REF ID:A70433 

Patented Mar 5, 1946 2,395,863 

UNITED STATES PATENT OFFICE 

2 395 863 

CRYPTOGRAPHIC DEVICE 

\'Vtlliam r rnedman, \'Vashmgton, D C 

Apphcahon October 19 1939 Serial No 300 212 

19 Claims (Cl 35-2) 

(Granted under the act of March 3 1883 as amended Apul 30 1928 370 0 G 757) 

The mvent10n described herem may be manufactured and used by or for the Government for 

governmental purposes without the payment to 

me of any royalty Lhereon 

This mvent10n relates to cryptographic devices 

and has fol its obJect the piovis10n of a handoperated device capable of affording a relatively 

high degree of security without involving the use of complicated mechamsms 

Another obJect is to provide a device useful in 

cryptographic and cryptanalytic investigations 

requiring the use of slidmg alphabets 

The mvent1on is desc11bed with iefererice to 

tbe accompanying drawings m which 

Fig 1 is a perspective showmg one fo1m or em- bodiment of the mvent10n 

Fl.g 2 is a top plan v1i;:w of another embodiment 

of the mvent10n 

Fig 3 is a cross-sect10n taken on the line 3-3 

of Fig 2 

Fl.g 3a is a fragment of the same section on an enlarged scale showmg the T-grip for the guide 

rule m operative position 

Fig 4 is a top view of the form of mvent10n of 

F1g 1 showmg the guide rule m shifted position 

Fig 5 is a top plan view showmg another em- bodiment of the mvent10n m which the base is 

composed of separate detachable grooved sect10ns 

Fig 6 is a perspective showmg one of the 

grooved sect10ns and 

Fig 7 is a perspective showmg a frame sti ucture 

and sub-base on which said grooved sections may 

be assembled 

Referring to Fig 1 m this embodiment the device comprises a base I on whwh are horizontally 

fastened a series of cyhndrical iods 2 formmg a set of channel ways 3 mto which character bearing strips 4 may be inserted and shd from left 

to nght 01 vice versa In the specific embodiment 

disclosed herem the device comprises twenty-five 

such channel ways but the device is by nq means limited to this number The number chosen m this embodiment is merely a convement numbe1 

it rests upon a table desk or other plane surface 

Or if the operator prefers to lay the device flat 

upon the table the rnbber feet 11 at the four 

corners of the bottom of base I will support the 

5 device and keep it from sl1dmg about on the 

table 

As stated above mto the channel ways 3 there are inserted character strips 4 of paper or other 

suitable mate1 ral, hereinafter called alphabet 

10 st11ps upon which appear sequences of lette s of 

the alphabet each sequence bemg repeated on the st11p and the letters bemg eqmdisLant from 

one another thioughout The purpose of the 

duphcat10n of sequence will appear presently 

15 The letters on the alphabet strips may be m nor- mal order or m disarranged orde1 if the latte1 

the va11ous alphaoets may or may not be different Assummg howeve1 different alphabets are bemg used each striJ? bears an ident1fymg 

20 ma1k such as a number 14 so that the alphabet 

st11ps may be inserted mto the channel ways 3 

according to some preagreed key For example 

m Fig 1 is shown a set of twenty-five channel 

ways mto which twenty-five different alphabet 

25 strips 4 have been inserted according to the following key readmg from the top downward 

l4-l6-9-6-22-25-23-5-l2-24-l3-2ll8-l-1-ll-20-l9-l5-8-1 l-2-3-l0-4 

~o If another embodiment of the device should include more than twenty-five channel ways additional alphabet strip<> may be mserted according 

to a longer key 

Havmg inserted the alphabet strips mto the 

35 channel ways m key order the device is now ready 

for use either to encipher a plam language message or to dec1phe1 a cryptogiam which has been 

enciphered by means of the device alphabets and 

key shown m Fig 1 Suppose this plam-text mes- 40 sage is to be enciphered 

ACCORDING TO AN OFFICIAL REPORT 

FROM l.\ITLITARY AUI'HORITIES 

and it may be mcreased or dec1eased w1thm cer- 45 

tam limits m other embodiments without ma- terially depa1 tmg from the spirit of the mvent10n 

