REF ID:A67560 • 

8 

April 14, 1936 

I ea &t.tach!.q herei.to a ffYiaed draft. oi speciticationa and *-•iD&• caqr:tng thu harld.oi>U"atld Cl."JPtoanrihio 

device whicb ••• ariginal.17 fonrfU"dod to JOU about Juq 6, 

19.35, tor the prepan.tiou of pa.tent apeoU'iC1.LUons. 

.l\tached: 

Dzoatt of •pecS.fioa t.iona 

l>rsw1Dg1 

1'1111aa F. Friedaan • 

lA\pproved for Release by NSA on 09-09-2013 pursuant to E. 0. 1352§ 

Cow tor Mr. Friedman 
REF ID:A67560e 

This invention relatesto cryptographic devices and has tor its object 

the provision ot a hand-operated device capable of attordi:ng a relativeq 

high degree of security without involving the use of complicated mechanism.a. 

Another object is to provide a device useful in cryptographic and cry:ptanalytic investigations requiring the use of sliding alphabets. 

tour 

The invention is explained in connection with &1DI figures. Figure 1 

Figure 2 shows a single section of another form of the device; Fi~e 3 shows a base; 

is a front and side elevation of one embodiment of the devicej/Figure 4 

top view 

is a.,, '• " 'e •wi• '' ot a second embodiment of the device. 

Ref erring to Figure 1, in this embodiment the device consists of a 

base, 1, on which are horizontally fastened a series of cylindrical rods, 

21 forming a set of channel W81'S1 31 into which paper strips, 4, may be 

inserted and slid from left to right or vice versa. In the specific embodiment disclosed herein the device comprises 25 such channel wqs, m+t;wuttc 

~S"l¥AJ but the device is by no means limited to this number. 

The number chosen in this embodiment is merely a convenient number, and it 

may be increased or decreased within certain limits in other embodiments 

without material.17 departi!Jg from the be.sic nature of the device. A rule, 

or reading guide, 5, attached to a reading guide slide, 6, can be slid 
REF ID:A67560 

to the left or right on a reading guide slide rail, 7. End bars, 8 and 9, 

serve as stops against which the reading guide 5 can be brought at the 

end of' its travel to the left or right. To the back of the be.se 1 is 

fastened a hinged supporting frame, 101 which can be pulled out to support 

the device in a slanting position as it rests upon a table, desk, or other 

plane surface. Or, if the operator prefers to lay the device f'lat upon 

the table, the rubber feet, ll, at the four corners of the bottom or ba.se.l 

will support the device and keep it from sliding about on the table. 

As stated above, into the channel ways 3 there are inserted strips 

of paper 4 hereinafter called alphabet strips, upon which appear sequences 

of' letters of' the alphabet, ea.ch sequence being repeated on the strip, and 

the letters being equidistant from one another throughout. The purpose 

of' the duplication of sequence will appear presently. The letters on the 

alphabet strips ID8.7 be in normal order or in disarranged order; if' the 

latter, the various alphabets my or may not be different. Assuming, 

however, different alphabets are being used, each strip bears an identifying 

mark such as a number, 12, so that the alphabet strips Jll81' be inserted into 

the channel ways C according to some pres.greed key. For example, in Figure 1 

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is shown a set of' 25 channel W&J'S into which 25 different alphabet 

strips 4 have been inserted accordi:ug to the following key-, reading 

from the top downwards 

14-16-9-6-22-25-23-5-12-24-13-21-18-1-7-17-20-19-15-8-11-2-3-10-4 

Ii' another embodiment of the device should include more than 25 channel 

ways, additional alphabet strips 11181' be inserted, according to a longer 

key. 

HaviZJg inserted the alphabet strips into the channel ways in kBJ" 

order, the device is now ready for use either to encipher a plain language 

message or to decipher a cryptogram which has been enciphered by means oi' 

the device, alphabets, and key- shown in Figure 1. Suppose this plain-text 

message is to be enciphered: 

ACCORDING TO .AN OFFICIAL REPORr FROM MILITARY AUTHORITIES • • • 

Moving the reading guide 5 to the lert, and bringing it against the 

' left end bar 81 the operator proceeds to align, in a column immediatel.T 

to the right of the reading guide, the first 2S letters of the message. 

