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GEORGE rABYAN 

CHICAGO 

'CiJ P'( 

- p O.BOX 435 

Dear General Churchill: 

I played hooky from business yesterday and went 

carefully over the events of the week end with the different individuals. 

I was disgusted to ascertain that Major Yardley did 

not go into the decipherment of the A. T. & T. Cipher Yachine to the extent which I had arranged and which I thought he he.d when he told me he 

understood it and could do it. 

He seemed to think that we possessed more information than we should and with this information there was no reason why we 

should not decipher anything. I cannot agree with him on this. The time 

he spent with Friedman was evidently spent on personalities and giving 

Friedman the information on the correspondence between Riverbank and the 

M. I. D. 1 including the fact that I had requested the M. I. D. to withdraw 

the offer they made to the Friedmans, eto. 

If the Signal Corps has an Officer who is conversant with the me.chine and has a fundamental knowledge of deciphering, I 

would like to have him sent to Riverbank with instructions to investigate 

the work we have done and make a report on it, provided this meets with . 

your approval. If this is done, I would like to transmit to you the leather folder which you looked at on my desk in Geneva for your files in 

which can be inserted the report of the Investigating Officer, making it 

complete. 

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

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At the risk_ of being considered verbose, I ca'l'l;not resist the 

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temptation of placing this matter before you, the same as I, tried to put 

you into possession or some or the myst,ries or other. ciphers''while you 

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were at Riverbank. There is nothing of the ocuit can,enter into this 

work because I do not understand the ooult and I do not think you do. 

The A. T. & T. Cipher Machine, to my mind, is constructed 

- along the same principles as the automatic player which is operated by 

a role of perforated paper, perhaps on your awn pian~ at home, with the 

exception that the piano player is operated by air and the A. T. & T. 

Machine by electricity. In one case the perforations permit the passage 

of air and the blanks prevent it. In the other case the perforations admit of electrical contact which the blanks prevent. 

My understanding is that these machines are used by the A.T. 

& T. Company in all of the larger offices throughout the country in place 

of a telegraph ~ for the purpose of sending information in plain text 

in reference to settin~ up long distance calls and otherwise. Accident, 

by connecting up the wrong poles, gave a lot of random letters and when 

the local machine was connected by changing the poles,the lot of random 

letters were transcribed by the ~ypewriter to represent plain text. From 

this phenomena, the present cipher method was developed and, in my opinion, 

any one interested, could get all the information concerning it. 

The method of deciphering calls for a little different mechanical knowledge than the method for encipherment and I believe it will 

be of value to both the M. I. D. and the Signal Corps and will relieve me 

of the possession of papers I do not care to have. I suggested a Signal 
REF ID:A419B74 

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Corps Officer merely because it is necessary to have someone who is conversant with the ma.chine. You will, of course ,understand that anyone you 

choose to send will be welcome. If it is deemed wise to do so, I should 

-- be happy to have a set of the machines expressed to Riverbank with the 

view of making their work more difficult of decipherment should the Department care to do this. 

Another,heretofore indecipherable cipher,was broken yesterday. 

It doesn't happen every day, but it's a lot of satisfaction when it does 

happen. 

With assurances of my personal esteem and regard, 

To General M. Qhurohill, 

Woodward Apartment, 

2301 Connecticut Ave., 

Washington, D. C. 

Sincerely yours,