T '" 

() REF ID:A67509 

The object of this invention is to provide new and useful improvements in cipher machines or cryptographic mechanisms utilizing rotatable· 

COlIIIllutators for enciphering a plain-language message by what is commonly 

-known a~ a proc.ess of substitution, the latter being accomplished in a 

systematic manner so that the process of substitution may be automatically 

reversed in deciphering such an enciphered message, thu.s recovering the 

original plain-language message. 

In the. cryptographic mechanisms ref erred to there is usually _provided 

a keyboard of the typewriter type, which controls a set of switches 

corresponding to message characters, and a set of signaling devices which 

may consist of a bank of glow lamps or magnets to indicate the message 

characters resulting from operation of the keyboard. The set of switches 

of the keyboard and the set of signaling or indicating devices are connected 

ta each other electrically by c.ircui ts and·' apparatus by means of which the 

aforesaid substitution is accomplished. 

The cryptographic principle of such cryptogra9hic mechanisms, which 

will hereinafter be termed simply· cryptographs, is based on the establishment of a plurality of electrical circuits or'paths between the keyboard 

switches and the indicating devices through commutators of a. special type 

now well known in the art. These commutators are constructed in the form 

·of flat disks bearing an annular set of contacts on .each face, individual 

contacts of one face being connected by insulated conductors passing through 

' the disk to individual contacts of thE;J other face in an arbitrar; manner. 

·In the literature of cryptography such commutators are called "cipher wheels", 

"coding cylinders", and the like; but, for purposes of greater clarity in 

description they will hereinafter be referred to as 11 substitution com.~utators." 

In a single cryptograph there may be several such commutators juxtaposed on 

a common shaft. Thus, when more than one substitution commutator is used, 

the cipher letter obtained upon depressing a key of the keyboard is the result 

of the passage of an electrical current along a complex path set up through 

_all the juxtaposed su?stitu~ion commutators, this path being composed of as 

many sub-paths joined sequentially as there are commutators. 

@'pproved for Release by NSA on 09-09-2013 pursuant to E.O. 1352EI 

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REF ID:A67509 

Cryptographs of the foregoing description may be divided into two 

categories. Into one category may be placed all cryptographs having one or 

more substitution commutators. rotatably mounted on a shaft between two fixed 

end plates, each end plate bearing an annular ring of contacts, the latter 

being so disposed as to coincide exactly with the contacts on the faces 'or the 

substitution commut._ators. In ci-Jptographs falling into this category the keying 

switches of the manually operated keyboard are connected tp the contacts of one 

of the end plates, whi~e members of the bank of indicating devices are connected 

of twice as m&DY contacts as there a.re keys on the keyboard 

to the contacts of ~u .. other end plate. Also a reversing switch/is provided, 

which enables the operator to interchange the connections between the two end 

plates, the bank of indicating devices and the keyboard switches so as to provide for enciphering and deciphering equivalency. Into the other category may 

be placed all cryptographs having a single end plate of the type described. 

The latter contacts are, however, connected to the movable members of a set 

of single pole, double throw svvitches, the number of switches being the same 

as the number of contacts provided on the end plate, and so constructed that 

the switches are controlled by the keys of the manually operated keyboard. 

Adjacent to the above-described end plat€ are.mounted one or more substitution 

coI11~utators, the final commutator, that is, the one most remote from the end 

· plate, being what is hereinafter described and referred to as a 11 reversing 

commutatorn. The purpose of the reversing commutator is to return a current 

entering the commutators at one contact on the' end plate ta some other contact 

thus comes 

on the sa.i'lle end plate; '_,he current 'J'Elfing into the reversing plate via one 

returns 

complicated path throilgh the cc . .imutators and.~ t~ the end plate along 

another path through the commutators. Thus, in this category of cryptographs 

enciphering-deciphering equivalency is effected without the use of a reversing 

switch which is necessary in cryptogra9hs of the first category. 

In both categories of cryptographs it is usual to provide means for angularly 

displacing or rotating the commutators, the reason for which will be briefly 

discussed. If, in cryptographs utilizing substitution commutators of the type 

described, no provision is made for their angular displacement during the course 

.of enciphering a plain-text message, the resulting cipher text will be monoalphabetic in character; that is, only one substit~tion alphabet will have been 
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() REF ID:A67509 ~­

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used in the entire encipherment. It is a well-known fact th~t such 

monoalphabetic cryptograms offer little resistance to _cryptanalysis, 

and1 in order to ·increase the cryptographic security of such CI"Jptograms, 

factors other than mere change of alignment of the substitution corn.mutators 

·from message to message must be incorporated therein. Heretofore several 

types of cipher machines have been invented in which one or more of the 

substitution commutators are rotated step by ste_p with the encipherment 

or decipherment· of each letter, but in a regular and/or meter-like manner. 

