METHODS AND APPARATUS FOR PROVIDING A PARTIAL DUAL-ENCRYPTED STREAM IN A CONDITIONAL ACCESS OVERLAY SYSTEM

• US 20070286417A1
• Filed: 04/24/2007
• Published: 12/13/2007
• Est. Priority Date: 04/03/1995
• Status: Active Grant

• Current Assignee: Tech 5 SAS
• Original Assignee: Scientific-Atlanta LLC (Cisco Systems, Inc.)
• Inventors: Pinder, Howard, Wasilewski, Anthony, Evans, Jonathan, Woodward, William
• Granted Patent: US 7,805,399 B2
• Time in Patent Office: Days
• US Class Current: 380/37
• CPC Class Codes: H04J 2203/008 Support of video
• CPC Class Codes: H04L 2463/101 applying security measures for digital rights management data processing systems or methods, specially adapted for commerce, e.g. marketing, shopping, billing, auctions or e-commerce G06Q30/00
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 63/0478 applying multiple layers of encryption, e.g. nested tunnels or encrypting the content with a first key and then with at least a second key cryptographic mechanisms or cryptographic arrangements using a plurality of keys or algorithms H04L9/14
• CPC Class Codes: H04N 21/2265 Server identification by a unique number or address, e.g. serial number network arrangements, protocols or services for addressing or naming H04L61/00
• CPC Class Codes: H04N 21/2347 involving video stream encryption
• CPC Class Codes: H04N 21/23476 by partially encrypting, e.g. encrypting the ending portion of a movie
• CPC Class Codes: H04N 21/23608 Remultiplexing multiplex streams, e.g. involving modifying time stamps or remapping the packet identifiers
• CPC Class Codes: H04N 21/23897 by partially encrypting, e.g. encrypting only the ending portion of a movie
• CPC Class Codes: H04N 21/26606 for generating or managing entitlement messages, e.g. Entitlement Control Message [ECM] or Entitlement Management Message [EMM] arrangements for conditional access to broadcast information or to broadcast-related services H04H60/14
• CPC Class Codes: H04N 21/426 Internal components of the client ; Characteristics thereof H04N5/44 takes precedence
• CPC Class Codes: H04N 21/43607 Interfacing a plurality of external cards, e.g. through a DVB Common Interface [DVB-CI]
• CPC Class Codes: H04N 21/4405 involving video stream decryption
• CPC Class Codes: H04N 21/4524 involving the geographical location of the client retrieval from the Internet by querying based on geographical locations G06F16/9537; systems specially adapted for using geographical information in broadcast systems H04H60/70; protocols in which the network application is adapted for the location of the user terminal in communication control or processing H04L67/52; services making use of the location of users or terminals in wireless networks H04W4/02; locating users or terminals in wireless networks H04W64/00
• CPC Class Codes: H04N 21/63345 by transmitting keys key distribution for secret or secure communication H04L9/08; network support of key management H04L63/06
• CPC Class Codes: H04N 7/162 Authorising the user terminal, e.g. by paying; Registering the use of a subscription channel, e.g. billing
• CPC Class Codes: H04N 7/163 by receiver means only
• CPC Class Codes: H04N 7/1675 Providing digital key or authorisation information for generation or regeneration of the scrambling sequence pseudo-random number generators in general G06F7/58
• CPC Class Codes: H04N 7/17354 in an intermediate station common to a plurality of user terminals

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.

Claims

1. A method comprising:

receiving a clear stream of packets including a critical packet;

scrambling the clear stream of packets according to a first encryption method to provide a first encryption stream;

scrambling the clear stream of packets 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 multiplexer, the critical packet of the clear stream is removed from the clear stream and is replaced with the associated scrambled critical packets included in the first and second encryption streams; and

multiplexing the remaining packets of the clear stream and the replacement critical packets of the first and second encryption streams to provide a partial dual encrypted stream.

2. The method of claim 1, further comprising remapping a PID value associated with the second encryption stream, whereby the scrambled packets of the first and second encryption streams each have a differing PID value.

3. The method of claim 1, wherein the aligning step comprises buffering each of the clear stream, the first encryption stream, and the second encryption stream.

4. The method of claim 3, wherein the aligning step further comprises:

searching the clear stream for a reference packet; and

comparing the reference packet with packets in the first encryption stream and the second encryption stream, wherein the packets associated with the clear stream pass and the packets associated with the first and second encryption streams drop until the packets associated with the first and second encryption streams match the reference packet.

5. The method of claim 1, further comprising demultiplexing each of the clear stream and the first and second encryption streams to provide a plurality of programs.

6. The method of claim 5, wherein a common program demultiplexed from each stream is provided to a common aligner, identifier, and remapper device.

7. A computer readable medium for storing software for performing a method, the computer readable medium comprising:

logic configured to receive a clear stream of packets including at least one critical packet;

logic configured to scramble the clear stream of packets according to a first encryption method to provide a first encryption stream;

logic configured to scramble the clear stream of packets according to a second encryption method to provide a second encryption stream;

logic configured to align in time the clear stream, the first encryption stream, and the second encryption stream;

logic configured to pass packets of the clear stream through a multiplexer,

logic configured to removed the critical packet of the clear stream from the clear stream when the critical packet is identified in the multiplexer,

logic configured to replace the critical packet of the clear stream with the associated scrambled critical packets included in the first and second encryption streams; and

logic configured to multiplex the remaining packets of the clear stream and the replacement critical packets of the first and second encryption streams to provide a partial dual encrypted stream.

8. The computer readable medium of claim 7, further comprising logic configured to remap at least one PID value associated with the second encryption stream, whereby the scrambled packets of the first and second encryption streams each have a differing PID value.

9. The computer readable medium of claim 7, wherein logic configured to align in time the clear stream comprises logic configured to buffer each of the clear stream, the first encryption stream, and the second encryption stream.

10. The computer readable medium of claim 9, wherein logic configured to align in time the clear stream further comprises:

logic configured to search the clear stream for a reference packet;

logic configured to compare the reference packet with packets in the first encryption stream and the second encryption stream,

logic configured to pass the packets associated with the clear stream; and

logic configured to drop the packets associated with the first and second encryption streams until the packets associated with the first and second encryption stream match the reference packet.

11. The computer readable medium of claim 7, further comprising logic configured to demultiplex each of the clear stream and the first and second encryption streams to provide a plurality of programs.

12. The computer readable medium of claim 11, further comprising logic configured to provide a common program demultiplexed from each stream to a common aligner, identifier, and remapper device.