Movmg the readmg guide 5 to the left and 

brmg1ng it agamst the left end bar 8 the operator 

p1 oceeds to align m a column immediately to 

the llght of the readmg guide the first twentyfive letters of the message This is most conveniently done by placmg the eraser end of a pencil 

upon the successive desned letters as found on the successive alphabet strips 4 from the top 

downwa1 ds and pullmg or puslung the alphabet 

strips m their channel ways to\v ard the readmg 

guide so that each strip stops with the proper 

letter Just to the right of the right-hand ecf$e of 

A rule or 1 eadmg guide 5 attached to a reading 

guide shde 6 can be shd to the left 01 right on a readmg gmde slide rail 1 End bars 8 and 9 50 

serve as stops agamst which the readmg guide 

5 may be brought at the end of its travel to the 

left or right To the back of the base I is fastened a hmged support l 0 which can be pulled 

out to support the device m a slantmg position as 55 
REF ID:A70433 

2 2,395,863 

the reading guide 5 When the alphabet stnps are being aligned on the left-hand side of the 

device as in the above procedure the operator 

confines hls search for letters to the left-hand 

half of the duplicated sequence on ea{.,h alphabet 

strip When all twenty-five alphabet strips have been 

allgned as indicated there is disclosed a multiplicity of columns of letters to the llght of the 

plam-text column of letters thus ahgned All 

these columns of letters except one are col- umns of ciphe1 letters each column representing 

a ciphe1 eqUlvalent of the plam-text column 

The smgle except10n is the column which is the 

twenty-fifth iemoved f1om the plam-text column 

set up by the operator and is me1ely a repetit10n of that plam-text column One of these 

ciphe1 columns is selected at random and 1s 

iecorded in five-lette1 groups The readmg guide 

5 is useful m this operation smce by placing it 

alongside the column selected ieadi,_ng of the 

cipher column is facilitated Suppose that the 

ieadmg gmde 5 be moved so that its left-hand 

edge aligns a column of cipher text As sho'Vll 

m F'lg 4 such a column would iead as follows 

SNAFJ LXRJG GVWVA ATVWW PVNUT 

These letters ai e recorded and constitute the 

cipher lette1s for the twenty-five plam-text lettelS 

The ieadmg gwde 5 is now moved to the e:x- t1eme llght of the device up agamst the rignt 

end bar 9 the next twenty-five letters of the 

plam teJ..t are aligned against the left edge of the 

readmg guide 5 Agam a set of columns of 

cipher letters are d1scJosed to the left of the 

readmg gmde One of these columns 1s selected 

at 1andom and agam a set of t\\,enty-five cipher 

letteis rep1esentmg the second set of twenty-

.five plam-text letteis is recorded If the message contams more than fifty letters the foregomg p1ocedure is iepeated until the entire mes- sage has been enciphered The1 e is no need to 

md1cate to the iec1p1ent of the message which 

column 1s selected for the cipher equivalent of 

each set of twenty-five plam-text lette1s as will 

be noted p1 esently 

To decipher the message having the alphabets 

and the key accordmg to which they have been 

arranged the operator merely proceeds as n 

enciphe1ment alignmg the alphabet strips m 

their channel ways so that the filst twenty-five 

c1phe1 lette1s of the cryptogram a1e m one column He then exammes all the other twenty-

.five columns of lette1s lookmg for one wh1<'h 

contains intelligible text througl1out its extent 

from top to bottom There will be one and only one such column and this will be the plamtext eqmvalent of the column of cipher text 

set up on the device The i eadmg guide 5 is 

useful m this seaich for the plam-text column ~s 

it can readly be iUOVed to scan the successive col- umns from left to right or from right to left 

The plam-text column thus found is recorded 

in word lengths and the operator proceeds to c:et 

up the next twenty-five cipher letters on the 

right-hand side of the deVIce Agam he looks 

for a J;Jlam-text column and iec01ds it when 

found He contmues this p1ocess until the mes- sage has been completely deciphered 

In the form of mvent10n shown m Fig 2 the 

deVIce comprises a pair of hmged companents 

F-F of metal Bakelite or other suitable mate11al and foldable on one another m the manner 

of a book As here shown the grooved shdeways 3 are formed on the mner faces of the <;aid 

components by m11lmg or m the case where a condensation product such as Bakehte is used 

may be molded m the material In the embodl6 ment disclosed there are a total of thirty s.uch 

sllcteways fifteen m each component though it 

will be understood that the invention is not limited to any particular numbe1 It will be noted 

that the shdeways a1e open at their opposite ends 

10 so that the alphabet strips may be ieadlly inserted and f1eely extended outwardly the1efrom as they a1e shd mto ditreient pos1t10ns m the 