Such cipher machines provide a considerable increase in cryptographic security 

(that is, resistance to cryptanalysis) over those cipher machines in which 

no angular displacement of the substitution com.mutators -takes place, but still 

not sufficient to insure practical indecryptability for cryptograms produced 

by their use. This is because the latitude-uf variability .offered by the 

substitution commutator displacement mechanism is limited and all forms 

thereof may be readily reconstructed from a model of the cipher I1U1chine. 

It is the object of this _invention to provide a means of effecting the 

. ' ' 

angular displacement or rotation of the substitution commutators in an 

irregular, completely aperiodic manner, thereby greatly increasing the resistance to cryptanalysis of CI"'Jptograms encipher_ed by cryptographs of the· type 

described. 

A basic feature of the invention is the provision of methods and means 

for controlling the angular displacements or~ the substitution commutators 

·by electrical circuits which_ also pass throue;h rotatable commutators. The 

latter thus constitute, in effect, commutators for the control of the 

substitution commutators; for sake of brevity and clarity in description, 

commutators performing this function of controlling substitution commutators 

will hereinafter be designated simply as ''control c.ommutators". Several 

specific embodiments of the basic invention will be described. At this point 

it will merely be mentioned that the control commutators may form an independent unit physically separate from the substitution commutators but 

e~ectrically associated with t,he latter; it is possible, however, to make 

one and the same set of com.~utators serve both as control commutators and 

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: ) ··~. 

substitution comm~tators, there being provided associated means designed to 

keep the control functions electrically separate from the substitution functions'. 

The several different embodiments of the invention Qnd the modes of 

operation of the various forms are explained in this specification in detail 

sufficient for comprehension by those skilled in the art·. ThE' explanation is 

made in connection with the accompanying drawings, Figs. 1 - 6. 

Fig. 1 is a schematic diagram of the simplest embodiment in which there 

is shown a first set of commutators for performing substitution functions qnd 

a second set of som~Nhat differently constructed commutators for performing 

control functions, together with the associated circuits and contacts for 

proper operation of the cr-fptograph. Fig. 2 is a schematic diagram of a set 

of commutators also designed for performing control functions but in this 

case these commutators are similar in construction to the substitution commutators. Fig. 3 is a schematic diagram of another embodiment in which a single 

set of double-ring commutators of novel construction performs both functions 

of substitution and control. Fig. 4 shm\'S a front and side elevation of one 

of these double-ring commutators. Fig. 5 is A. schematic diagram of another 

embodiment in which a '**~hi set or double~ring commutators is arranged with 

associated switching mechanism so as to perform both functions of sub3titution 

1 to 4, inclusive, are substitution commutators of the normal type hereinbe:JrA 

described, in which there is a single ring of 26 contacts on each face, the 

contacts on one face being connected irregularly to the cont~cts on the other 

face. Commutator 5 is also a substitution commutator, >Jut differs from the 

others in that only one face of the commutator bears a ring of contacts, the 

latter contacts being interconnected irregularly in pairs. A current entering 

one contact of the single ring of contacts is merely carried along on insulated 

conductor to some other contact, from which it emerg.es from the commutator. In 

other words the current enters the commutator at one contact and leaves it at 

another, on the same face of the commutator. This is a commutator of the type 

referred to above as a reversing commutator. Commutators 6, 7 and 8 are control 

commutators of which 7 and 8 are similar in principle to substitution commutators 1 to 4, except that they have only six contacts instead of 26 in a ring - 4 -
0 REF ID:A.675090 

on each face; commutator 6 is a reversing commutator and is similar in principle 

to reversing commutator 5, except that it has only six contacts instead of 26. 

The substitution commutators are mounted upon a common shaft 20 upon whieh 

they may be. independently angularly displ~ced stepwise 1/26 of a revolution, 

bearlng plate 302, the latter 

between fixed end plate: JOl aaj/~ serving merely as a retaining 

plate and havi~ no contacts or conductors within it. The commutators are· 

separated by fixed plates .305, .306, 307, and 308 which bear rings of 26 contacts 

suitably dispose4 for bridging between successive com.mutators, in order to ' . 

·provide for electrical continuity from one commutator to its next adjacent one. 

The contacts in these separator plates are ball-bearing spring contacts exerting 

sufficient outward pressure to insure good contact. The control commutators 

are mounted upon the same common shaft 20 upon which they may likewise be an-

. gularly. displaced stepwise 1/6 of a revolution, between fixed. end plate 3~ 

bearing plate .30.3, the latter· . ·

0 

. • . 

an.9/n•p•·•·'X?·hkrtjC@ serving merely as a retaining plate. 309 and 310 are . . . 

