Reliable and non-manipulatable processing of data streams in a receiver

• US 8,599,916 B2
• Filed: 08/26/2010
• Issued: 12/03/2013
• Est. Priority Date: 08/28/2009
• Status: Active Grant

• Current Assignee: Irdeto B.V. (MultiChoice Group Ltd.)
• Original Assignee: Irdeto B.V. (MultiChoice Group Ltd.)
• Inventors: Wajs, Andrew Augustine, Van Foreest, Arnoud Evert, Dekker, Gerard Johan, Curtin, Bruce Victor
• Primary Examiner(s): Kelley, Christopher S
• Assistant Examiner(s): MESSMORE, JONATHAN R
• Application Number:
  US12/869,218
• Publication Number:
  US 20110069222A1
• Time in Patent Office: 1,195 Days
• Field of Search: 375240-241, 375219-222, 348425-426
• US Class Current: 375/240.01
• CPC Class Codes: H04L 63/0435 wherein the sending and receiving network entities apply symmetric encryption, i.e. same key used for encryption and decryption cryptographic mechanisms or cryptographic arrangements for symmetric key encryption H04L9/06
• CPC Class Codes: H04L 65/764 at the destination reformatting of additional data in video clients H04N21/4355
• 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 21/4181 for conditional access
• CPC Class Codes: H04N 21/42623 involving specific decryption arrangements
• CPC Class Codes: H04N 21/4405 involving video stream decryption
• CPC Class Codes: H04N 21/4623 Processing of entitlement messages, e.g. ECM [Entitlement Control Message] or EMM [Entitlement Management Message] arrangements for conditional access to broadcast information or to broadcast-related services H04H60/14
• 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

Abstract

The invention provides a solution for secure and non-manipulatable processing of a data stream in a receiver, possibly in conjunction with a smartcard. A packet identity and a content type identifier associated with the packet identifier are received in encrypted form and securely processed within the receiver to allow an encrypted payload of the data stream to be processed without the possibility to manipulate the content type identifier in an attempt to intercept the payload after decryption.

Claims

1. A method in a receiver for processing a data stream comprising a header and an encrypted payload, the header comprising a first packet identifier, the method comprising:

decrypting the encrypted payload to obtain a decrypted payload;

receiving an encrypted second packet identifier and an encrypted first content type identifier;

obtaining a second packet identifier from the encrypted second packet identifier within a secured environment;

obtaining a first content type identifier associated with the second packet identifier from the encrypted first content type identifier within the secured environment;

comparing the first packet identifier with the second packet identifier to obtain a first comparison result; and

if the first comparison result matches a first predetermined condition, selecting a first decoding module based on the first content type identifier and routing the decrypted payload to the first decoding module for decoding the decrypted payload,

receiving a clear text third packet identifier and a clear text second content type identifier associated with the third packet identifier;

if the first comparison result matches a second predetermined condition, comparing the first packet identifier with the third packet identifier to obtain a second comparison result; and

if the second comparison result matches a third predetermined condition, selecting a second decoding module based on the second content type identifier and routing the decrypted payload to the second decoding module for decoding the decrypted payload.

2. The method according to claim 1, wherein the encrypted second packet identifier and the encrypted first content type identifier are received in one or more encrypted entitlement messages, and wherein the second packet identifier and the first content type identifier are obtained by transmitting the one or more encrypted entitlement messages to a smartcard and receiving the second packet identifier and the first content type identifier from the smartcard over a secure connection.

6. The method according to claim 1, further comprising selecting an interface from a predefined set of interfaces based on the first content type identifier and restricting an output of the first decoding module to the selected interface.

7. The method according to claim 1, wherein

the data stream is an MPEG2 transport stream,

the header and the encrypted payload are part of an elementary stream in the MPEG2 transport stream,

the third packet identifier and the second content type identifier are received in a program map table in the MPEG2 transport stream,

the first decoding module is a video decoder or an audio decoder in a secured chipset of the receiver, and

the second decoding module is a teletext decoder, a subtitling decoder or a software applet and is external to the secured chipset.

