REF ID:A69983 424 N. George tfaeon Drive Arlington, Virginia 15 August 1949 Mr. Alfred Percy Sion 1'oad Madison Heights, Virginia Dear Mr. fercy: . : / I must hasten to acknowledge receipt of your most interesting letter of 5 August and to indicate my sincere appreciation of your taking the trouble to write me in such detail. At the moment I am much engrossed with other matters and have found it necessary to put off dealing rith The Beale Papers. How- ever, I do not intend by any means to drop the study which I initiated on them sometime ago. Should I have soon an opportunity to make a visit in your neighborhood, I hope that it will include the making of your personal acquaintance and discussing the matter over a dinner table at which I trust that you would be sufficiently gracious to be my guest. Thanking you again for your courtesy, I am Sincerely yours. WILLIAM F. FRIEDMAN / I Approved for Release bv MSA on 04-02-2014 pursuant to E.Q. 13529 REF ID: A699 && 424 R. George liason Drive Arlington/ Virginia 16 June 1949 iVIrs. .artha Rivers Adams c/o The News Lynchburg, Virginia Dear Krs. Adams: I sent a, letter addressed to Ur. Alfred Percy, Jr. , at Elon, N.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 me a more complete address so that I might reach Ur. Percy and ask him a few questions. I am enclosing a self-addressed stamped envelope for your convenience in replying. With cordial greetings, I am Sincerely yours, . Y7ILLIAM F. FRIFDfdAN Incl REF ID:A69%|$ ttareh 23, 1943 Hr, Walter 3, Payne The Todd Company Rochester, How York . Dear Hr, Payne: I hopo you will forgive ry tardinoss in replying to your letter of 1'arch 11. 1 know tliat you will understand how pressed we aro, I recall quite well that you had proposed a simple cryptographic device at tho time of my contact with the Todd Company in 1937, I.Iy first impression with regard to tho possible utility of a device such as you desorlbe is that it would probably not bo useful because of its comparative slownoss of operation. Iloroovor, I very touch doubt that it presents elements of novelty in tho field. However in ordor to insure that wo do not overlook anything tliat might be useful, I suggest that you send the model for examination and we will be glad to make a recommendation. I believe it would be best if you would address tho letter and package officially to the Commanding Officer, Signal Socurity Service, Arlington Ball Station, Arlington, Virginia. Upon its receipt and thorough examination you will be promptly informed of our conclusions. With cordial greetings to you and your associates, 1 am Sincerely yours. \ William F. Friodman Direotor of Communications Research 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 circumferences letters and cor- responding 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 make 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 Committee was formed in the Rochester Chamber of Commerce, of which committee I became a member. It has occurred to me that a simple cryptographic device might be of use in the communicat ion?- organizations 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 mm. film 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 ac- companying sketch. In this particular instance, each group con- sists 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 120^ or 2.07 x 10 8 * PROTOD'CKEENII AC unci St PFR-SAFETY CHECKS • V H K ABC St STEM • BANK SI PPL1FS • PR O T ECTOC K A I'll S • CHECK S 1 V. \ h K S REF ID : A6 9 983 ^ Th't iuuu CJUMPAIW Col, William F. Friedman -2-2 Mar oh 11, 1943 The rows running across the four films can be brought into registrat- ion with two stationary series of letters comprising the alphabet, figures from 0 to 9, and a few punctuation marks. The stationary letters, forty in all, may be divided into groups of five each 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 im- possible 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 Committee for their consideration. 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 time 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 for 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 implicitly on your judgment. Very truly yours Chief Designer ' Walter B. Payne MB ^ ^REF ID : A69983 Q. ^ TH* TODD COMPAm Inter-Office Correspondence "?w// £?<« TO DATE FROM OFFICE AT ATTENTION OF -■ ” SUBJECT 1 ■ ANSWERING YOURS OF DICTATED BY I." EVERY INTEROFFICE LETTER MUST HAVE A SUBJECT. WRITE OF ONLY ONE SUBJECT IN THIS LETTER. NO faAt I fTATiON OR SIGNATURE IS NECESSARY OR DESIRED. ^ y ■ ; nm - i yn l ■ ■ ^ — — I ■■ M , - . ' f 7 f to in a ussmpG Pot sahg as /a skeftbh