separators similar in construction and function to separators 305 to JOS, 

except that they have rings of but 6 contacts. The motion of the three control 

commutators, is ·meter-like, commutator 8 being moved 1/6 of a revolution for 

each. character.ciphered, commutator 7 being. ~oved 1/6 of a·revolution per complete revolution of commutators,· and commutator.6 bei:ng moved i/6 of a :i;-evolution.per complete revolution of commutator 7. This set of three commutators 

has a com~lete period (return to an :iJiitial position) of 216; that is, after 

216 characters have been enciphered or deciphered the commutators return to 

their initial relative rotatory positions. The means for moving these coinmutators·will be described presently. 9, 10, 11, 12, and 13 are magnets, here 

termed substitution-com.mutator selector magnets, which. when energized, determine which of the substitution com.mutators 1, 2, 3, 4 and 5 are angularly 

displaced, either by acting directly on ~he commutators or by releasing an 

.actuating mechanism which acts directly on the commutators. 14 and 15 are 

two of a set of twenty-six indicating devices such as glow lamps or magnets 

for operating a printing mechanism, such indicating devices being well. known 

. in the art. Ea.ch indicating device corresponds to a letter of the. English 

alphabet. 18 and 19 are two of a set of twenty-six single-pole, double-throw 

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REF ID:A67509 i ' 

\,-') 

switch levers. operated by the keys of a typewriter keyboard. The keyboard 

is also provided with a universal bar 44, which controls switch lever 17, 

the functions of which will be described later, and it also controls switch 

lever 117 and contact 45, which control magnet 31, the latter serving to 

displace cozwnutator 8 one step per depression of any key of the keyboard. 

When commutator 8 makes a complete revolution, it closes contact 32 which 

controls magnet 33, the latter serving to displace commutator 7 one step 

per 6 depressions of keys on the keyboard. When commutator 7 makes a complete 

revolution it closes contact 34 which controls magnet 35, the latter serving 

to'displace commutator 6 one step per 36 depressions of the keys of the keyboard. Contacts 32 and 34 are operated by rollers on spring levers. These 

rollers normally ride upon the peripheries of commutators 7 and 8, but at a 

certain point on each commutator there is a transverse slot which allows the 

roller to drop sufficiently to close the contact concerned. Of course·, these 

three commutators could be displaced mechanically, by means of ratchets and 

pawls and direct control from the universal bar of the keyboard. To the right 

in Fig. 1 is shown a side elevation of fixed end plate 304 which adjoins 

control commutator 8 on the exit face of the commutator. The whole lines 

show the conductors leading away from the 6 contacts on the right side of the 

the dotted lines show the conductors leading from the left side of end plate 304 

end plate 304,;'Lnto commutator 8. 

Having now particular reference to Figure ·1 with a view to giving a 

complete description of the action of this form of the invention, the sequence 

of events which transpire during the encipherment of the plain-text letteISwill 

be related in detail. In ~rder to encipher a message, it is necessary first to 

mount the commutators upon the shaft according to some prearranged order, it 

being obvious that commutators 1, 2, 3, and 4 may be interchanged in position 

amongst themselves, and commutators 7 and 8 may be interchanged; commutators 

5 and 6 must remainin the positions shown, since they are reversing commutators 

and cannot be replaced b"/ the other com.~utators or by each other. Next it is 

necessary to align the several commutators, as regards their relative rotatory 

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REF ID:A67509 ( ~-""""' \ 

'. ) ·~ 

positions upon the shaft, a~cording to a prearranged key. After all this 

main power 

has been accomplished.:.fs.7itch 36 is closed, setting up a circuit as follo~s: 

· · cl,osed conductor 51 

From battery 16 ta/srvitcli 3l2.&/contact lever 17, closed c.ontact ·21, conductor 

26, -Conta.ct 27 on the fixed end plate 304, into, through, and out of the 

·control commutator unit via the route through 8, 310, 7, 309., 6, 309, 7, 3io~ 

i5Qt8 as indicated to contact 28, thence along conductor 38 to selector Il!L~aet 

10, conductor ·43 and bacl~ to battery 16. When magnet 10 is momentarily energized 

it causes substitution commutator 4 to be ·displaced angularly t:h.rough l/26th 

of a revolution. The machine is now ready for enciphering. If the letter A is· 

to be enciphered, the key. corresponding thereto is depressed. At the beginning 

of its downward travel the universal bar 44 causes contact lever 17 to move away 

from contact 21. The key bar A causes contact lever 18 to break contact at 46 

and to make contact at 22, setting up a circuit as follows: From battery 16 ~ 

closed 

along conductor 23 t2fcontact 22, contact lever 18 an~ conductor 24 to a contact 

29 in end plate 301, thence into substitution commutator 1, through the commutators and separators.l, 305, 2, 306, 3, 307, 4, 308~into and out of reversing 

commutator 5, back ~hrough separ~tors and comm~tators 308, 4, 307, 3, 306,. 2, 

305, 1, out at contact JO, return along conductor 25 to contact lever 19, · 

oontact 47, thence to indicating device 14, which in this drawing corresponds 

to the letter Q, conductor 43, and back to battery 16. At the end of the 

downward travel of the universal bar 44, the latter moves switch lever 117 and 

"' closes contact 45, momentarily closing the circuit for energizing magnet 31. 

