Conditional access system and method for prevention of replay attacks

• US 8,681,979 B2
• Filed: 10/05/2011
• Issued: 03/25/2014
• Est. Priority Date: 03/02/2000
• Status: Expired due to Fees

• Current Assignee: TiVo Solutions Inc. (Adeia Inc.)
• Original Assignee: TiVo Inc. (Adeia Inc.)
• Inventors: Platt, David C., Goodman, Andrew M., Zenchelsky, Daniel
• Primary Examiner(s): HOFFMAN, BRANDON S
• Application Number:
  US13/253,909
• Publication Number:
  US 20120027208A1
• Time in Patent Office: 902 Days
• Field of Search: None
• US Class Current: 380/210
• CPC Class Codes: H04L 2463/101 applying security measures for digital rights management
• CPC Class Codes: H04L 63/045 wherein the sending and receiving network entities apply hybrid encryption, i.e. combination of symmetric and asymmetric encryption cryptographic mechanisms or cryptographic arrangements using a plurality of keys or algorithms H04L9/14
• CPC Class Codes: H04L 63/10 for controlling access to devices or network resources
• CPC Class Codes: H04N 2005/91364 the video signal being scrambled
• CPC Class Codes: H04N 21/258 Client or end-user data management, e.g. managing client capabilities, user preferences or demographics, processing of multiple end-users preferences to derive collaborative data arrangements for services using the result on the distributing side of broadcast systems H04H60/66; profiles in network data switching protocols H04L67/30
• CPC Class Codes: H04N 21/25891 being end-user preferences retrieval of video data in a video database based on user preferences G06F16/739; arrangements for recognizing users' preferences H04H60/46; user profiles in network data switching protocols H04L67/306; processing of user preferences or user profiles in wireless networks H04W8/18
• CPC Class Codes: H04N 21/4126 The peripheral being portable, e.g. PDAs or mobile phones
• CPC Class Codes: H04N 21/426 Internal components of the client ; Characteristics thereof H04N5/44 takes precedence
• CPC Class Codes: H04N 21/4367 Establishing a secure communication between the client and a peripheral device or smart card
• CPC Class Codes: H04N 21/4622 Retrieving content or additional data from different sources, e.g. from a broadcast channel and the Internet web site content organization and management for information retrieval from the Internet G06F16/958; transmission by internet of broadcast information H04H60/82; stock exchange data over packet-switching network H04L12/1804; push services including data channel over packet-switching network H04L12/1859
• 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 21/47 End-user applications
• CPC Class Codes: H04N 21/4782 Web browsing , e.g. WebTV
• 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 21/816 involving special video data, e.g 3D video
• CPC Class Codes: H04N 21/84 Generation or processing of descriptive data, e.g. content descriptors systems specially adapted for using meta-information in broadcast systems H04H60/73
• CPC Class Codes: H04N 5/782 on tape
• CPC Class Codes: H04N 5/913 for scrambling ; for copy protection
• 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 7/17309 : Transmission or handling of upstream communications

Abstract

In a conditional access system, a headend transmits content to one or more receivers in encrypted transport streams. The system provides a multi-layer security architecture, rendering the system resistant to key replay attacks; if one layer is circumvented, subsequent layers remain intact. A first layer prevents unencrypted keys from being recorded by shielding the unencrypted keys from users and encrypting the path from the receiver'"'"'s conditional access module to the transport decryption module; a second layer prevents a key recorded on one receiver from being played back to the transport decryption module on a second receiver; a third layer prevents a user from decrypting transport streams without the encryption module by encrypting the stream a second time prior to being passed through any user-accessible memory or processor. Event tables are transmitted with the transport stream, either unencrypted for immediate use or encrypted, to prevent unauthorized use.

Claims

1. A method, comprising:

creating, at a headend, an event table for a corresponding transport stream, the event table comprising a location of one or more start codes within the transport stream;

transmitting the transport stream from the headend to at least one receiver among a plurality of receivers;

transmitting the event table from the headend to the at least one receiver among a plurality of receivers.

2. The method of claim 1, wherein the event table further comprises a type of at least one start code of the one or more start codes.

3. The method of claim 1, further comprising:

encrypting the event table prior to transmission with the transport stream.

4. The method of claim 1, wherein the transport stream is an encrypted transport stream, and further comprising:

storing the encrypted transport stream transmitted at the at least one receiver; and

encrypting, at the at least one receiver, the transport stream to obtain a doubly encrypted transport stream;

storing the doubly encrypted transport stream on a storage medium accessible to the at least one receiver.

5. The method of claim 1, wherein at least one start code of the one or more start codes indicates a start of an element in an MPEG stream.

6. The method of claim 1, wherein the transport stream is an encrypted transport stream.

7. A system comprising:

a subsystem, at a headend, implemented at least partially in hardware, that creates an event table for a corresponding transport stream, the event table comprising a location of one or more start codes within the transport stream;

a subsystem, implemented at least partially in hardware, that transmits the transport stream from the headend to at least one receiver among a plurality of receivers;

a subsystem, implemented at least partially in hardware, that transmits the event table from the headend to the at least one receiver among a plurality of receivers.

8. The system of claim 7, wherein the event table further comprises a type of at least one start code of the one or more start codes.

9. The system of claim 7, further comprising:

a subsystem, implemented at least partially in hardware, that encrypts the event table prior to transmission with the transport stream.

10. The system of claim 7, wherein the transport stream is an encrypted transport stream, and further comprising:

a subsystem, implemented at least partially in hardware, that stores the encrypted transport stream transmitted at the at least one receiver; and

a subsystem, implemented at least partially in hardware, that encrypts, at the at least one receiver, the transport stream to obtain a doubly encrypted transport stream;

a subsystem, implemented at least partially in hardware, that stores the doubly encrypted transport stream on a storage medium accessible to the at least one receiver.

11. The system of claim 7, wherein at least one start code of the one or more start codes indicates a start of an element in an MPEG stream.

12. The system of claim 7, wherein the transport stream is an encrypted transport stream.

13. A non-transitory computer readable medium storing instructions which, when executed by one or more processors cause performance of steps comprising:

creating, at a headend, an event table for a corresponding transport stream, the event table comprising a location of one or more start codes within the transport stream;

transmitting the transport stream from the headend to at least one receiver among a plurality of receivers;

transmitting the event table from the headend to the at least one receiver among a plurality of receivers.

14. The computer readable medium of claim 13, wherein the event table further comprises a type of at least one start code of the one or more start codes.

15. The computer readable medium of claim 13, further comprising:

encrypting the event table prior to transmission with the transport stream.

16. The computer readable medium of claim 13, wherein the transport stream is an encrypted transport stream, and further comprising:

storing the encrypted transport stream transmitted at the at least one receiver; and

encrypting, at the at least one receiver, the transport stream to obtain a doubly encrypted transport stream;

storing the doubly encrypted transport stream on a storage medium accessible to the at least one receiver.

17. The computer readable medium of claim 13, wherein at least one start code of the one or more start codes indicates a start of an element in an MPEG stream.

18. The computer readable medium of claim 13, wherein the transport stream is an encrypted transport stream.