Partial encryption and PID mapping
First Claim
1. An encrypted television signal, comprising:
- a plurality of encrypted samples of the television program, the samples being encrypted under a first encryption method; and
an unencrypted portion.
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Accused Products
Abstract
An encryption arrangement for multiple encryption of television programs. A system according to embodiments of the present invention multiple encrypts only a portion of the data required for full presentation of a television program to permit coexistence of multiple conditional access encryption systems associated with multiple manufacturer'"'"'s set-top boxes within a single system. PID mapping techniques are used to distinguish between multiple encryptions. By only encrypting a portion of the program, dramatically less bandwidth is consumed than the alternative of multiple encryption of all program data, thus permitting a larger number of programs to be carried over the same bandwidth while permitting coexistence of multiple conditional access systems in a single cable television system.
387 Citations
67 Claims
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1. An encrypted television signal, comprising:
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a plurality of encrypted samples of the television program, the samples being encrypted under a first encryption method; and
an unencrypted portion. - View Dependent Claims (2, 3, 4, 5)
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6. An encrypted television program, comprising:
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a plurality of unencrypted packets; and
a plurality of encrypted packets, wherein both the unencrypted and the encrypted packets are required to decode the television program. - View Dependent Claims (7, 8, 9)
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10. A method of encrypting content, comprising:
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identifying a portion of the content to encrypt according to a selection algorithm where less than 100% of the content is encrypted;
encrypting the identified content portion according to a first encryption method to produce a first encrypted content portion;
encrypting the identified content according to a second encryption method to produce a second encrypted content portion; and
combining an unencrypted content portion along with the first and second encrypted content portions to produce partially dual encrypted content. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. A method of encrypting content, comprising:
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encrypting content according to a first encryption method to produce a first encrypted content portion; and
combining the first encrypted content portion with an unencrypted content portion to produce partially encrypted content. - View Dependent Claims (31, 32)
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33. A method of managing multiple access control systems within an audio visual content distribution system, comprising:
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identifying a portion of the content to replicate for each of a plurality of access control systems according to a selection algorithm wherein less than 100% of the content is replicated; and
replicating the identified portion. - View Dependent Claims (34, 35, 36, 37, 38, 39)
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40. A method of encoding a packetized digital television signal comprising:
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encrypting a portion of the packets containing the digital television signal according to a first encryption algorithm;
encrypting the portion of the packets containing the digital television signal according to a second encryption algorithm;
leaving a portion of the packets containing the digital television signal unencrypted;
assigning a primary packet identifier to the unencrypted packets;
assigning a primary packet identifier to the packets encrypted under the first encryption algorithm; and
assigning a secondary packet identifier to the packets encrypted under the second encryption algorithm. - View Dependent Claims (41, 42, 43)
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44. A packet selector and duplicator device, comprising:
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input means for receiving a stream of clear packets from a satellite descrambler;
means for selecting a group of packets for dual encryption while leaving a remaining set of clear packets;
means for duplicating the selected packets to provide a first and second set of duplicate packets;
means for assigning a first packet identifier to the first set of duplicate packets and assigning a second packet identifier to the second set of duplicate packets;
means for multiplexing the first set of duplicate packets and the second set of duplicate packets with the set of clear packets to produce an output stream of packets. - View Dependent Claims (45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55)
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56. A packet identifier remapping apparatus, comprising:
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a demodulator that demodulates a stream of modulated packets, the stream of packets comprising clear packets with a first packet identifier, encrypted packets with a second packet identifier and packets with a third packet identifier; and
a remapper that changes the packet identifiers so that the clear packets with the first packet identifier and the encrypted packets with the second packet identifier have the same packet identifier. - View Dependent Claims (57, 58, 59, 60, 61, 62)
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63. A method carried out at a television provider headend, comprising:
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receiving a feed of scrambled television content in the form of a stream of packets;
descrambling the scrambled television content to produce a stream of clear packets;
selecting a packet for dual encryption;
duplicating the packet to provide first and second packets;
re-mapping the first and second packets to first and second packet identifiers;
encrypting the first packet under a first encryption algorithm to produce a first encrypted packet;
encrypting the second packet under a second encryption algorithm to produce a second encrypted packet;
re-mapping clear packets to the first packet identifier. - View Dependent Claims (64, 65, 66, 67)
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Specification