This causes control commutc.tor 8 to be anQllarly disIJlc.ce~ through 1/6 of e_ 

. revolution •. When key A is reler..sed, the univers-:-_l bc..r 44 is retur:u.cd t'.) its 

normc.l position by a retrc.ctile spring .s.nd contPct lever 17 return:.; to contc..ct 

21, reestablishing the circuit from b~ttery 16, .~Nitch 36, lever 17, cont~ct 21, 

conductor 26 to contact 27 of fixed enc. l'.)b.+c 304.~ ·,Due to the angular 

·' · the current will now 

displacement of control commutator 8..J~ traverse a new path through the 

control unit and back to some other contact of end plate 304 from whence it 

passes through one of the selector magnets 9 - 13, to battery 16, causing one 

of-the substitution commutators to be displaced, and thus providing a new 

substitution alphabet for the encipherment of the next plain-text letter. 

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REF ID: A67 50 9 (~--". l 

0 

The deciphering operation of this machine is the same as the enciphering 

operation, the enciphering-deciphering relationship being by nature reciprocal. 

In setting the machine for deciphering, the same procedure is followed as for 

enciphering; that is, the commutators are arranged and aligned at the bench 

mark according to the prearranged key and switch 36 is closed, whereupon substitution commutator 4 is angularly displaced as hereinbefore described. The 

ke}r correspondine to the cipher letter Q is depressed, which causes contact 

lever 19 to bree.k contact at 47 and to make contact at 42 causing current to 

Qiosed contact 42, 

flow from battery 16 through conductor 23.a/contact lever 19 and conductor 25 

to contact 30 on end plate 301 of the substitution commutator unit. The current 

passes into and through the latter along one path and returns along another 

path as described before; it emerges at contact 29 on end plate 301 and flows 

along conductor 24 to contact lever 18, closed contact 46, to indicating device 

15, which corresponds to the letter A. The \llliversal bar 44, operated by the 

depression of the key corresponding to the letter Q, closes contact 45 at the 

end of its downward travel and causes control commutator 8 to advance. When 

the key corresponding to the letter Q is released, the universal bar 44 

returns to its normal position, causing contact lever 17 to reestablish contact 

at 21 thereupon causing a substitution commutator to move forward, as described. 

In Fig. 1 the control commutators were provided with rings of but six 

contact surfaces on ~ach face, whereas the substitution commutators were provided with rings of 26 contact surfaces. There is, however, no reason why 

the substitution and the control commutators should not be identical in this 

regard, thus providing for their interchangability and grel!tly increasing 

the keying possibilities .of the cryptograph. 

In Fig. 2 is shown.how the homologous elements of Fig.-1 may be modified 

to accomplish this effect. End plate ~04 and the commutators 6, 7, 8 now 

bear rings of 26 contacts instead of rings of only 6 contacts. Contact 27 

remains a single contact for the entrance of the current into the control 

commutators, leaving 25 contacts on end plate 304 for the emergence of the 

current from the control commutators. These 25 contacts are then joined in 

5 sets of 5 contacts each, to the five conductors 37, 38, 39, 40 and 41. 

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i. 

i ! . 

·----~----- --- - -

REF ID: A67509 / .() · \_,. 

Other groupings in respect to the numbers and identities of contacts constituting each of the five groups may be preferable, or this may be subject 

to variation, according to a key. 

The arrangement shown in Fig. 2 provides a sequence of keying impulses 

which will not begin to repeat until control com.~utator.6 has made a complete 

revolution, or after 26 x 26 x 26 = 17,576 depressions of the universal bar, 

corresponding to the encipherment of exactly 17,576 letters of plain-text. 

Due to the irregular manner in which the internal connections of the control 

commutators are made, the substitution commutators will be caused to rotate 

through unequal angles, so that when the second cycle of the control commutator 

unit is begun, the alignment of the substitution commutators will differ from 

its initial alignment. As a consequence of this new alignment of the substitution commutations, the period of the sequence of selection of substitution 

alphabets_ will be greater than 17,576 by some multiple of that number, depending 

upon the wirine of the three control corwnutators and the manner in which the 

contacts of end plate 304 are connected to the selector magnets. This substitution period is theref'ore one of tremendous length. 

A third form of the invention is schematically depicted in Figure J. From 

a cryptographic standpoint the essential difference between this form and the 

first described form lies in the utilization of a single commutator unit, which 

serves both as a substitution commutator unit and as a coptrol commutator unit, 

the two functions being performed by independent, concentric rin~s of contacts 

borne on the same commutators. In Fig. 4 there is shown a side view of one 

such commut~tor. In this figure there is on each face of the coTIL~utator an 

for the sake of clarity, 

outer ring of 26 equidistant conte.cts_, of whicl!J'only six· indicated by numeral 

48 are shown, and a concentric·inner ring also of 26 equidistant contacts, -Oif. 

which only six indicated by numeral 49.are shown. The contacts 48 of the outer 

ring on one face a.re irregulnrly connected by insulated conductors 50 to the 

contacts 14.3 of the outer ring on the other face. S_imilarly the contacts 49 

of the inner rine; on one face are irregularly connected by insulated conductors 

150 to the contacts 149 of the inner ring on the other face of the commutator. 

