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REF ID:A27361B 

Cipher Machine (Electro-mechanical) 

Monographic Substitution, Polyalphabetic (Related Sequences) 

Single Circuit Rotor, Reciprocal Wiring, Regular Motion 

Hebern Electric Code Machine 

DEVELOPMENT: 

Invented by Edward H. Hebern, assignor to H and H Patent Developing 

Company of Oakland, California. Application for patent filed in the United 

States, 31 March 1921. Also patented in Great Britain, France, Netherlands, 

Switzerland, Denmark and Norway. 

This is the first of several machines involving circuit rotors patented 

by Hebern, a limited number of which have been manufactured and sold by the 

Hebern Electric Code Company of Oakland, California and its s~ccessor, Internatio...U. Code Machine Company of Reno, Nevada. 

PA.TENTS: 

U. s. 1,510,441 (E. H. Hebern, 30 September 1924, Cl. 197-4). Most 

important features are the details of the circuit rotor design. 

DESCRIPTION: 

. A single circuit-rotor machine used in conjunction with a solenoid 

operated typewriter in which the rotor contacts are wired in complementary 

pairs and the rotor is stepped regularly one position between successive 

encipherments. 

The cipher unit consists essentially of a keyboa~d, a twenty-six point 

circuit rotor between two endplates, and means for stepping the rotor. Each 

endplate is provided with twenty-six equally spaced spring contacts arranged 

in a circle. Each spring contact on the right endplate is connected to a 

keyboard contact of the cipher unit. Each spring contact on the left endplate is connected to one of the electromagnets which, throueh mechanical 

linkages, operate the key levers of an ordinary typewriter. 

The rotor, which is removable from the machine and which rotates on a 

shaft between the two endplates, has twenty-six circular contacts in the 

fonn of flat-headed screws on each of its two faces, corresponding in position 

and spacing to the endplate spring contacts. Each of the fifty-two flat rotor 

contacts is provided with a teminal to which one end of an insulated wire may 

be attached. Tenninals on opposites sides of the rotor are connected by 

twenty-six such wires in complementary pairs. A. normal alphabet is engraved 

around the periphery of the rotor for setting purposes. The rotor is displaced l/26th of a revolution between encipherments by means of a weight and 

pulley arrangement attached to the rotor shaft which operates in conjunction 

with a dog and ratchet wheel. liter a key is depressed, a universal bar 

releases the ratchet dog, thereby allowing the action of the weight to advance 

the rotor one step. 

In order to prevent any sparking due to the movement of the rotor, the 

succession of ope.rations is arranged, by means of a main contact and the 

universal bar action, so that current is supplied to the keyboard. contacts 

onJ...r after such oontact bas been made and is cut off before it has been 

broken; likewise current is cut off from the rotor contacts before the 

stepping action occu.ra. -

@'pp roved for Release by NSA on 09-12-2013 pursuantto E .0. 1352a 
I 

REF ID:A27361B 

By means of a cam geared to the rotor shaft, a lever riding on the 

surface of this cam and a mechanical linkage to the space bar of the typewriter, cipher text is automatically spaced in five-letter groups. No 

provision is made for spacing deciphered plain text or for automatic line 

feed and carriage return on the typewriter (which prints page copy). 

To encipher, a given key on the cipher-unjt keyboard is depresse~, its 

associated contact is closed and a circuit path is completed through the 

rotor to one of the electromagnets which then activates a keylever of the 

typewriter, thus causing the cipher equivalent of the depressed key to be 

printed. The main contact is then opened, current is cut off and the 

rotor is stepped forward one position. The deciphering process is identical 

and, due to the reciprocal wiring of the rotor, no encipher-decipher switch 

is necessary. 

Variable keying elements include the rotor wiring used (which may be 

changed with the aid of a screw-driver), the particular rotor selected from 

a set which is to be provided with the machine, and the initial setting of 

the rotor for a particular message encryption. 

In the patent an alternate version in which characters are printed 

vertically one below the other on a pap er tape (instead of on the usual 

page-printing typewriter) is briefly described. 1be possibility of 

increasing the nwnber of rotors used in the machine is also suggested, but 

no method for moving them .relative to one another is proposed. Though not 

described in the patent, a small keyboard o~erated, non-printing model of 

this machine in which the typewriter is replaced by a bank of signal lamps 

is shown in an advertising brochure and was apparently manufactured under 

the trade name, "Commercial Portable Code". 

(Advertising brochures with photographs and brief descriptions of 

this machine are available in the files of CSGA.S-76C.)