operat10ns of enciphermg and deciphermg As 

m other forms of the mvent10n a T-gllp 6 is <itlG tached to the guide iule 5 at its end for the purpose of mampulatmg the rule and is slldable m 

a channel 20 havmg therem undercut grooves 21 

and 22 fo1med laterally along its ms1de edges 

The gup 6 is provided with a spung-piessed ele20 ment 23 engaging m bottom gioove 21 and havmg an oppositely dlspased bead 24 engaging m 

the opposite g1oove 22 v.heieby the gllp 6 is 

mamtamed unde1 suitable shdmg tension m the 

channel 20 and wheieby the guide rule 5 is 

26 marupulated transversely m relat10n to the alpnabet stups 4 and the opposite end of the i ule 

is adapted to shde f1eely m a lateral .. undercut 

groove 25 fmmed m component F The gnp 6 

is llgidly seemed to the guide 1 ule 5 m the man30 ner of a T-square and may be so marupulated 

that the rule affo1ds a positive means of obtammg an accurate alignment m column formation 

of the chaiacters on said alphabet stups and m va1ymg ielat10ns f01 c1yptographlc purpases 

35 This foldable form of device presents a number of 

practical advantages among which may be ment10ned its compactness and po1 tab1lity also the 

foldable featm e permits exclusion of dust and 

dirt 

40 While m one form of device here disclosed c,ylmducal rods a1 e secured to a base at reguhr 

mtervals from one anothe1 to f01m the channel 

ways mto which the alphabet stnps are mserted 

it should be understood that any other means 4j may be employed to f01m the channel ways 

Fm example a series of elongated metal strips 

known m the ti ade as ca1 d holders ' used 

ordmauly to hold nairow stllpS of paper bearing 

names of mall-box ow11e1s m apartment houses 

,o etc may be used to form the channel ways 

these card holders may be riveted to the base, 

or spot welded to it or attached m any othe1 

suitable manne1 Or as disclosed m connection 

\VIth Fig 2 the channel ways may be formed 

55 by nnllmg grooves m the base I itself which 

may be made of molded Bakelite for example 

In such case the grooves a1e made by a rotatmg cutter whlch undercuts at the two edges, 

formmg a channel way such as is commonly 

60 found m slide-rules F.lgme 6 shows such a section in the f01m of a piece of Bakelite or sim1la1 

matellal 13 m which five such channel ways 3 

have been cut Sections with equal or unequal 

numbers of channel ways may be easily p1 ovided 

115 and given identifying symbols such as lette1s 

ABC 

In Fig 7 theie is shown a sub-base smtable for 

use with such sections of channel ways Thus 

mstead of ha vmg all the channel ways on a smgle 

70 base as is the case m Fig 1, the sub-base is 

me1ely made m the f01m of a fiat surface onto 

whlch sect10ns of channel ways may be posit10ned 

and temporarily fixed so that reairangements of 

sections can be made accordmg to subsidiary key3, 

75 Refe1rmg to F'lg 7 the sub-base la is a plane 
REF ID:A70433 

surface wlnch is provided with an unde1cut slot 

14 for carrymg a slldmg clamp 15 provided with 

a knmled thumb screw 16 for fastenmg the clamp 

mto pos1t10n End bars 8 and 9 elevated above 

the base by support<; 17 and back stop 18 serve 

the same purpose as s1m1Iarly designated end bars 

of Fig 1 

Usmg a sub~base such as that shown m Fig 7 

with several sections such as that shown m Fig 6 

one method of operat10n of thls embodiment of 

the mvent1on 1'> shown m F g 5 In that fl.gme 

theie aie five sections of 3 4 5 7 and 8 channel 

ways giving a total of twenty-seven channel ways 

First the sections are temporarily fastened to the 

base m the alphabetical oider of then 1dent1fymg 

symbols Then the twenty-seven alphabet strips 

would be mse1 ted m the twenty-seven consecutive 

channel ways accordmg to the p1edete1mmed 

nume11cal key already referred to above m con- nection with Fig 1 To encipher a given message there would then be a subsidiary or specific 

bearing thereon alphabetic character sequences 

and ind1v1dually movable m said ways, and means adJustable transve1sely of said strips to fac11Itate 

the readmg of said characters m varymg relat10ns 

'.S for enciphering and dec1phermg messages 

5 A cryptographic device comprismg a base 

having ve1t1cally giooved shde-\\aj's formed 

therem strips bearmg thereon alphabetw character sequence-s a'ld indnidually shdable m said 

l O ways and means adJustable transversely of said 

stJ.1ps fo1 fac1l1tatmg the iead1ng of said characters m varymg 1elat10ns for enc1phermg and 

