Elementary stream partial encryption
First Claim
1. A method of encrypting a television signal, comprising:
- encrypting an audio portion of the television signal according to a first encryption method to produce a first encrypted audio portion and according to a second encryption method to produce a second encrypted audio portion; and
combining an unencrypted video portion of the television signal with the first and second encrypted audio portion.
2 Assignments
0 Petitions
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. In one embodiment, only audio data are encrypted leaving video in the clear. 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.
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Citations
82 Claims
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1. A method of encrypting a television signal, comprising:
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encrypting an audio portion of the television signal according to a first encryption method to produce a first encrypted audio portion and according to a second encryption method to produce a second encrypted audio portion; and
combining an unencrypted video portion of the television signal with the first and second encrypted audio portion. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of encrypting a television signal, comprising:
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encrypting an audio portion of the television signal according to a first encryption method to produce a first encrypted audio portion; and
combining the first encrypted audio portion with an unencrypted video portion of the television signal to produce a partially encrypted television signal. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21)
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22. An encrypted television signal for encrypting a television signal having a clear audio portion and a clear video portion, comprising:
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a first encrypted audio portion, comprising the clear audio portion encrypted under a first encryption method;
a second encrypted audio portion, comprising the clear audio portion encrypted under a second encryption method; and
an unencrypted video portion. - View Dependent Claims (23, 24)
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25. An encrypted television signal for encrypting a television signal having a clear audio portion and a clear video portion, comprising:
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a first encrypted audio portion, comprising the clear audio portion encrypted under a first encryption method; and
an unencrypted video portion. - View Dependent Claims (26, 27, 29)
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28. A television set-top box, comprising:
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a receiver receiving a dual partially encrypted television program;
a decrypter that receives encrypted audio packets from the receiver and decrypts the encrypted audio packets, the encrypted audio packets being encrypted under a first encryption algorithm; and
a decoder that receives and decodes the decrypted audio packets, and that receives and decodes unencrypted video packets to produce a television signal suitable for play on a television receiver.
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30. A cable system headend, comprising:
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a first encryption system that encrypts audio packets using a first encryption algorithm;
a second encryption system that encrypts audio packets using a second encryption algorithm; and
means for distributing a stream of packets over a cable television system, the stream of packets comprising a video packets, audio packets encrypted under the first encryption algorithm, and audio packets encrypted under the second encryption algorithm and system information packets. - View Dependent Claims (31, 32, 33, 34)
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35. A method of decoding a partially encrypted television signal, comprising:
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receiving a television signal having an encrypted audio portion and a clear video portion;
decrypting the encrypted audio portion to produce a decrypted audio portion;
decoding the decrypted audio portion and the clear video portion to produce a decoded television signal. - View Dependent Claims (36, 37, 38, 39, 40, 41, 42, 43, 44, 45)
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46. A method of decoding a partially encrypted television signal, comprising:
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receiving a television signal having a first encrypted audio portion, a second encrypted audio portion and a clear video portion, the first audio portion being identified by a first packet identifier (PID), and the second audio portion being identified by a second PID;
discarding the second encrypted audio portion by PID filtering;
decrypting the first encrypted audio portion to produce a decrypted audio portion; and
decoding the decrypted audio portion and the clear video portion to produce a decoded signal. - View Dependent Claims (47, 48, 49, 50, 51, 52, 53)
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54. A method of encrypting a digital television signal, wherein the television signal includes an elementary data stream and system information (SI), comprising:
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encrypting the SI under a first encryption system;
forming a partially encrypted digital television signal comprising;
the elementary data stream in an unencrypted form; and
the SI encrypted under the first encryption system. - View Dependent Claims (55, 56, 57, 58, 59, 60, 61, 62)
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63. A partially encrypted digital television signal, comprising:
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an unencrypted elementary data stream; and
system information (SI) encrypted under a first encryption system. - View Dependent Claims (64, 65, 66)
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67. A television set-top box, comprising:
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a receiver that receives a television signal comprising content and encrypted system information;
a decrypter that decrypts the system information; and
a decoder that decodes the content. - View Dependent Claims (68, 69, 70, 71)
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72. A method of encrypting a television signal, comprising:
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encrypting an elementary stream of the television signal according to a first encryption method to produce a first encrypted elementary stream; and
encrypting the elementary stream according to a second encryption method to produce a second encrypted elementary stream. - View Dependent Claims (73, 74, 75)
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76. A method of encrypting a television signal, comprising:
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encrypting a selected elementary stream of the television signal according to a first encryption method to produce a first encrypted elementary stream; and
combining the first encrypted elementary stream with at least one unencrypted elementary stream of the television signal to produce a partially encrypted television signal. - View Dependent Claims (77, 78, 79, 80, 81, 82)
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Specification