Datotek, Inc.

Merlon B Carter

Barrie O Morgan

Kenneth M Branscome

The specification discloses a portable cryptographic device, adapted to be hand-held through solid state electronics, which possesses the capability for enciphering and deciphering plain text. The housing of the device has a keyboard for the input of plain text or cipher text, including numeric characters and control signals and, further, has a display for displaying the inputs. Circuitry within the device is responsive to the inputs and controls the display. Additional circuitry enciphers or deciphers the inputs and substitutes the resulting text into the display. The device incorporates a random code generator for generating a randomized message key which, together with the keyboard inputs, initiates and generates a long sequence of randomized letters for enciphering purposes. In a deciphering mode, a predetermined message key may be entered to set the random code generator at a point to generate the originally entered plain text. Also, a basic key composed of multiple segments fully initializes the random code generator such that more than one device could be used to encipher and decipher text. Similarly, by using different segments of the basic key, varying levels of security can be obtained. Test circuitry is also provided to insure maintenance of the proper key variables and proper operation of the device.

Portable electronic cryptographic device

The specification discloses a digital cryptographic system wherein each of the transmitting and receiving units includes a housing having a front panel. A push-button switch input array is mounted on the front panel, with each push-button switch corresponding to a different number to enable the manual inputting of code variables therethrough. A digital display is provided on the front panel to temporarily display each of the code variables input through the array. Storage circuits are provided to store the code variables input through the array. A switch is provided on the front panel to enable any one of the stored code variables to be selected. A random code generator is operable in response to the selected stored code variables in order to generate a sequence of randomized key digital bits. Circuitry is provided to encipher clear text digital data in a synchronous manner and to transmit enciphered data through a synchronous data link.

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Richardson, TX, United States of America

Merlon B Carter