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REF ID:A69983 

I.ir. .Alfred Percy 

Elon ::oad ~adison Hei~hts, ~irginia 

:ilear I.ir. f ercy: . 

424 N. George &aeon Drive ~lington, -Virginia 

15 August 1949 

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I must hasten to acknowlodge .. receipt of your most interesting 

letter of 5 August arul to indica~$ 1J17 sincere appreciation of your 

taki.."11§ the trouble to write me in ~~ch detail. 

At the moment I am much engrossed with other matters and have 

found: it necessary to put off dealina dth The Bes.le Papers. However, I do not inte~d by 8.J.I1 means to drop the study which I initiated 

on them sometime aeo. Should I have soon an opportunity t.o make a 

visit in your nei;hborhood, I hope that it will include the making 

of your personal acquaintance and discussing the matter over a dinner 

table at which I tJ"Ust that you would be sufficiently gracious to be 

my guest. · 

Thanking you again for your courtesy, I am 

SincereJ.¥·yours, 

WILLIAM F. FRima!~ 

, I 

@'pproved for Release by NSA on 04-02-2014 pursuantto E.O. 13s2a 

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~~rs. · .. artha Rivers Adams 

c/o The Newa 

Lynchburg; 7irginia 

Dear f.;rs. Ada!:s; 

REF ID:A699A1 ~· .. 

424 R. George ~a1on Drive 

Arlington; Virginia 

16 June 1949 

I sent a. letter addressed to ~r. Alfred Percy, Jr., at Elo~, 

~l.C., and then on its return by the post office I sent it to 

Elon, Va. The latter has also been returned and I, therefore, 

am writing to ask you if you cannot give ~• a more complete 

·address so that I might reach :~r. ~-ercy and ask him a few 

questions. 

I am enclosing a salt-addressed stamped envelope for your 

convenience in replying. 

With cordial greetings, I am 

Sincerely yours, 

:WILLL\.'l F. FRIF.Dr.fAN 

Incl 

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?.:r. 11e:lter B. Payne 

1be Todd Com~ 

Rochester, l!ow York 

Dea.r t:r. Payne: 

REF ID:A69w • 

Cc.rah 23, 1943 

I hopo you v:ill forgive. ?TT to.rdinoss in roplyinS to your 

letter or !~a.roh 11. I kn.cm that you "Jill undorstn.nd h0\7 

!°)ressed we aro. 

I rocall quite well that :rou had proposed a si.-:1.plo 

crJptoeraphio device at tho.ti~e or r:J/f contact with the 

Todd COn:;>&.n\Y in 1937. 

I.iy first. i!lpreasior.. r.ith ree;are to tho posoililo 

utility of a davioo such as you desoribe is that it t"1ould 

probsl.bly not bo useful bocause or its catl.p&rativ~ slawnoss 

o!' opern.tion. l!oreovor,, I 'V'Sr"J' much doub:t; that it presents 

eloncntG er novel~J in tho fiold. Howover in ordor to insure 

that wo do not ovorlool: aeythine t1mt miG}it be useful, I 

sugcost that you send the ~odel for exar.dllation and we will 

be i:;lad to make a recommende.tion. I believe it would be 

best if· you lfould address tho letter and paclcar;e oi'f'icially 

to the Commanding Officer, Signal Security Service, l'~rliD.c.,i-ton 

lia.11 Stc..tion, Arlington, Viii;inio.. Upon its receipt and 

thorour;h examination you v1ill be pronptly ir.ton:iod of our 

conclusions. 

With corclia.l grectincs to you and your s.ssooie.toa, I 8J:l 

Sincerely yours, 

rlilliam F. Friodtan 

Director of Coll..."'tlllications 

!!osearch 
e • REF ID: A6998- • 

THE TODD COMPANY 

ROCHESTER 'V NEW YORK 

March 11, 1943 

Col. William F. Friedman 

3932 Military Road 

Washington, D. c. 

Dear Col. Friedman: 

Perhaps you will recall that during your visit to Rochester in 

October 1937, when you presented your plans for a check sorting machine, you met the writer of this letter, and showed a crypto- graphic device on which you had applied for patent. On October 

13, 1938 this patent was issued, bearing No. 2,144,204. 

This cryptographic device showed two gears of unequal diameters, 

having arranged around their circunferences letters and corresponding symbols. 

Shortly after you were here, I conceived the idea of running two 

photographic film tapes over sprockets arranged side by side on 

the same shaft so that in coding a Message, letters were selected 

on one tape and corresponding symbols on the adjacent tape were 

selected to ~ake the code. It is obvious in this arrangement that 

the letters on the second tape could be scrambled in an endless 

sequence by making the tapes of a sufficient length. 

During the early part of last year, a War Research Co~mittee was 

formed in the Rochester Chamber of Commerce, of which committee 

I became a member. 

It has occurred to me that a si~ple cryptographic device might be of use in the communicationsorganizations of the Army and Navy. 

I have made a model, elaborating somewhat on my original plan, which I should be pleased to forward to you in order to get your opinion on its practicability. 

This model embodies four 16 ~m. fil.Iil sprockets fixed side by side 

on a shaft and adapted to carry four film strips. Each film strip carries a group of letters of the alphabet as shown in the accompanying sketch. In this particular instance, each group consists of five letters. Consequently, the number of permutations of each letter group could be 120; and with the four tapes the 

possible permutations would be 1204 or 2.07 x 108. 

PHOTOD-CKEF.'i'HAC .ind Sl Pt"R-S~\•"ETY CH•:cKS. l"HH ARC S\STF.i'I. DAN'K SI PPLIFS. PROrt.c1·ocR.\PllS. (.'llFCk !'tlG,•NS 
REF ID: A69983 a 

.THE TODD COMPAlW 

Col. William F. Friedman -2-2 Maroh 11, 1943 

The rows running across the four films can be brought into registrat- ion with two stationary series of letters co~prising the alphabet, figures from O to 9, and a few punctuation ~arks. The stationary letters, forty in all, may be divided into groups of five eaoh and 

the eight groups can be arranged in factorial 8 different ways amounting to 40,320. With the film tapes set in proper registration according to a known code number, and the stationary alphabet groups also arranged according to a known code number, it would be possible 

to obtain a very large number of settings which would be almost impossible to find by trial unless one could guess correctly certain 

words in the message. This would be quite a remote contingency. 

Inasmuch as the device which prompted this investigation was shown 

me by you, I think it proper to take the matter up with you before 

submitting it to the War Research Col!ll'l'littee for their considerat.ion. 

I should consider it a favor if you would give me your frank judgment 

on the merits of this device, and if you think that it is a waste of ti~e to put further effort on it, please do not hesitate to so advise 

me. The model I have made, while it is quite crude, operates well 

and you could tell by an inspection of same whether there are any possibilities tor a device of this nature. 

I have shown this model to Mr. Walter Todd and he advised me to take 

the matter up with you. which I am pleased to do as I rely i~plicitly 

on your judgment. 

Walter B. Payne 

MB 

Very truly yours 

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• -REF ID: A69983 e. a TH~ TODD COMPA~Y INTER-OFFICE CORRESPONDENCE 

DATE FROM OFFICE 

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