Patent ID: 7224798
Filing Date: 2007-05-29
Classification: H04J,H04L,H04N

Abstract:
1. A method for providing an encrypted transport stream, the method comprising the steps of: receiving a clear stream, the clear stream including a plurality of programs, each program comprising a plurality of packets each having a packet identifier (PID), wherein at least one of the plurality of packets is designated a critical packet; scrambling the clear stream according to a first encryption method to provide a first encryption stream; scrambling the clear stream according to a second encryption method to provide a second encryption stream; aligning in time the clear stream, the first encryption stream, and the second encryption stream; after scrambling the clear stream according to the first encryption method to provide the first encryption stream and after scrambling the clear stream according to the second encryption method to provide the second encryption stream, passing packets of the clear stream through a multiplexer, wherein when the at least one critical packet is identified in the packets of the clear stream, the critical packet of the clear stream drops and the scrambled critical packets included in the first and second encryption streams pass; and multiplexing the packets of the clear stream and the critical packets of the first and second encryption streams to provide a partial dual encrypted stream.