The two rings are therefore entirely independent of each other, though they 

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. l'-._) 

REF ID:A67509 

are both carrieq on the same colllll.U.tator. Commutators of this type will 

· hereiJJatter be termed double-ring commutators. 

Reference is now made to Fig. 3 in which this embodiment of the invention 

is also shown merely in schematic form •. 101, 102, 10.3, 104 and 105 are doubler~ Commutators mounted OD a Common Shaft 20, separated by separators 305, 306, 

307, and 308. Means are provided to cause the commutators to be closely pressed 

against one· another so that positive electrical contact may be ma.de between 

adjoining commutators and separators and betw.een commutator 101 and end plate 

301. A side elevation of end plate 301 is depicted at the left in Figure 3, 

showing the connections between the contacts thereon and the selector magnets.9' 

10, ll, 12, and 13. Th~ dotted liJie through the commutators 101 to 105 indicates 

the path of the current through t,he inner rings of contacts while the continuous 

line marks the path through the outer ring of contacts. 

The sequence of events during the encipherment of a letter is as follows: 

When main switch 36 is closed, at the ca1111en~ent of operation, a circuit is set 

up as follows: From battery 16 through close4 main switch 36, conductor 51, con-

~ct lever 17; contact lever 17, closed contact 21, conductor 26, inner-ring 

contact 1~7 of end pl.ate 301, into.commutators 101to105 and out of them along 

broken-line path to another inner-ring contact 128 or·end·plate 301, thence 

along conductor 38, through selector magnet 10, along conductor 43, back to . . . 

· batte1'1 16. When selector magnet 10 is momentarily energized it causes com-

~tator 104 to be angularly displaced 1/26 of a revolution, thus setting up a.. 

path through the commutators for enciphering the first letter, say letter A. 

When key A is depressed,_ universal bar 44 is caused to move downward, moving 

c.ontact lever 17array from contact 21 and·allowing current to pass from battery 

16 along conductor 23, through closed contact 22, contact lever 18, conductor 

24, outer-ring contact 29 of end plate 301, into the commutators through which 

it follows the continuous line and returns via. outer-ring co.trtact JO of end 

plate 301, conductor 25, contact lever 19, closed contact 47 to indicating 

device 14, conducto~ 4.3 and back to battery 16. After the letter ~' corresponding to indicating device 14, has been recorded, key A is released and 

br eak:s contact at 22, at the same time allowing universal bar 44 to return to 

its normal position. When universal bar 44 returns to its normal position 

·contact 21 is closed reestablishing a circuit through the inner-ring contacts 

- 10 -
0 REF ID:AQ:7509 0 

of the commutators. But·commutator 104 having been displaced an entire~ 

new pa.th through the commutators is now available for enciphering the letter A, 

if ·it is again to be enciphered. 

The cjeciphement or the letter·Q takes place in an analogous manner. 

Tμe machine having been reset to the key, 

· _/'ehe closing of main switch 36 as before causes a current to ·flow through one 

'of the inner-ring contacts to selector magnet 10, moving .commutator 103 one 

. . 

step forward~ Depression of key Q establishes a circuit as follows: Battery 

16, closed switch 36, conductor 23, closed contact 42, contact lever 19, 

conductor 25, outer.;.ring contact JO, thence along the continuous line into, 

through and back through the commutators, emerging at outer-ring contact 29, 

conductor 24, contact lever 18, closed contact 46, indicating device 15, corresponding to the letter A, conductor 43, be.ck to battecy 16. When key Q 

is released, universal bar 44 returns to its normal position and again a 

circuit is established through the inner-ring contacts of the commutator. 

But since commutator 103 has been.displaced, a new path is now av:aila.ble for 

deciphering the letter Q it the Q key is again depressed. 

The period of the sequence of ·alphabet selection produced bythis arrange~ 

ment is variable and will depend upon four variable !actors, namely (1) the 

wiring of the inner rings of contacts of the double-ring commutators; (2) the 

horizontal permutation of these commutators on the shaft; (3) the alig~ent of 

the commutators and (4) the manner in which the inner ring of contacts on end 

plate JOl are connected to the selector magnets. , 

In Fig. 5 the invention as regards. double-ring commutators to perform 

substitution and control functions is embodied in a cryptograph of the first 

category as briefly described in general terms in the first part of this 

specification. It will be recalled that in cryptographs of this category, 

there are two end plates or identical construction and a reversing switch 

which, when set in the enciphering position, connects the switches of the. keyboa.rd to the contacts of one of the end plates, say the right-end plate, and 

the indicating devices are connected to the contacts of the other end plate, 

~y the left-end plate; whilE'. when set in the deoiphering position, the 

reversing switch reverses the order of connections between the .sWitches of 

i 

I 

l . I 

the keyboard, contacts of the end plates, and the indicating devices, so that J' 

_____ t_h_e_k_ey_bo_ard_ ew_i_t_ch_e_s_ar_· _e_n_ow __ c_o_nn_e __ ct-~-d-~-o-th_e_l_e_r_t_-e_n_d_p_la_t_e_a_n_d_th_e_in_di_catiug 
( 

\__J 

REF ID:A67509 

devices are connected to the right end plate. 

