colonel arrived at 

the conclusion that I was there present as your representative, in 

fact, I most distinctly stated to him that I had no official interest in the conference, but was merely an interested spectator. The 

Colonel apparently views me in the light of a sympathetic friend in 

whom he may confide his numerous grievances and misunderstandings. 

The Colonel appears to have little confidence in 

Colonel Mauborgne's sincerity of purpose and he (Colonel Fabyan) 

stated to me, at the conclusion of Sunday's conference, that he felt 

convinced that Colonel Mauborgne was not a seeker after truth, but 

was mainly interested in justifying his assertion to the War Department that the A. T. & T. code as used by the Signal Corps was invulnerable. Colonel Fa.byan further stated he suspected that in future 

investigations Colonel Mauborgne would not ,"play fair" and supply him, 

for test purposes, with current work, but would endeavor to entrap the 

Riverbank Laboratories for the purpose of gaining from them the verification of his assertions to his superiors. 

I ha~ a conversation with the Colonel this morning 

and am of the impression I left him in a much better frame of mind 

a.nd with a desire to continue the work in hand. The Colonel requested me to call upon you for a personal assurance that there would be 

no puzzles or trick codes submitted to him for this work, if it is 

the desire of your department that Riverbank should continue its 

labors. 

I. most respectfully suggest that a letter of appreciation will not be remiss. The Colonel is possessed of the vanity 

of a debutante and a little catering to that weakness would unquestionably record results. 

:Most sincerely, --~~---,...,....-=.....,..~~....-................ ~___,...,......,.........,..,,.........,..-~~~---

pp roved for Release by NSA on 11-18-2014 pursuant to · 

.0. 13526 T. B. 

P. s. I have just ~ is momen received a telephone message fr m Col. 

Fa.bya.n in which he states that from data left with him yesterday by Col. 

Mauborgne he is prepared now to state that he can break the code in question. 

To Bo C. 
REF ID:A414BBii1 ...... 

Dear General Churchill: 

In reply to your letter of the 15th inst. in reference 

to the A. T. & T~ Com~ cipher and the opinion expressed on Ma.rah 27th by 

Riverbank that this system was not invulnerable. 

I:_ Col. Mauborgne and MaJor Yardley were here last Sunday and we went 

over the entire matter, giving them eaoh a oopy ot the leather bound briefs 

and charts explaining the method of attack on the cipher as formerly used by 

the Department.] : , , · ~ 

- · lCol. Mauborgne took particular pains to assure us of our error in 

regard t&-\vhat he was pleased to call our assumption as to the manner in . 

Whioh th~s·machine was use~and I beg to.su~it tor your information the 

attached oopy ot MaJor Fowler~s letter to me. I am reliably informed that 

he was the officer in charge ot this system during the war. When we were 

desperate he was invited to come to Riverbank tor the purpose of determining 

whether or not our information in reference to the use of the cipher machine 

was correct. Major Fowler, on his own initiative, made a report to the Chief 

Signal Officer and I attach a copy of Lt. Col • .Paddock's reply to MaJor . Fowler, for your information •.. I also attach an extract ot the c.onversation 

taken in shorthand ·at Riverbank. We--are not 'informed as to Col. Mauborgne' s 

purpose in taking the position he did but assume it will be evidenced by hie 

. """·~epo~t to ·the Ch~ef Signal Officer. [! was most favorably, impressed by Ma.Jor 

Yardley's alert mind in following the oonversation as it applied to the 

oipher, and believe that on a careful reading of the briefs and studying the 

charts he will know as muoh about it as we do~ 

[901. :rJauborgne left· wi'th us a rough pencll sketch of the manner in 

Which the machine 1e ~used, reiterat~ng his o,pinlon that as ~used, the 

9ipher ie invulnerable. This, in spite ot the admission that neither he nor 

Major Yardle~-have made any attempt to decipher the work of this maohlne. A 

copy of this rough pencir·dratt is enclosed. Col. Mauborgne said further that 

if we oould break the cipher when used in accordance with these rules he would ._ 

then acknowledge that we had broken the cipher as used by the Signal Oorp1. 

We are sending yalltoday a chart and the brief showing that this modified 

method of using the machine does not make the cipher invulnerable. If a?cy"thing, 

it is more easily broken and we recommend that the cha.rt and the brief be handed 

to Major Yardley and explained to Col. Mauborgne in order to save further 

expense in thl& direct1o1!J In taot, we would be happy, under the clrcumstanoes, to have this come from the M. I. a to the Signal Corps. 

We regretted that neither Col. Mauborgne nor Ma.Jor Yardley, and 

particularly the latter, could remain long enough at Riverbank to understand 

tully the principles of the decipherment of this system. And it la respectfully suggested that inasmuch as this is a Signal Corps matter, we would 

particularly like to have Lt. Col. 2addock detailed here long enough to be 

instruoted in referenoe to the system of attack and decipherment, Which would 

also give us the opportunity ot disabusing hie mind of any preconceived 

ideas which he h&s expressed in ret~rence to the wo~rk being done here. 

sinoerely yours, ' 

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