System and method for partially encrypted multimedia stream
First Claim
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1. A method for multimedia transmission, comprising:
- generating a copy of a multimedia stream to render first and second clear streams having identical predetermined portions;
sending the first clear stream to a first conditional access (CA) component to encrypt the entire first clear stream to render a completely encrypted stream;
obtaining encrypted versions of the predetermined portions from the completely encrypted stream;
using the second clear stream, encrypting substantially only the predetermined portions using a second CA component to render a partially encrypted stream; and
inserting the encrypted predetermined portions obtained from the completely encrypted stream into the partially encrypted stream to render a transmission stream that is only partially encrypted for transmission thereof.
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Abstract
A multimedia stream head end includes a legacy conditional access (CA) device that fully encrypts the stream using legacy keys. A copy of the stream is sent to a secondary CA device that encrypts only critical packets in the stream using secondary keys to render a partially encrypted stream. The critical packets in the fully encrypted stream from the legacy CA device are obtained and inserted next to the corresponding critical packets in the partially encrypted stream. Thus, only critical packets are encrypted, with encrypted versions being generated by both the legacy CA and secondary CA without the legacy CA knowing which of the packets that it encrypts are “critical”.
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Citations
17 Claims
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1. A method for multimedia transmission, comprising:
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generating a copy of a multimedia stream to render first and second clear streams having identical predetermined portions; sending the first clear stream to a first conditional access (CA) component to encrypt the entire first clear stream to render a completely encrypted stream; obtaining encrypted versions of the predetermined portions from the completely encrypted stream; using the second clear stream, encrypting substantially only the predetermined portions using a second CA component to render a partially encrypted stream; and inserting the encrypted predetermined portions obtained from the completely encrypted stream into the partially encrypted stream to render a transmission stream that is only partially encrypted for transmission thereof. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A system for use in a digital stream transmitter head end having a legacy conditional access (CA) device, comprising:
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at least a system CA device encrypting at least predetermined portions of a first version of a stream; and a reconstitution component combining, into a stream, the predetermined portions from the system CA device and the predetermined portions obtained from a full encryption of a second version of the stream to render a partially encrypted stream having a first encryped version of the predetermined portions and a second encrypted version of the predetermined portions and having substantially no other encrypted data therein, the full encryption being generated by the legacy CA device. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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Specification