Accordingly in Fig. 5 there is shown a keyboard 52, a bank of indicating 

devices 53, a left end plate 301, a right end plate 302, and a reversing 

switch 54, together with other parts homologous to those shown in the precertain··:of the certain of the • 

ceding figures. Only~ keys of the keyboard and~ indicating devices of 

the bank of indicating devices are shown in circuit relationship, it being 

understood that the remaining·keys and indicating devices are connected in 

homologous manner. 

Assuming that the cryptograpb is to be operated for enciphering,' the 

switch 54 is set to enciphering position, which arranges for circuit continuity 

along the continuous lines 55 to 58. The main switch 36 is now closed and 

a circuit is established as follows: Battery 16, closed switch 36, conductor 

23, universal bar switch lever 17, closed contact 21, conductor 26, inner-ring 

contact 127 of right end plate 302, through the commutator unit, to inner-ring 

contact 128 of left end plate 301, conductor 38, selector magnet 10, conductor 

4.3back to battery 16. Commutator 104 is angularly displaced one step. Key A 

is now depressed. The circuit through the inner-ring of contacts of the commutators is now broken, as univeraal bar 44 breaks the contact at 21. At the 

same time a circuit is established through the outer-ring of contacts of the 

commutators, as follows: Battery 16, closed switch 36, co~ductor 2.3, contact 

lever 18 operated by key A, closed contact 22, conductor 24, through the reversing switch 54 along conductor 55, conductor 224, outer-ring contact 29 of 

right end plate 302, into and thrOUg~ commutators 105, 104, 103, 102, 101, via 

their outer-ring contacts, an outer-ring oontact 229 of left end plate .301, 

conductor 243 to the reversing switch 54 through the latter along conductor 5S, 

thence along conductor 343, indicating device 14, corresponding to the letter 

Q, conductor 4.3 to battery 16. When key A is released, universal bar 44 returns 

to its normal position, reestablishing contact at 21. Again a curreDt flows 

through the inner ring contacts of the commutators, ~tering ~t· contact 29 but 

now emerging at some contact other than 128 on left end plate .301, since 

commutator 104 has been displaced. A selector magnet is energized, and a new 

path is set up for the passage of the next enciphering current if A is again 

depressed. 

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()· REF ID:A67509:-)\ 

"'--- \....,, 

If key Q is de~ressed, instead of key A, the circuit is as follows: 

Battery 16, closed switch 36, conductor 23, switch lever 19, closed contact 

. . . 42; conductor 25, through reversing switch along path 57, conductor 325 to 

an outer-ring contact .30 of right end plate 302, thence through commutators 

to.an outer-ring contact 230 of left end plate .301, conductor 425, through . . . . 

·the reversing switch along path 59, conductor. L.4.3 to some one of the indicating 

·devices of 53• say the one corresponding to letter z. In other words, the 

relationship between. A and Q is not reciprocal, when the cryptograph is set 

at the enciphering position, as is the case in the preceding figures. Here 

A in plain text gives Qin cipher, but ~-in plain text gives Zin cipher. 

In order to effect decipherment, the reversing switch 54 must be set for 

the deciphering function. This causes the paths through the reversing Slfi teh 

54 to follow along the dotted lin~s instead or along.the·continu6us lines. The 

operation immediately subsequent to closing main switch .36 is now.exactly the 

same as ·before, when the encipherment of letter A was described. · This is 

because.the circuits to the selector magnets are associated with the innerring contacts of the commutators, and these contacts are not connected to aIIY' 

of the contacts in the reversing switch 54. ·In, the first enciphering operation~ 

the letter A was enciphered.by Q. The decipherment of Q will now be followed. 