dec1phermg messages 

6 A cryptographic device compnsmg a base 

15 provided with a plurahty of channel ways alphabet bearmg strips adapted to be md1vidually mserted and aligned m varymg relat10ns m said 

ways for cryptographic purposes a7J.d a slldable 

gmde rule for makmg excursions transversely 

20 along the channel v. ays and m relation to said 

strips for enc1phe11ng and dec1phe11ng messages 

7 A cryptographic device comprising a base 

hav ng 't supp01 tmg foot hmgedly attached to 

the und"r smface of said base a plurahty of 

l ... ey also a11anged form advance by means of an 

tndlcatoi 111 the message wluch would dnect that 

the sect10ns be now placed onto the base m a mn .. ed aider say E-D-A-B-C as sho¥.n in 

F1g 5 The enc1phe1ment of a message would 

then p1oceed e'l:actly as before In another mes- sage tl e mdicatm for the sect10nal a!fangement 

nnght be d1ffe1 ent say one calhng for the sequence of sect10ns D-A-C-E-B Taus with 

five sect10ns there could be 120 d1ffeient ariangements of sections on the base even though only 

one set of alphabet strips is employed The purpose of tlus is of course to 111crease the keymg 

poss1bi,1tles of the device and to impart umque- 35 

ness to successive messages without gomg to the 

'.!5 membei s fi'l:ed to the obverse surface of the base 

at eqmd1stant mtervals to form a plura!Ity of 

channel ways stups bearmg alphabetic se- quences of characters md1v1dually shdable m said 

ways a gl'1de mle adapted to be moved trans-

'lO ve1sely of said st11ps to facilitate the readmg of 

selected sequences of characters in varymg relations for ciyptographw purposes and stop mem- bers fo1 the gmde rnie disposed at oopos1te ends 

of said ch::innel ways 

8 A cryptographic de' ice comprismg a subbase mteichangeablc base-sections havmg 

grooves folmed therem to p1 ovide a plurality of 

channel ways means fo1 removably attachmg 

said sections m posit10n on said sub-base to pert ouble of mal~mg a complete rean angement of 

an alphabet st11ps in the set of twenty-five channel ways 

The many uses of this device with variable 

alphabets m ciytographic or cryptanalytic studies 

will be apparent to all skilled m the art and 

nothmg fur~her need be said on this score except 

that there has existed for many years a hithe1 to 

unfulfilled need for a simple device of tlns type 

suitable fo1 the 111se1 t10n of sl1d111g alphabets 

Changes mod1ficat10ns and eqruvalent arrangements are contemplated w1thm the scope of the 

mvent10n as defined by the appended claims 

I claim 

1 A cryptogiaph1c device comprismg a base 

p10v1ded with a plurality of horlZontal channel 

ways strips p10v1ded with discrete sequences of 

equally spaced alphabetic characters adapted for 

msert10n therem and adJustable mdependently of 

one another and means for fac111tatmg the readmg of said characte1s m selected columns 

2 A cryptog1 aph1c device compnsmg a base 

said base bemg provided with a plurahty of vertical channel ways and md1v1duallY adJustable 

stups bea1mg d1sc1ete sequences of equally spaced 

alphabetic characters adapted to be slidably mserted therem and means for facil1tatmg the 

readmg of said characters m selected columns 

and m different relations for c1yptog1aph1c purposes 

3 A ciyptcg1aph1c device comprismg a base 

formed with horizontally g1ooved sllde-ways 

therem mdiv1dually adJustable alphabetic strips 

shdable m said ways and means to fac11Itate the 

readmg of selected alphabetic columns 111 va1ymg 

1elat1ons fo1 c1yptograph1c purposes 

4 A cryptographic device compnsmg a base 

forMed with grooved shde-ways therem, st11ps 

40 mit different arrangements of said sections in 

Juxtaposed ielat10nshlp for cryptographw purposes cha1 actei bearing strips adapted for shdable mse1t1on m said channel W"YS and a shdable gmde i ule movable transversely across gaid 

45 channel ways and m varymg relations to said 

strips for enciphering and dec1phermg messages 

9 A combmat10n accordmg to claim 8 111 which 

said gi ooved sect10ns are of the same size and 

contam equal numbers of channel ways 

60 10 A combmation accordmg to claim 8 m 

which said grooved sect10ns are of d1ffe1 ent sizes 

and contam unequal numbers of channel ways 

11 A combmation accordmg to claim 8 111 

which stops a1e p1ov1ded at the opposite ends of 

li5 the channel ways to llnnt the movement of the 

sllde mle at the end of its travel 

12 A cryptographic device compnsmg a frame 

st1ucture and mcludmg a sub-base formed there- m a series of base-sect10ns ha vmg grooves 

