ECM and EMM distribution for multimedia multicast content

• US 20020170053A1
• Filed: 10/26/2001
• Published: 11/14/2002
• Est. Priority Date: 10/26/2000
• Status: Abandoned Application

• Current Assignee: General Instrument Corporation (CommScope Holding Company, Inc.)
• Original Assignee: General Instrument Corporation (CommScope Holding Company, Inc.)
• Inventors: Medvinsky, Alexander, Peterka, Petr, Sprunk, Eric, Moroney, Paul
• Application Number:
  US10/007,520
• Publication Number:
  US 20020170053A1
• Time in Patent Office: Days
• US Class Current: 725/31
• CPC Class Codes: H04N 21/2225 Local VOD servers
• CPC Class Codes: H04N 21/23106 involving caching operations prefetching while addressing of a memory level in which the access to the desired data or data block requires associative addressing means within memory systems or architectures G06F12/0862; caching at an intermediate stage in a data network H04L67/568
• CPC Class Codes: H04N 21/2347 involving video stream encryption
• CPC Class Codes: H04N 21/23473 by pre-encrypting
• CPC Class Codes: H04N 21/2541 Rights Management protecting software against unauthorised usage in a vending or licensing environment G06F21/10; security in data switching network management H04L41/28; security management or policies for network security H04L63/20; access security in wireless networks H04W12/08
• CPC Class Codes: H04N 21/2543 Billing , e.g. for subscription services payment schemes, architectures or protocols G06Q20/00; e-commerce G06Q30/00; arrangements for billing for the use of broadcast information or broadcast-related information H04H60/21
• 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 21/26609 using retrofitting techniques, e.g. by re-encrypting the control words used for pre-encryption
• CPC Class Codes: H04N 21/4143 embedded in a Personal Computer [PC]
• CPC Class Codes: H04N 21/4405 involving video stream decryption
• CPC Class Codes: H04N 21/44204 Monitoring of content usage, e.g. the number of times a movie has been viewed, copied or the amount which has been watched monitoring of user activities for profile generation for accessing a video database G06F16/739; protecting generic digital content where the protection is independent of the precise nature of the content G06F21/10; arrangements for monitoring the use made of the broadcast services in broadcast systems H04H60/31
• CPC Class Codes: H04N 21/4627 Rights management associated to the content security in data switching network management H04L41/28; security management or policies for network security H04L63/20; access security in wireless networks H04W12/08
• CPC Class Codes: H04N 21/47202 for requesting content on demand, e.g. video on demand
• CPC Class Codes: H04N 21/47211 for requesting pay-per-view content payment schemes payment architectures or payment protocols G06Q20/00, G07F
• 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 21/63775 for uploading keys, e.g. for a client to communicate its public key to the server key management H04L9/08; network support of key management H04L63/06
• CPC Class Codes: H04N 21/6405 Multicasting data broadcast and multicast in packet switching networks H04L12/18
• CPC Class Codes: H04N 21/6587 Control parameters, e.g. trick play commands, viewpoint selection
• CPC Class Codes: H04N 21/8355 involving usage data, e.g. number of copies or viewings allowed
• CPC Class Codes: H04N 21/8549 Creating video summaries, e.g. movie trailer retrieval in video databases by using presentations in form of a video summary G06F16/739
• CPC Class Codes: H04N 7/165 : Centralised control of user terminal subsequent to an upstream request signal H04N7/17345; Registering at central by two-way working H04N7/17309
• 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 7/17336 : Handling of requests in head-ends

Abstract

According to one embodiment of the invention, a free preview of a program can be provided to client computers in a multicasting system. This can allow viewers in the multicasting system to view a first portion of the program before deciding whether to order the program content. According to another embodiment, various distribution methods can be accomplished using encryption keys to distribute program content. According to yet another embodiment, an initial viewing period can be provided to allow negotiation of the encryption keys. According to another embodiment, rules and conditions for providing content in a multicasting environment can be utilized.

Claims

1. A method of distributing cryptographic keys in a network comprising a server and a client, said method comprising:

receiving a request for a key from a client;

logging said request for said key in a log;

distributing said key to said client in response to said request;

multicasting program content for decryption by said client utilizing said key;

billing said client based upon said log.

2. The method as described in claim 1 and further comprising not monitoring whether said client requires said key prior to said receiving said request for said key.

3. The method as described in claim 1 wherein said logging said request for said key comprises:

logging a segment of said program content, wherein said key is used for decrypting said segment.