This is most conveniently done bJ placing the eraser end of a pencil upon 

the successive desirailetters as found on the successive alphabet strips 4 

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f'rom the top downwards, and pulling or pushing the alphabet strips in 

their channel wqs toward the reading guide so that each strip stops 

with the proper letter just to the right of the right-hand edge or the 

reading guide 5. When the alphabet strips are being aligned on the left-hand 

side of the device, as in the above procedure, the operator confines his 

search for letters to the left-hand half' of the duplicated sequence on each 

alphabet strip. 

When all 25 alphabet strips have been aligned as indicated, there is dieclosed a multiplicity of columns of' letters to the right of the plain-text 

column of letters thus aligned. All these columns of letters, except one, 

are columns of cipher letters, each column representing a cipher equivalent 

of the plain-text column. The single exception is the column which is the 

25th removed from the plain-text column set up by the operator, and is merely' 

a repetition of that plain-text col'Ullll. One or these cipher columns is 

selected at random and is recorded 1n 5-letter groups. The reading guide 5 

is useful in this operation, since by placing it alongside the column selected, 

reading or the cipher column is facilitated. &tpt>o•e that the reading guide 5 

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is moved so that its left-hand edge aligns a column of cipher text. These 

letters are recorded and constitute the cipher letters for the first 25 

plain-text letters. 

The reading guide S is now moved to the extreme right of the device, 

up against the right end bar 9J the next 25 letters of the plain text are 

aligned against the left edge of the reading guide 5. Again a set of 

columns of cipher letters are disclosed to the left of the reading guide. 

O~e of these columns is selected at random and again a set of 25 cipher 

letters representing the second set of 25 plain-text letters is recorded. 

If the message contains more than SO letters, the foregoing procedure is 

repeated until the entire message has been enciphered. There is no need 

to indicate to the recipient of the message wlu.ch column is selected for 

the cipher equivalent of each set of 25 plain-text letters, as will be 

noted presen~. 

To decipher the message, having the alphabets and the key according 

to which they have been arranged, the operator merely proceeds as in 

encipherment, aligning the alphabet strips in their channel ways so that 

2S 

the firsj?/cipher letters of the 017ptogram are in one column. Be then 

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REF ID:A67560 

examines all the other 25 columns or letters, looking for one which conta.ins intelligible text throughout its extent from top to bottom. There 

will be one and onl.7 one such column, and this will be the plain-text 

equivalent of the column of cipher text set up on the deVJ.ce. The reading 

guide 5 is useful in this search for the plain-text column, as it can 

readily be moved to scan the successive columns f"rom left to right, or 

from right to left. The plain-text column thus found is recorded in 

I 

word lengths and the operator proceeds to set up the next 25 cipher 

letters on the right-hand side of the device. Again he looks for a 

plain-text column and records it when f'ound. He continues this process 

until the message has been completel.1' deciphered. 

Although in the figures accompa!J1'1ng this description a device is 

shown in which cylindrical rods are riveted to a base at regular intervale from one another to .form the channel wqs into which the alphabet 

stripe are inserted, it should be understood that 8.11if other means ms.7 

be employed to form the channel ways. For example, a series of elongated 

metal strips known in the trade as 11 card holders0 , used ordinaril.T to 

hold narrow strips or paper bearing names of mall-box owners in apartment 

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houses, eto., 11181' be used to form the channel ways5 these card holders may 

be riveted to the base, or spot welded to it, or attached in &JV' other 

suitable manner. Or, the channel ways mB.7 be formed by milling grooves in 

the base 1 itself, which :may be made of molded bakelite, for example. In 

such case the grooves are made by a rotating cutter which undercuts at the 

two edges, forming a channel way such as is commonly found in slide-rules. 

Figure 2 shows such a section in the form of a piece of ba.kelite or similar 

material, 13, in which five such channel ways 3 have been cut. Sections 

with equal or unequal mmbers of channel ways may be easily provided and 

given identifying symbols such as letters, A, B, c, •••• 

In Figure 3 there is shown a base suitable for use with such sections of 

channel ways. Thus, instead of having all the channel ways on a single base, 

as is the case in Figure 1, the base is merefy made in the form of a fiat 

surface onto which sections of channel ways 11181' be positioned and temporari~ 

fixed, so that rearrangements of' sections can be made according to subsidiary 

keys. Referring to Figure 3, the base 1 is a plane surface across which has 

been cut a slot, 14, for carcying a sliding clamp, 15, provided with a 

knurled thumb screw, 16, for fastening the clamp into position. End bars 8 

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and 9 elevated above the ba.se by supports, 17, and back stop, 18, serve 

the same purpose as 8':-mil arq designated end bars ot .Figure 1. 