Depressing the Q key causes universal bar L.4 to break the circuit at 21, as 

before, but the.substitution circuit is now part~ different from what it was 

when key A was depressed in enciphermen"f:;. The circuit is now as follows: 

Battery 16, closed switch .36, conductor 23, contact lever 19, closed contact 

42, conductor 25, through reversing switch 54 along dotted path 257, conductor 

2431 outer ring contact 229 of left end plate JOl, through the outer-ring . \ 

contacts of the commutators to an outer ring contact 29 of right end plate 3021 

conductor 224, through reversing switch 54 along dotted path 255, conductor 

225, indicating device A, conductor 43, to battery 16. Thus Q i~ cipher yields 

A in plain language. If key A is depressed instead of Q, the control circuit is exact13 the same as ~hen Q was depressed but the substitution circuit is as follows: Battecy 16, closed switch J6, conductor 23, ·contact 

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1------- ~-

REF ID: A67 50 9 ,~-'\ 

'---,! 

lever lS, closed contact 22, conductor 24, through reversing switch 54 

along dotted path 255, conductor 525 to an outer-ring contact of left end 

plate .301. The current will emerge at someouter-ring contact of right 

end plate 302, thence go to and through the reversing switch 54, and from 

there it would go to some one of the indicating devices of 5.3, the exact 

one not being indicated in the figure. In an;y case it will be the plaintext letter which was enciphered when the cryptograph was in the homologous 

position in the enciphering cycle. 

A fifth embodiment of the invention utilizes single-ring commutators to 

ser:ve both as substitution commutators and control commutators by means of a 

gang switch of 26 contacts inserted in the circuits through the commutators. 

Figure 6 shows a schematic diagram of this form of the invention. 

Having now particular reference to Figure 6, with the exception of the 

gang·mtch and relays which will be described present~, the elements shown 

therein are similar in construction and function with the corresponding elements 

shown in the preceding figures. Gang switch 85 is mere~ a device for breaking 

one complete set of 26 contacts simultaneously and at the same time making 

another set of 26 contacts simultaneous~. It is operated by magnet 83 and 

· associated relays. The action of this form of the invention is as follows: At · i 

the beginning of operation, switch 36 is closed, setting up circuits through relays 113 and 114, as followss battery 16, conductors 23, lll, switch lever 17, 

closed contact 72, conductor 112 relays 113 and 114, conductor 124, to battery 16~ 

Relays 11.3 and 114 are energized, causing armatures SO and 108 to establish contact at 81 and 109, respectively. By means of a mechanical locking arrangement, 

once a.ruiature 80 has been attracted by relay 113 the contact established at 81. 

is locked until releas.ed by the action of relay 68; simil~ly when armature 

108 of relay 114 has been locked into contact position at 109, it stays 

locked until relay 110 is energized. Consequently, although contact 72 must 

be clos.ed in order to establish contact at 81 and 109., after ,the latter 

contacts have been established they will remain so even if ·c~ntact 72 is 

broken by depressing universal bar 44. When key A is depressed universal 

- 14 -

' I 

I 

~. -.--....... ..-~------ ----~~-- "'"·----·---·-.-- ___ .--.~-~--- ~- ----- - -----~ - --- ~ -- - ----- _______...._ ___ ~- - ----~~~----~·-- -~ . J 
. ' . 

bar 44 causes contact lever 17 to make contact with contact 21, setting 

up the following circuit: from source of power 16 through conductors 23, 

111 and contact lever 17, to closed contact 21 through. conductor 79 and locked 

lever 80 of relay· 113 to contact 81, thence through conductor 82 through gangswi tch magnet 83 and conductors 116, 124 back to.source of power 16. Vlhen 

gang-switch magnet 8J is energized, armature 86 is attrc..cted, causing gangswitch 85 to. 'disengage a lower set of twenty-fix contacts and to engage an 

upper set of twenty-six contacts. Switch levers.88, 188, 288, 388, 488 and 588 

are five of the ·set of 26. switch levers controlled by gang switch 85; contacts 

90, 190, 290, 390, 490 and 590 are five of the set of 26 lower contacts controlled by the switch levers of the gang switch 85; contacts 91, 191, 291, 391, 

491 and 591 are five of the se~ of ·26 upper contacts controlled by the switch 

levers of the gang switch 85. Referring to contacts 91 and 191, which have 

been closed by energizing gang-switch magnet"83 as noted· above, there is set 

up a- circuit as follows: from sotirce of power· 16·through conductor 23 to 

closed contact 46, (the key A still being depressed) through contact lever 18 

and conductor 119 to closed con.tact_· 91, through contact lever S8, and conductor 

76" to a contact 29 on end plate .301, commutators and separators 1, .305, 2, 306, 

' 3, ·307, 4, .308, and 5. Commutator 5 is a.reversing com.'Iluta.tor, and therefore 

the current goes back through the commutators and separ.s.tors 5, 308, 4, 307, 

3., 306, 2, 305, l; and returns to end plate 301, emerging at contact 30 on end 

plate 301; thence along conductor 84 and contact lever 188 to closed contact 

191, through conductor 93-, contact leve:r; 19, closed contact 42 along conductor 

121~ to indicating device 14, thence along conductor 43 to relay magnet 68 ~nd 

back along conductor 77 to battery 16. 

