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:
Jul. 12, 1988
Filed:
May. 20, 1986
Applicant:
Inventors:
Norbert Erbes, Karlsruhe, DE;
Dietrich Rother, Tamm, DE;
Assignee:
Alcatel N.V., Amsterdam, NL;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04L / ;
U.S. Cl.
CPC ...
380 48 ; 380 44 ; 380 28 ;
Abstract
A system for encrypted information transmission is disclosed in which so-called recording interference is suppressed. Encryption is effected by means of a periodically recurring pseudo-noise sequence (key word). Synchronization between transmitter and receiver is produced by means of a sync word. During the period of validity of the key word, each sync word is used only once. At least the sync words already used or the information derived therefrom are stored in a sync-word memory (SP). If a sync word appears twice, this indicates recording interference, and the associated information is suppressed.