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:
Aug. 23, 1994
Filed:
Dec. 02, 1992
Anthony J Wasilewski, Alpharetta, GA (US);
Keith Gammie, Markham, CA;
Scientific Atlanta, Inc., Atlanta, GA (US);
Abstract
In a data transmission system comprising a plurality N of transmission sites and at least one reception site, a set of data at each transmission site is uniquely encrypted by (a) providing each transmission site with a broadcast key unique to that transmission site and a system key that is the same for all transmission sites, the system key comprising a plurality S of bits and each of the broadcast keys comprising a unique plurality B of bits, wherein B is less than S; (b) convolving in a predetermined manner at each transmission site the system key and the broadcast key unique to that transmission site to generate a unique data encryption key for that transmission site; (c) encrypting the set of data at each transmission site with the unique data encryption key generated at that site. The sets of data uniquely encrypted at each transmission site are then transmitted to the reception site. There is stored, in a memory at the reception site, the system key and the of said broadcast keys to enable a selected one of the encrypted sets of data to be decrypted at the reception site. The memory capacity necessary to store the system key and the broadcast keys at the reception site is no greater than ((N.times.B)+S) bits. Alternatively, a plurality N of data sets at a single transmission site are encrypted in this manner.