When indicating device 14 is energized, a type bar is cause6,b-J means not 

is 

shown, to print the letter Q., EOOOd~ which ~ t::ie cipher 

equivalent of the plain-text letter A. ·when relay magnet 68 is energized, 

contact lever 80 disengages contact 81 and engages contact 100, deenergizing 

switch control magnet 83 and allowing gang switch 85 to disengage the upper 

set of 26 contacts, among which are contacts 91 and 191, and engage the lower ,. 

set of 26 contacts, among which are 90 and 190. This sets up a circuit as 

- 15 - I 

6....-~~--'~~-'-'---=-~---'-'~_c_='-"-'-~-'--~~~-='-"-'·'==~:~=-~--'---'--"--'-.;_;__c.~~~~~~~-_J 
- --- ---·-----

REF ID:A67509 n '--.....,::· 

follows: batter;J 16, conductors 23 und 111, universal-bar contact lever 17, 

closed conts.c.t 21, conductor 79, cont&ct. lcvsr 30, contact 100, conductor 122, 

selE:lc·cor mc.g·11et lJ, conductor 106, closed contact 190, contact lever· 188, 

conductor 84, contact 30 ~n end plate 301, to, through and back through 

commutators 1 to 5, contact 29, conductor 76, contc.ct lever 83, closed 

contact 90, conductor 107, contact lever 108, closed contact 109, relay magnet 

110, conductors 123 and. 124, back to br.tter-.r 16. 

~!hen selector magnet 13 is energized, com:ilut.:itor 1 is angularly displaced 

through l/26th of a revolution, c.nJ. a neir. set of ci:ctkits is formed in the 

commutator unit. Relay magnet 110 having been energized, contact lever 108 

is· caused to disengage contact 109. This breaks the circuit through the 

selector magnets and prevents energizing selector magnet 13 a second time. 

No further action of any !)art can take :1lace until the t'!lo relays 113 and 114 

are &gain actu&ted. This h'l~Jrens '.i:}:cr.. ke:y A is r8le~secl, vihich €Stablishes 

o. circuit e.s follows: batte:-y 16, conc>1ct:>rs 23 and 111, cont.s.ct lever 17, 

closed contr.ct 72, conductor 112, magnets 113 and 114, ba.ck to battery 16. 

As e:::::'lPir:ed abovE' .P arruc..tures 80 and 103 arc locl{ed in ·Contact-making 

::-io:iticns d 81 a:i:d 109 until c:.nothe!' key of th£ keyboard is depressed, 

causing the device to operate in the saine Iilr..nner c.s l:ersinbefore described. 

- · 16 - J 
( f, REF ID: A67509 ( 

A means of providing an irregular wheel movement 

in Cipher Machinesusing cipher wheels. 

The basic principle of this invention utilizes the cipher wheels of 

the cipher machine to provide an irregular selection of the particular 

wheel which is to be moved. A method of effecting this selection is to 

provide, in addition to the present ring of 26 contacts on each face of the 

wheel, a second ring of 26 co~tacts, which contacts are independent of the 

first mentioned set of contacts, but are connected to each other in an 

irregular manner, analogous to the manner in which the first mentioned set 

of contacts are connected. Also the end plates will bear a double ring of 

contacts·which coincide exactly with the two rings of contacts on the face 

of each cipher wheel. These two rings of contacts on each end plate are 

connected as indicated in Figs. 1 and 2 of the attached drawing. 

The action of the machine is as follows: When a key is depressed, two 

contacts are closed, namely, (1) the key contact which allows a clU'rent to 

pass thr9ugh one of the above-mentioned rings of contacts to operate an 

indicating device giving the encipherment of the letter corresponding to 

said key and (2) a universal contact which permits current to enter at a 

single contact of the other of the af'orementioned rings of contacts on one 

of the end plates, pass through one of the contacts of the corresponding 

rings of contacts of a1l the cipher wheels, and pass out at one of the 

contacts on the corresponding ring of contacts of the other end plate, and 

thence to a selecting magnet which permits the cipher wheel corresponding 
\ /r .. 

\ /'~ \ , 

REF ID:A67509 -...._ ', __ _../ 

thereto to move forward. 

Figure 1 is a schematic diagram of the invention. 1, 2, 3, 4, and 5 

are the hereinbefore described cipher wheels; 19 and 20 are the end plates, 

6, 7, 8, 9, 10 are the wheel selector magnets which allow a mechanism to 

step one of the wheels forward at each depression of a key; 11 and 13 are 

the rings of contacts through which the current passes to the wheel 

selector magnets; 12 and 14 are the rings of contacts through which the 

"key to lamp" current passes; 15 is the key contact; 16 is the above-mentioned 

universal bar contact; 17 is the source of power; 18 the reversing switch; 

21 is the indicating device; and 22 is the connection to the universal contact 

which may be connected t'o any contact of the rings of contacts 11 on end 

plate 19. 

Fig. 2 shows one1manner in which the ring of contacts on end plate 20, 

through which the current passes to the selector magnets, are connected to 

the wheel selector magnets. 

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