On Tuesdays the USPTO issues new patents. Both of today's Spotlight Patents concern aspects of conditional access systems used in satellite and cable TV systems. Apparently assigned to Wegener Communications, the first patent is a reissue patent that concerns the rapid decryption of data by key synchronization and indexing. RE patents are those in which the patent office was asked to reexamine a patent after it has issued in light of prior art that had not been taken into account earlier. Assigned to DirecTV, the second patent concerns techniques for embedded blacklisting for digital broadcast system security.
RE41,919, "Rapid decryption of data by key synchronization and indexing," apparently assigned to Wegener Communications, Inc., a reissue of 7,206,411.
A satellite broadcast conditional access system with key synchronization uses indexing of an authorization stream to quickly restart the decrypting process after short carrier fades and after carrier switches. The authorization stream includes cyphered seeds and index numbers which are sequentially sent to a group of receivers. The same authorization stream can also be broadcast multiple times to the group of receivers. A conditional access server selects a starting index number and increments the index number by a predefined value. The receivers have a memory to save the current index number for the authorization stream. Any receiver that loses its connection to the broadcast and thereafter reestablishes its connection can retrieve the latest index number being issued in the authorization stream and compare it with the stored index number. When the index numbers match or are within a defined threshold, the receiver will continue to decypher the seeds and decrypt the transport stream.
7,835,522,"Embedded blacklisting for digital broadcast system security," assigned to The DIRECTV Group, Inc.
An apparatus and method for transmission security is presented. In one embodiment, the apparatus comprises a receiver communicatively coupleable to an identifiable replaceable conditional access module (CAM) identified by an identification to enable reception of the service, and an authenticator controlling the operability of the receiver according to a comparison between the identification and a list comprising an identification of a plurality of CAMs, wherein the authenticator renders the receiver inoperable according to the comparison.