The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 26, 1982
Filed:
Oct. 23, 1979
Walter R Widmer, Niederhasli, CH;
Gretag Aktiengesellschaft, Regensdorf, CH;
Abstract
An encipher-decipher apparatus including an input keyboard and a processing and control stage which enciphers or deciphers data received directly from the keyboard or preferably from a text store with the aid of a cipher generator. The cipher generator produces a cipher sequence dependent on two code data items that determine the initial state of the cipher generator. One item for encryption is supplied as a set of random code characters from a random generator. The random generator comprises a continually cycled modulo-n counter and a FIFO memory into which the instantaneous state of the counter is entered at each of successive actuations of keys of the keyboard, such key operations being those done in any event in the use of the apparatus. The cycle time of the counter is much less than the time between consecutive key operations. A clock rate of 100 kHz is suggested. The set of characters is read out of the FIFO store at the start of data processing for use by the cipher generator.