Using a base such as that shown in Figure 3, with several sections 

such as that shown in Figure 2, iDne method of' operation or this embodiment 

ot the invention is shown in Figure 4. In that figure there are five 

sections of' 3, 4, 5, 7 and 8 channel W'81'S, giving a total of' 27. First, 

the sections are temporariq fastened to the base in the alphabetical 

order of their identifying symbols. Then the 27 alphabet strips would be 

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inserted in the f!I consecutive channel W81'S according to the predetermined 

numerical key alrea<V ref'erred to above in connection with Figure 1. = i 

~1 a Phf'g 7 'k I 1:" 7 ..... ,. ... 7 

<b•w --

, •• • ' adb ••a>• 1 •• p v••tl!• ••>p•·Jr+-• • h' •11 •nwlw_c.en;t¥AIJ"XIJJ <fJ d;&p1M • "4J 

Z""'* •1¥ To encipher a given message, there would then be a subsidiary 

or specific key, also arranged for in advance b,y means of an indicator in 

the message, which would direct that the sections be now placed onto the 

base in a mixed order, S81' E - D - A - B - C, as shown in Figure 4. The 

encipherment of a message would then proceed exactly' as before. In another 

message, the indicator for the sectional arrangement might be different, 

say one calling for the sequence of sections D - A - C - E - B. Thus, with 

five sections there could be 120 different arrangements of sections on the 

base, even though only one set or !S alphabet strips is employed. The purpose of this is, or course, to increase the keying possibilities of the 

device, and to impart uniqueness to successive messages, without going to 

the trouble of making a complete rearrangement of all • alphabet strips 

in the set or 'jJ" channel wqs. 

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REF ID:A67560 

fw1lt 8"' +<SM t Joww +•e••uaa• •'' f-CGlllb"wql' e..,drl1P••-=-

The Dl8JV' uses of this device, with variable alphabets, in ccyptographic 

or cryptamqtic studies will be apparent to all skilled in the art and 

nothing further need be said on this score except that there has existed 

tor man;r years a hitherto unfulfilled need tor a simple device of this 

type, suitable for the insertion of sliding alphabets. 

1. A cryptographic device consisting of a base upon which is provided a plurality of channel WBTS in which strips of character-bearing 

material 11181' be inserted and slid into alignment. 

2. A cryptographic device consisting of a base upon which is proVJ.ded a plurality of channel ways in which strips of character-bearing 

material may be inserted and slid into alignment, the channel ways being 

open at both ends. 

3. A cryptographic device consisting of a base upon which is provided a pluralit7 of channel ways in which strips of character-bearing 

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material mtq' be inserted and .slid into alignment, and a slidable guide 

rule tor making excursions transversely across the channel ways. 

4. A cryptographic device consisting of a base with a hinged 

support rest attached to the reverse surface of the base; a plurality 

of members fixed to the obverse surface of the base at equidistant intervals to form a plurality of channel wqs for the insertion of characterbearing strips bearing alphabetic sequences; solid members fixed at opposite 

• 

ends of' the channel ways and resting upon the members forming the channel 

ways; and a guide rule attached to a sleeve permitting the guide rule to 

be slid transverseJ.T across the channel 11'81'S• 

5. A Cl'J'ptographic device consisting of a base; a plurality of' grooved 

members providi?Jg channel 1f81'S for the insertion of slidable, characterbearing strips, eaid grooved members bearing distinguishing symbols to diff'erentiate one from another and containing one or more said channel WB.J'SJ 

means for temporariq fixing said members to the base in linear juxtaposition 

to afford series of juxtaposed channel wqs; end members attached to said 

base transversel.J' to the direction in which the channel wqs extend and 

raise above the ends of the channel wqs so as to provide stops against 

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which an instrument is brought at the end of its travel in setting up 

letters tor enciphering and deciphering; and a slidable guide rule 

movable transversel1' across the channel ways. 

6. A cr;yptographic device of the character specified in Claim 5, 

• in which said grooved members contain equal numbers or channel ways. 

7. A cr,yptographic device or the character specified in Claim 5, 

in which said grooved members contain unequal numbers of channel ways. 

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