3. A method in a receiver for processing a data stream comprising a header and an encrypted payload, the header comprising a first packet identifier for identifying the encrypted payload, the method comprising:

decrypting the encrypted payload to obtain a decrypted payload;

obtaining a second packet identifier from a hardcoded memory within a secured environment;

obtaining a first content type identifier associated with the second packet identifier from the hardcoded memory within the secured environment;

comparing the first packet identifier with the second packet identifier to obtain a first comparison result; and

if the first comparison result matches a first predetermined condition, selecting a first decoding module based on the first content type identifier and routing the decrypted payload to the first decoding module for decoding the decrypted payload;

receiving a clear text third packet identifier and a clear text second content type identifier associated with the third packet identifier;

if the first comparison result matches a second predetermined condition, comparing the first packet identifier with the third packet identifier to obtain a second comparison result; and

if the second comparison result matches a third predetermined condition, selecting a second decoding module based on the second content type identifier and routing the decrypted payload to the second decoding module for decoding the decrypted payload.

4. The method according to claim 3, wherein the hardcoded memory is a part of the receiver.

5. The method according to claim 3, wherein the hardcoded memory is a part of a smartcard.

14. The method according to claim 3, further comprising selecting an interface from a predefined set of interfaces based on the first content type identifier and restricting an output of the first decoding module to the selected interface.

15. The method according to claim 3, wherein

the data stream is an MPEG2 transport stream,

the header and the encrypted payload are part of an elementary stream in the MPEG2 transport stream,

the third packet identifier and the second content type identifier are received in a program map table in the MPEG2 transport stream,

the first decoding module is a video decoder or an audio decoder in a secured chipset of the receiver, and

the second decoding module is a teletext decoder, a subtitling decoder or a software applet and is external to the secured chipset.

8. A receiver for processing a data stream comprising a header and an encrypted payload, the header comprising a first packet identifier, the receiver comprising:

a descrambler configured to decrypt the encrypted payload to obtain a decrypted payload;

a first input module configured to receive an encrypted second packet identifier and an encrypted first content type identifier;

a second input module configured to receive a clear text third racket identifier and a clear text second content type identifier associated with the third packet identifier,

a processor;

a memory; and

a router,

wherein the processor is configured to;

obtain a second packet identifier from the encrypted second packet identifier and obtain a first content type identifier associated with the second packet identifier from the encrypted first content type identifier;

store the second packet identifier and the first content type identifier in the memory;

compare the first packet identifier with the second packet identifier stored in the memory to obtain a first comparison result, a first decoding module being selected if the first comparison result matches a first predetermined condition; and

if the first comparison result matches a second predetermined condition, compare the first packet identifier with the third packet identifier to obtain a second comparison result, a second decoding module being selected if the second comparison result matches a third predetermined condition,

and wherein the router is configured to;

rout the decrypted payload to the first decoding module for decoding the decrypted payload or the second decoding the decrypted payload.

10. The receiver according to claim 8, wherein the processor is further configured to select an interface from a predefined set of interfaces based on the first content type identifier and restrict an output of the first decoding module to the interface.

11. The receiver according to claim 8, further comprising a secured chipset, and wherein the descrambler, the processor, the memory, the router and the first decoding module are parts of the secured chipset.

12. The receiver according to claim 8, wherein

the first input module is configured to receive the second packet identifier and the first content type identifier associated with the second packet identifier from a smartcard over a secure connection.

9. A receiver for processing a data stream comprising a header and an encrypted payload, the header comprising a first packet identifier, the receiver comprising:

a descrambler configured to decrypt the encrypted payload to obtain a decrypted payload;

an input module configured to receive a clear text third racket identifier and a clear text second content type identifier associated with the third packet identifier,

a processor; and

a router,

wherein the processor is configured to;

obtain a second packet identifier and a first content type identifier from a hardcoded memory;

compare the first packet identifier with the second packet identifier stored in the hardcoded memory to obtain a first comparison result, a first decoding module being selected if the first comparison result matches a first predetermined condition;

if the first comparison result matches a second predetermined condition, compare the first packet identifier with the third packet identifier to obtain a second comparison result, a second decoding module being selected if the second comparison result matches a third predetermined condition,

and wherein the router is configured to;

rout the decrypted payload to the first decoding module for decoding the decrypted payload or the second decoding module for decoding the decrypted payload.

13. The receiver according to claim 9, wherein:

the receiver is configured to receive the second packet identifier and the first content type identifier associated with the second packet identifier from a smartcard having a hardcoded memory comprising the second packet identifier and the first content type identifier associated with the second packet identifier, and over a secure connection.

16. The receiver according to claim 9, wherein the processor is further configured to select an interface from a predefined set of interfaces based on the first content type identifier and restrict an output of the first decoding module to the selected interface.

17. The receiver according to claim 9, further comprising a secured chipset, and wherein the descrambler, the processor, the memory, the router and the first decoding module are parts of the secured chipset.