Patent ID: 7412058
Filing Date: 2008-08-12
Classification: H04H,H04L

Abstract:
1. A digital radio frequency receiver for receiving and deciphering broadcast radio frequency signals containing secure information, the digital radio frequency receiver being a member of a common plurality of radio frequency receivers sharing a predetermined plurality of receiver environmental characteristics, wherein each one of the predetermined plurality of receiver environmental characteristics (1) has a plurality of variations and (2) divides the common plurality of radio frequency receivers into sets of radio frequency receivers based on its own variations, with each such set comprising a plurality of radio frequency receivers and the sets of radio frequency receivers so produced differing from and overlapping those produced by others of the predetermined plurality of receiver environmental characteristics, the digital radio frequency receiver comprising: a data decryption circuit comprising a memory storing a plurality of separately selectable decryption keys, each of the stored decryption keys corresponding to a different one of the receiver environmental characteristics and having a value based on one of the variations of the one of the receiver environmental characteristics as determined by the environment of the digital radio frequency receiver; an input for receiving a radio frequency signal comprising a data stream comprising an encrypted message and a plurality of key selectors, wherein ( the data decryption circuit further comprising a processor configured to select the stored decryption key corresponding to the receiver environmental characteristic identified by each of the key selectors included in the received radio frequency signal and use the selected decryption keys in decrypting the encrypted message, whereby successful decryption of the message occurs only when the variation of each of the receiver environmental characteristics required for decryption of the encrypted message matches the variation of the same corresponding receiver environmental characteristic as determined by the environment of the digital radio frequency receiver.