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. 25, 1994
Filed:
Dec. 18, 1992
Applicant:
Inventors:
Michael Cohen, Jerusalem, IL;
Jonathan Hashkes, Jerusalem, IL;
Assignee:
Other;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04L / ; H04L / ;
U.S. Cl.
CPC ...
380 23 ; 380-9 ; 380 10 ; 380 21 ; 380 22 ; 380 30 ; 380 44 ; 235380 ; 235382 ; 34082531 ; 34082534 ;
Abstract
A system for controlling access to broadcast transmissions including a transmitter having a transmission encoder for scrambling the broadcast, a multiplicity of subscriber receivers, each having an identical receiving decoder, containing no secret cryptographic keys, for descrambling the broadcast and a plurality of selectable and portable executing apparatus each being operatively associatable with a receiving decoder at a partially different given time and each executing generally identical operations to generate a seed for use by the associated receiving decoder to enable the receiving decoder to descramble the broadcast.