US2313012A - Enciphering apparatus - Google Patents

Description

March 3- G. GARINIER 2,313,012

ENCIPHERING APPARATUS Filed Dec. 27, 1938 3 Sheets-Sheet l Mrch2,1943. G. GARNIER 2,313,012

ENCIPHERING APPARATUS Filed Dec. 27, L938 s Sheets-Sheet 2 March G. ARNlER ,31

ENGI PHERING APPARATUS Filed Dec. 27, 1958 s Sheets-Sheet 3 Patented Mar. 2, 1943 -r ENCIPHERING APPARATUS Gustave Garnier, Paris, France; vested in the Alien Property Custodian Application December 27, 1938, Serial No. 247,957 In France January 6, 1938 1 Claim.

The present invention has for object a very simple apparatus allowing to very easily and rapidly translate plain-texts into cipher and, reversely, cryptograms into plain-texts, and this with a number of available combinations so considerable that it is practically impossible for a non-authorized person to decipher them.

This apparatus essentially comprises a disc which is movable about its centre underneath a fixed plate or dial perforated with radial apertures. The letters of the alphabet are inscribed on the edges of said apertures'in such an order that it is easy to rapidly find each of them.

On the other hand, the movable disc bears on its entire annular zone capable of appearing at the apertures of the fixed dial, cryptographic characters or signs adapted to be substituted for the letters inscribed on the edge of said apertures, the number of said characters or signs being a multiple of that of the letters of the alphabet, and their positions in said zone being suitably chosen, so that for each position of the disc the characters appearing in the apertures opposite the letters of the alphabet are all different from each other.

Said movable disc is preferably composed of two or more elements which each bear a certain number of the cryptographic characters and the relative positions of which can be changed at will, so that the order according to which all said characters pass in one and the same aperture is Variable in view of multiplying the num ber of available combinations.

The accompanying drawings diagrammatically illustrate and by way of example only, a form of construction of the subject-matter of the invention.

Fig. 1 is a vertical section passing through the centre of the apparatus.

Fig. 2 is a top plan view. I

Figs. 3 and 4 illustrate separately the two elements of the movable'disc.

Fig. 5 is a section of a modification, made according to line I-I of Fig. 6.

Fig. 6 is a top plan view of this apparatus.

Fig. 7 is a plan view of the movable disc composed of four superposed discs, the three upper discs being partly broken away.

Fig. 8 shows the numbered crown, or ring.

Only a small number of the cryptographic characters have been illustrated in these figures so as not to unnecessarily complicate the draw ings.

II I designates a dial supported'at a short distance above a base H2, for instance by means of supports H3 or of a circular fiangaetc. Between this plate and the base is placed the movable disc pivoting about a pin HA. In this example the disc is composed of two superposed elements: a lower disc H5 and an upper disc I I6, which are secured to each other by any attaching means Ill allowing to change at will their relative angular position.

The dial HI is perforated with a certain number of radial apertures I I8 on one edge of which. are inscribed the letters of the alphabet, that is to say for instance the twenty-six letters of the English alphabet in their natural order from left to right along the successive apertures; in. the drawings, five apertures have been illustrated each bearing five letters and a smaller aperture:

bearing the twenty-sixth letter (Z). The an gular widths of these apertures and those of the solid portions separating them are substantially equal to an amount which will be called angular: pitch.

Concentrically with the row of apertures, a slot H9 in the shape of an arc of circle is provided. in the dial Ill, and the figures 0 to 9 or 0 to 10 are inscribed on one edge of said slot at intervals or angular pitches which are equal to the width of the apertures H8.

On the movable discs H5 and H6 the cryptographic characters are inscribed on the entire annular zone which, by rotating, passes under the apertures H8; these characters are arranged according to radial rows the spacing apart of which corresponds to the angular pitch previously mentioned, and according to concentric circumferences corresponding to the radial spacing apart of the letters of the alphabet along the apertures. It results therefrom that for each position of the double disc H5, H6, twenty-six cryptographic characters appear opposite the twenty-six letters of the alphabet and express the respective translations for this position.

In the example illustrated, the angular pitch is equalto %2 of circumference, and the disc bears 5X52=260 characters, that is to say the value of ten alphabets.

Each character is repeated thereon ten times, that is to say five times on disc H5 and five times on disc H6. 7

Figs. 3 and 4 show that the upper disc H6 is cut out on its periphery so as to have twenty-six teeth and twenty-six notches, each of said teeth bearing five characters and each notch allowing five characters inscribed on th disc H5 to be seen.

Attaching means H! are provided so that each tooth of disc I [6 can be moved and held stationary between any two radial rows of characters of disc H; the setting of one disc relatively to the other is easy owing to the numbering of the rows of characters on said two discs.

One of the apertures H8 is extended up to above the ring of numbers of disc H5 and allows of marking out the position of the latter relatively to the dial l l I.

For causing the double disc H5, H6 to rotate, use can be made of a pencil or of any stylus the point of which is engaged in the slot H9 and in one of the fifty-two holes l2!) provided in the periphery of disc H5. 7

It it is desired to rotate the double disc 12 number of steps, smaller or equal to 10, in the direction of the arrow F, the point is engaged in the hole I located opposite the number n inscribed on the edge of the slot H9 and said point is brought up to the end of the slot marked 0.

Thus can be caused to appear in the apertures H8, every time the movable disc is thus rotated, according to code agreedupon, one of the fiftytwo combinations of twenty-six characters corresponding to the fifty-two possible positions of the disc.

As these combinations of twenty-six characters can be changed by displacing the disc I 66 on disc H5; the operator has, in reality, at his disposal 52 2B=1352 cryptographic alphabets for translating the plain alphabet, This number is quadrupled if each elementary disc bears characters on both its faces.

