Methods and apparatus for providing a partial dual-encrypted stream in a conditional access overlay system
First Claim
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;
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.
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Accused Products
Abstract
The present invention is directed towards providing a partial dual-encrypted stream in a conditional access overlay system. The headend equipment includes an aligner, identifier, and remapper (AIR) device (615) that receives a clear stream and one or two encrypted streams, where the two encrypted streams have been encrypted by two different encryption schemes. The AIR device (615) identifies critical packets associated with the clear stream and subsequently allows two encrypted streams to pass and drops the critical packets of the clear stream. A multiplexer (640) then combines a percentage of the non-critical packets of the clear stream and the critical packets of the two encrypted streams to provide the partial dual-encrypted stream.
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Citations
20 Claims
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1. A method for providing an encrypted transport stream, the method comprising the steps of:
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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;
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. - View Dependent Claims (2, 5, 6, 15)
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- 3. The method of claim l, wherein the aligning step comprises buffering each of the clear stream, the first encryption stream, and the second encryption stream.
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7. A partial dual-encryption device, comprising:
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a port for providing a first encrypted stream from a first scrambler;
a port for providing a second encrypted stream from a second scrambler;
an aligner, identifier, and remapper (AIR) device coupled to each scrambler for providing a partial dual-encrypted stream, wherein a clear stream having at least one critical packet is provided to each scrambler and the AIR device, wherein the AIR device aligns packets of the clear stream, the first encrypted stream, and the second encrypted stream, and wherein, upon identification of the at least one critical packet of the clear stream, provides the partial dual-encrypted stream including non-critical packets of the clear stream, a critical packet of the first encrypted stream, and a remapped critical packet of the second encrypted stream. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A method for transmitting an encrypted transport stream, the method comprising the steps of:
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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 with a first scrambler the clear stream according to a first encryption method to provide a first encrypted stream;
aligning in time the clear stream and the first encrypted stream;
identifying the at least one critical packet associated with the clear stream, wherein prior to identification, packets associated with the clear stream pass to a multiplexer and encrypted packets associated with the first encrypted stream drop, and wherein subsequent to identification, packets associated with the clear stream pass to a second scrambler and encrypted packets associated with the first encrypted stream pass to the multiplexer, wherein the second scrambler provides a second encrypted stream to the multiplexer; and
multiplexing non-critical packets associated with the clear stream and the encrypted critical packets associated with the first and second encrypted streams to provide a partial dual-encrypted stream.
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16. A partial dual-encryption device, comprising:
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a port for providing a first encrypted stream from a first scrambler;
an aligner, identifier, and remapper (AIR) device coupled to the scrambler for providing a partial dual-encrypted stream, wherein a clear stream having at least one critical packet is provided to the scrambler and the AIR device, wherein the AIR device aligns packets of the clear stream and the first encrypted stream, and identifies the at least one critical packet associated with the clear stream, wherein, upon identification of the at least one critical packet, provides the at least one critical packet to a second scrambler, the second scrambler to provide a second encrypted stream, and wherein the AIR device provides the partial dual-encrypted stream including non-critical packets associated with the clear stream and dually-encrypted critical packets associated with the first and second encrypted streams. - View Dependent Claims (17, 18, 19, 20)
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Specification