REF ID:A39603 

• 

Brief' Description ot a Crn>tosraph1o :Machine Bm.plo7ing a SiJ:lgle Cipher Ccmmmtator -- -

B.1 • *· F. Friedman 

l. Thia invention dee.la with a cryptographic machine in which the ol'JP"tographio 

principle is basicall3 as follows: 

Power is delivered to the ke7board at the enciphering position at a specific instant in a period of 26 possible 1natanta, the cipher resultant of a given plaintext letter dependins therefore upon the specific instant the keJ"board is made 

"alive", since for ea.oh of the 26 different 1natants a different mixed cipher alp:babet is presented for enoipberment. 'l'he order of presentation of cipher alphabets is regular but the e:x:act instant of the selection of a specific cipher alphabet is V&rJ' irregular and depends upon a keying factor. 

2. The machine consists basicall.J' of a sinale, constantly rotating, 26 segment, 

26 character cipher OODlllLltator, labeled 1 in Fisure #1, controlled by a ke71ng 

s7stem. including a set of rotatable, differential cam wheels or an equivalent electrical cam arrangement. Thie control system canprisea 5 or a mu.ltiple of 5 

cam wheels which operate contact levers, shown at 2. 'l'he inter-action of the 5 

contact levers results in eettiDS up at the 5 relays, 3, 4, 51 6, 7, a permu.tation 

in the Bordeaux code. Oorrespondiug to this permutation there is set up a permutation of 5 translater bars, labeled 8, 91 101 11, 12. These are slotted 1118111.bers 

&Dd when a specific per.mutation is set up, ODe of 32 stunt bars falls into place 

am closes a contact. Several of these contacts are shown in the sketch at 1'· 

These circuits lead to a switchboard 14, on one side of wh1oh there are 32 positions am on the other side of Which there are on]1' 26 positions. Referrins to 

the cam.wheels these are of different diameter am ot different zmmbera ot interwls,, pref'erab]J' all prime to one another. Th.e7 are illdividual]J' rotatable in 

step-wise manner, under control of' thekeJboard. The potential cipher ke7 which 

results from such an arransem.ent is in length the product of the individual interval numbers of the several cam wheels. For e:mmple, if there are 5 cam wheels 

the f'irst of 100 intervals, the second of 99, the third ot 971 the fourth of 91 

am the fifth of' 89 intervals, the total length of the cipher ke7 would be 

71777 ,469, 700. Thia :mere]3' :means that the cipher ke7 would consist of an unintelligible sequence of cipherins ke7 ol:laracters of corresponding length. 

'· The '2 possible resultant Bordeaux pel'JIDltations which are led to switchboard 

14 are for the parposea of' this invention reduced to 26 bJ consolidatins 6 of 

the 32 o1rcU1ta into the other 26, so that there will be o~ 26 ditf'erent resultant effects 'far oyptographic ke7ins purposes. In this invention this is accomplished quite a1m.pl;r bJ tald.ns what are usual]3 known aa the 6 extra functions 

and tbrowins them in with 6 of the other 26 letter-representing Bordeaux permutations. Which 6 will be selected to be "double-representations" can be deter-

. mined am varied at will at the switchboard 14. 

pproved for Release by NSA on 10-09-2013 pursuant to E. 0. 
REF ID:A39603 

.. • • 

4. In this invention the 26 specific effects thus rendered possible 'bJ' cam 

action merel;r detem.ine which one of 26 segments w.111 be DBde "alive" (that 

is, will be connected to a power source) on a set ot 26 aesmenta in the distributor head 1.5, over which brush J.6 sweeps in 81J1ohronismwith comamtator 

Wheel #1. As shown in the figure 1 this action mere]1' means- that at a given 

instant rela7 17 is energized, the :lmtant ot energization beiDg controlled 

b7 the cam arraJ:l8Elll,ent and will be different for each k87 operation at the 

kqboard. 

5. When a specific segment of the distributor 15 is made "alive" b7 be1DS 

connected to a power source 1 and when the bru.ah arm 16 reaches this llve segment, the lm7board of' the cr.rptosrapb is •de "alive" at that instant b7 the 

completion of the circuit from. power source lB at contact 19. If a ke7 is 

depressed durilJg that c7cle1 the· letter corresponding to that ke7 will be enciphered in the specific c1pber alpbet detem:l.ned b7 the speo11'1c ansular 

position of the cipher commutator fl at the instant that the brush arm. J6 

reaches the live sesment on distributor 15. In other words, the ke7board is 

made "alive" at l of 26 different instants 111 the cycle passed tbrougb b7 the 

C01111Lutator wheel; each of these inatants corresponds to a different mixed 

alphabet of which there is a total of 26. It is to be understood tba t tb.e 

cam wheel assemb.q is set at an initial keying position b7 pre-arransement 

and that the cams advance one step or interval per depression of the keyboard 

and no more. 

6. The cipher cOJ1111Utator ~ be made a rec1prooal cipher oomutator; or by 

suitable switching arransements a nonreciprocal encipher1ng-dec1pherilJs relationahip DJA7 be provided for, if desired. 

7. The ke7board 20 is connected to the lefthand bakeli te separator 21, and 

the circuits pass from 21 throush cipher commu.tator #1 to the rightballd. bakellte separator 22 and thence to the bank of' indicating devices 2}1 back to 

power source lB. 

8. Means and circuits 111WJt be provided to prevent the c17ptosraph from recording or indicating a resultant more tban onoe for the same set up of keys 1 so 

tbat there DJA7 be one and on.q one cipher equivalent per keyins ope:ration. 

9. Instead of a set of 6 t:ranslater bars and '2 stunt bars an arralJ88l119nt ot 

llllll.tiple contact relqs as shown in Figure {/e at 24 may be provided if deemsd 

more practicable tlan translater bars. 

10. For decipherment, hav1ns a reciprocal ciphering co.mm:uta.tor the key settinS 

of the cam Wheels being the same as the initial settins at the encipher1ns end 

the sequence of ke71DS characters would be identical at the decipherinS end 

and the reciprocity between plain-text and cipher characters is established 

thrOQSb the cipher commutator and the decipherment is effected in a simple 

mzmer, that is, it at enoipherment at a given instant A equals 1t then in 

decipherment at that homologous instant (with respect to the cipher key) IC 

would be deciphered ae A. 
••• ..:r_ • 

) 1,. , : . .... 

. ' 

.. 

' . 

! ; 

\. 

-

., ~ . . 

• 

REF ID:A39603 

·Wi. 

i i , 

. l 

I ; . 

Jl. ,,, 11' Ir w 

1'tL--------. 

L.·:~·-·- -~·-·-.:.:. 

- -- - - - ~~ -- - - ~ - - - - -