60 therein to provide a plurality of channel ways 

means for iemovably attachmg said sections on said sub-base to peim1t different mxtaposed arrangements thereof for cryptographic purposes 

strips bearmg alphabetic sequence<: of characters 

65 sl1dable m said ways and a shdable gUide rule 

movable transversely of said strips and allgnable m varymg relat10ns with iespect to said characte1s for enc1phermg and dec1phermg messages 

13 A cryptographic device compr1smg a frame 

10 sti ucture and mcludmg a sub-base therem 

base-sect10ns grooved to p10v1de a plurallty of 

channel \\ ays, said sect10ns having different numbers of said channel ways and bemg differentiated from one another by d1stmguishmg sym. 

'10 bols, means fo1 detachably swurmg Bald .sectlon11 
REF ID:A70433 

4 2,39~,863 

on the sub-base Lo peimit chfferent juxtaposed 

arrangements thereof for cryptographic purposes strips beaung alphabetic sequences of 

characters movable m said channel ways a guide 

rule slidable t1 ansversely of said strips and align- 5 

able Ill varymg relat10ns with said characters for 

enc1phermg and dec1phermg messages and stop 

members at opposite ends of the channel ways to 

hmlt the movement of the slide rule at the end 

acters in varying relations for enciphermg and .. deciphermg messages 

17 A cryptographic device composed of hinged 

sect10ns foldable upon one another, said sect10ns 

bemg p1ov1ded on then inner faces with openended slide ways strips slidable m said ways and 

bearing thereon sequences of alphabetic characters and a gmde rule hinged to fold with said 

sect10ns said 1 ule being disposed transversely o.f 

of its travel 10 said stups and movable to facll1tate readmg of 

the characters m varymg relat10ns for enc1pheimg and dec1phermg messages 14 A ciyptograph1c device comprising a multiple base formed of separate sections said sections bemg mterchangeable with one another to 

permit different Juxtaposed arrangements for 

cryptographic purposes a plurality of channel 15 

ways in said sect10ns strips bearmg sequences of 

characters and individually slidable m said ways 

and a gmde rule movable transversely of said 

strips and ahgnable with said characters m varymg relations for enc1phermg and dec1pliermg 20 

messages 

15 A cryptographic device mcludn g a multiform base composed of separate sect10ns said sec- t10ns havmg g1ooved slide-ways therem and bemg mterchangeable with one another to permit 25 different Ju:i..taposed arrangements for cryptogiaph1c purposes stnps shdable m said ways 

and bea11ng the1 eon sequences of alphabetic 

cha1acters and gmde means disposed transveisely of said strips and movable to fac1htate 30 ahgnment of the characters m varymg relations 

for enc1phe1mg and dec1phe1mg messages 

16 A cryptographic device composed of hmged 

sect10ns foldable upon one another said sections 

havmg grooved sllde-ways formed on their mner 35 faces, strips shdable m said ways and bearmg 

thereon sequences of alphabetic characters, and 

gmde means disposed transversely of said strips 

and movable to fac1htate ahgnment of the char18 A cryptographic device compr1smg a pair 

of hmged components foldable upon one another, 

said components bemg provided on their Inner 

faces with open-ended sllde ways a gmda rule 

hmged to fold with said components means operative with one of said components to mamtam 

said rule m a posit10n transveisely of said strips 

and movable to facihtate readmg of the cha1-

acters m column format10n and m varymg relations for enciphe11ng and deciphermg messages 

and te1mmal stops to 1Im1t the movements of 

said rule at either end of its tiavel 

19 A cryptogiaph1c devwe compr1smg hmged 

components foldable upon one another said com- ponents bemg provided on their mner faces with a plurahty of shde \\ ays a gmde i ule hmged to 

fold with said components a grooved channel 

f01med along the edge of one of said components m par alLhsm with the slide ways means mcludmg a sprmg-tens10ned element shdable m said 

channel for operatmg the said rule while mam- tammg the same m a position transversely of 

said stnps sa1d rule bemg movable to fpcJ11tate 

readmg of the characters in varymg relations and m column fo1mat10n for enciphermg and dec1phermg messages 

WILLIAM F FRIEDMAN 

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March 5, 1946 

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