On the other hand, the movable disc can itself be replaced by other similar discs but the characters of which are inscribed in different. orders, so that the number of cryptographic alphabets at the disposal of the operator is practically illimited.

The graduated slot H9 is particularly adapted to increase in a considerable proportion the num.- ber of changes of combinations utilisable during the translation of one and the same text.

For instance, the various elements of disc H 5e! l6 can be designated according to the successive figures of a number agreed upon beforehand, which can be as long as desired (the decimals of the number 1r amongst others).

The successivedesignation of the elements. of the disc can also be based on a countersign agreed upon; for instance with the word Vendome, V. will be'designated by 22 steps of the rotating disc, E'by 5 steps and N by 14 steps etc.

These two methods of designation are indicated only among an infinite number of others the choicev of which can always be modified as thecorrespondents desire.

The direction of rotation of the disc can itself be conventionally changed, for instance that of. the arrow F on odd days, the reverse directionon even days, etc. 7

It is to be noted that the. distribution of; the characters on each disc, whether the latter is double as illustrated, or triple, or quadruple, etc. or simple, must always be established in sucha manner that all the combinations of twenty-six characters which the disc is capable of presenting under the apertures H8 are differentv from each other, and that each of them never comprises a repetition of one and the same character, which repetition might prevent the easy deciphering of a secret text.

In th example illustrated, the disc .is dividedinto fifty-two sectors or steps, but it is to. beunderstood thatit can, in a. general manner, be

divided into n A steps, A being the number of the letters of the alphabet (English or other alphabet) and it any whole number whatever.

In the example illustrated the letters are arranged according to five concentric crowns or rings, but it is to be understood that, without departing from the scopeof the invention, the number of said concentric crowns or rings can be varied, the angular pitch of the divisions being independent of this number and remaining equal to 360 /nA.

For facilitating the changing of the discs, the dial can be hingedly mounted on its supports in any suitable and removable manner, and the discs can be simply threaded on the pivot H4.

In Figs. 5 to 8, a designates a base at the centre of which is secured a vertical pin b serving as a pivot for the movable disc 0; above the latter a fixed dial or cover (1 is secured by a nut e on the pin b and held stationary by tenons f freely engaged in holes formed in said dial.

In this example, the movable disc is composed of a rigid disc 01 serving as support, of four cryptographic discs 02 c3 c4 c5 of small thickness, for instance made of brass, and of a rigid crown or ring cs; these elements are freely superposed and their relative positions are maintained by means of teno-ns g secured to the disc 01 and freely engaged in holes it formed in the discs 02 to 05 and in the crown or ring cs.

Each of the thin discs is divided into 104 elementary sectors; on the lower disc 02 (Fig. 7) are inscribed 104 groups of 7 letters, occupying all the sectors; the disc ca'is perforated with 26 apertures i uniformly spaced apart each having the width of an elementary sector, and bears groups of 7 letters inscribed either on one edge only of each aperture, or on both edges, or moreover, in the intermediary sectors; the disc 04 is also perforated with 26 apertures 7', but the latter each have the width of '2 elementary sectors, and groups of '7 letters. are inscribed on one edge or on both edges of each'aperture; the disc 05 is perforated with 26 apertures is having a width of three elementary sectors and bears a group of 7 letters on each of the sectors separating the apertures.

Finally, in the fixed dial. dYFig- 6) are cut out apertures m and 11, eachof which has a width of one elementary sector and is separated from the next one by a solid portion having. a triple width. The edges of these apertures are'bevelled in order to facilitate the reading of the cryptographic discs.

The four apertures m, adapted to translate texts, have a total length allowing to read at the same time 26 letters on the movable disc and, in addition, one of. the 104 numbers carried by the crown or ring as opposite its EM reference holes h.

The twoaperturesn, provided for the translation of figures and conventionalsigns, have a total length allowing to read on the movable disc a number of lettersequalto the number of these figuresand signs, for instance 12..

Theletters, figures and signsto be translated are engraved on one edge of these different apertures, in their normal order.

In the crown or ring caareperforated, in addition, tothe holes h, 104 holes. p, equally spaced apart on a. larger circumference,v and serving to operatev the movable disc by means of a point or stylus which the operator moves through a slot q inlthe shape of'an arc of circle providedin the diald. and having. a. length equal,'. for instance,

to about 10 elementary sectors. Owing to a graduation numbered on the edge of said slot the movable disc can thus be rotated to the extent of one or more divisions, either in one direction or in the other at will.

It is to be remembered that the choice of the letters inscribed on the discs c2 c3 c4 05 must be such that, whatever may be the positions of said discs relatively to each other and to the fixed dial, the letters simultaneously appearing in the apertures m are different from each other; the same will then be true for those simultaneously appearing in the apertures n.

I claim:

An enciphering apparatus comprising the combination of a base, a plate pivotally mounted on said base and having registering projections on its upper face, a plurality of discs superposed on said plate and each having a circular series of apertures adapted to engage over said projections, said discs being provided with a series of uniformly spaced radial slots and bearing a plurality of indicia on one edge of each of said slots, said apertures being provided in a number which is a multiple of the number of said slots, a ring-shaped disc placed above the periphery of said discs and having two concentric series of apertures the spacing apart of which corresponds to that of the apertures of said discs, the apertures of the inner series being adapted to engage over said projections, and a non pivoting cover having a plurality of radial slots and bearing on one edge of each of said slots a plurality of letters of the normal alphabet, said cover also having a slot made according to an are extending above the outer series of apertures of said ring-shaped disc.

GUSTAVE GARNIER.

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