4. The method as described in claim 1 wherein said key is encrypted under a program segment key and wherein said program segment key is distributed to said client in a multicast message.

5. The method as described in claim 4 wherein said distributing said program segment key to said client comprises:

distributing said program segment key as part of a unicast message.

6. The method as described in claim 5 wherein said program segment key is encrypted under a unique key of said client.

7. The method as described in claim 4 wherein said distributing said program segment key to said client comprises:

distributing said program segment key as part of a multicast message.

8. The method as described in claim 7 wherein said program segment key is encrypted under a unique key of said client.

9. The method as described in claim 4 wherein said client is a subscriber to a service and wherein said program segment key is encrypted under a service key.

10. The method as described in claim 9 wherein said service key is distributed to said client in response to said user purchasing said service associated with said service key.

11. The method as described in claim 10 wherein said service key is encrypted under a unique key of said client.

12. The method as described in claim 1 and further comprising:

distributing a next content key in a first message wherein said next content key is encrypted under a first program segment key;

distributing said next content key in a second message wherein said next content key is encrypted under a second program segment key;

wherein said next content key is operable for decrypting a subsequent segment of said program content.

14. The method as described in claim 13 wherein said second key is encrypted utilizing said first key for each of said clients on said list.

15. The method as described in claim 14 wherein said first key is encrypted under a unique key.

16. The method as described in claim 13 and further comprising:

receiving a message from said client indicating that said client is leaving a multicast session.

17. The method as described in claim 16 and further comprising:

removing said client from said list.

18. The method as described in claim 16 and further comprising:

in response to said receiving said message from said client, logging an entry indicating that billing of said client should be stopped for said multicast session.

19. The method as described in claim 17 and further comprising:

distributing a third key to clients remaining on said list so as to prevent said client removed from said list from being able to decrypt a subsequent segment of program content encrypted under said third key.

20. The method as described in claim 13 and further comprising:

receiving a confirmation message from said client confirming that said client received said first key.

21. The method as described in claim 13 and further comprising:

removing said client from said list after a confirmation message is not received within a predetermined period of time after said first key is distributed.

13. A method of distributing cryptographic keys in a multicasting network comprising a server and a client, said method comprising:

receiving from a client a request for a first key;

creating a list of clients that request said first key;

distributing a multicast message to said list of clients that requested said first key so as to distribute a second key, wherein said second key is for use in decrypting encrypted program content.

22. A method of distributing keys in a multicasting network comprising a server and a client, said method comprising:

multicasting encrypted program content;

creating a list of active participants receiving said program, said list of active participants including said client;

receiving a message from said client indicating that said client should remain on said list of active participants;

multicasting a message to said list of active participants, said message including a new key for use in decrypting a subsequent segment of said program content.

23. The method as described in claim 22 wherein said key is encrypted with a key unique to each of said participants listed in said list of participants.

24. The method as described in claim 22 and further comprising:

removing a second client from said list of active participants if a message indicating that said second client should be maintained on said second list of participants is not received from said second client.

26. The method as described in claim 25 and further comprising:

receiving said modified RTP packet at said client.

27. The method as described in claim 25 and further comprising:

removing said fixed field portion from said modified RTP packet so as to recover said RTP packet.

28. The method as described in claim 25 and further comprising:

determining from said fixed field portion whether a key change occurred.

25. A method of transmitting a new encryption key in a network comprising a server and a client, said method comprising:

providing a packet for use as an RTP packet comprising a payload portion and a header portion;

inserting a field in said RTP packet operable to indicate key changes to said client so as to create a modified RTP packet;

transmitting said modified RTP packet to said client.

29. A method of transmitting a new encryption key in a network comprising a server and a client, said method comprising:

providing a packet for use as an RTP packet comprising a header portion;

utilizing a padding bit in said header portion to indicate key changes to said client.

30. A method of multicasting new encryption keys to a plurality of clients, said method comprising:

providing a first key for use by a first client;

encrypting said first key;

providing a second key for use by a second client;

encrypting said second key;

combining said encrypted first key and said encrypted second key as part of a message;

multicasting said message to said plurality of clients so as to allow said first client to obtain said encrypted first key and said second client to obtain said encrypted second key.

31. The method as described in claim 30 wherein said combining comprises concatenating said encrypted first key and said encrypted second key in said message.

32. The method as described in claim 30 wherein said first key and said second keys are program keys.