CA system for broadcast DTV using multiple keys for different service providers and service areas

• US 20020146125A1
• Filed: 09/25/2001
• Published: 10/10/2002
• Est. Priority Date: 03/14/2001
• Status: Abandoned Application

• Current Assignee: Thomson Licensing SA (Vantiva SA)
• Original Assignee: Thomson Licensing SA (Vantiva SA)
• Inventors: Virag, David Emery, Duffield, David Jay, Deiss, Michael Scott, Eskicioglu, Ahmet, Beyers, Billy Wesley
• Application Number:
  US09/962,970
• Publication Number:
  US 20020146125A1
• Time in Patent Office: Days
• US Class Current: 380/255
• CPC Class Codes: H04L 2209/601 Broadcast encryption
• CPC Class Codes: H04L 9/0825 using asymmetric-key encryption or public key infrastructure [PKI], e.g. key signature or public key certificates
• CPC Class Codes: H04L 9/083 involving central third party, e.g. key distribution center [KDC] or trusted third party [TTP]
• CPC Class Codes: H04N 21/26613 for generating or managing keys in general key distribution for secret or secure communication involving central third party, e.g. key distribution center [KDC] or trusted third party [TTP] H04L9/083; network support of key management H04L63/06; key management for network security in communication control or processing H04W12/04
• CPC Class Codes: H04N 21/4181 for conditional access
• 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 21/4516 involving client characteristics, e.g. Set-Top-Box type, software version or amount of memory available
• 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 21/454 Content or additional data filtering, e.g. blocking advertisements
• CPC Class Codes: H04N 7/163 by receiver means only
• 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

Abstract

A method for managing access to scrambled broadcast or transmitted events received from a variety of service providers (including broadcast television networks, cable television networks, digital satellite systems). In one preferred embodiment, each service provider employs a different public key for encrypting the access information message, and each smart card includes the corresponding private keys for the public keys, thereby permitting a user to access events from various service providers without changing the smart card.

Claims

1. A method for managing access to a restricted transmitted event, said method comprising:

(a) receiving at least one first transmitted event from a first service provider, said transmitted event being scrambled;

(b) receiving at least one second transmitted event from a second service provider, said transmitted event being scrambled;

(c) receiving encrypted access information associated with said transmitted events, said access information including first and second descrambling keys, said first descrambling key corresponding to said first service provider and said second descrambling key corresponding to said second service provider;

(d) decrypting said access information; and

,

(e) descrambling said transmitted events.

2. The method of claim 1 wherein the steps of decrypting and descrambling are performed in a smart card, said encrypted access information being encrypted using respective first and second public keys and being decrypted using a corresponding respective first and second private keys stored in said smart card.

3. The method of claim 1 wherein the steps of decrypting and descrambling are performed in a smart card, said encrypted access information being encrypted using respective first and second symmetric keys and being decrypted using a corresponding respective first and second symmetric keys stored in said smart card.

4. The method of claim 1 wherein said smart card comprises a card body with a plurality of terminals arranged on a surface of said card body in accordance with one of ISO 7816 and PCMCIA card standards.

5. The method of claim 1, wherein the first service provider'"'"'s broadcast area is adjacent to the second service provider'"'"'s broadcast area.

6. The method of claim 1, wherein the first service provider'"'"'s broadcast area is overlapping with respect to the second service provider'"'"'s broadcast area.

7. A method for allowing a digital video apparatus to manage access to a restricted transmitted event comprises the steps of:

(a) receiving, from a first service provider, access information encrypted using a first public key, said access information including a first encrypted event key;

(b) receiving, from a second service provider, access information encrypted using a second public key, said access information including a second encrypted event key;

(c) passing said first and second event keys to a smart card coupled to said digital video apparatus;

(d) receiving a first transmitted event from said first service provider, said first transmitted event being scrambled using said first event key;

(e) receiving a second transmitted event from said second service provider, said second transmitted event being scrambled using said second event key; and

,

(f) decrypting, in said smart card, one of said first and second encrypted event keys.

8. The method of claim 7, comprising the further steps of:

(g) passing at least one of said first and second transmitted events to said smart card;

(h) descrambling, in said smart card, one of said first and second transmitted events using said one of said first and second event keys; and

(i) passing said descrambled transmitted event to said digital video apparatus.

9. A conditional access system comprising:

at least two program service providers; and

,

at least one digital device for receiving scrambled transmitted signals from the at least two service providers, said digital device including at least one smart card for descrambling said scrambled transmitted signals, wherein said at least one smart card includes at least two decryption keys for decrypting at least two respective descrambling keys, said descrambling keys being used to descramble the transmitted signals received from the at least two service providers.

10. The conditional access system of claim 9, wherein the at least two decryption keys comprise at least two private keys.

11. The conditional access system of claim 9, wherein the at least two decryption keys comprise at least two symmetric keys.

12. The conditional access system of claim 9, wherein a first of the at least two service providers scrambles signals using a first scrambling key encrypted by a first public key, and a second of the at least two service providers scrambles signals using a second scrambling key encrypted by a second public key, such that a first of the at least two private keys is used to recover the first scrambling key and descramble the signals of the first service provider, and a second of the at least two private keys is used to recover the second scrambling key and descramble the signals of the second service provider.

13. The conditional access system of claim 9, wherein a first of said at least two service providers is disposed in a first geographic region, and a second of said at least two service providers is disposed in a second geographic region adjacent to, but different from, said first geographic region.

14. The conditional access system of claim 9, wherein a first of said at least two service providers is disposed in a first broadcast region, and a second of said at least two service providers is disposed in a second broadcast region adjacent to, but different from, said first broadcast region.

15. A method for managing access to a plurality of restricted transmitted events, said method comprising:

(a) receiving a plurality of transmitted events from a plurality of different service providers, said transmitted events being scrambled;

(b) receiving encrypted access information from the plurality of different service providers associated with said plurality of transmitted events, said access information comprising a plurality of descrambling keys, each of said plurality of descrambling keys corresponding to each of said plurality of service providers;

(c) decrypting said access information; and

,

(d) descrambling said plurality of transmitted events.

16. A method for providing conditional access, comprising the steps of:

(a) assigning a first key pair to a first geographic region;

(b) assigning a second key pair to a second geographic region different from said first geographic region;

(c) permitting a broadcaster within the first geographic region to use a public key of said first scrambling key pair to encrypt at least one descrambling key;

(d) permitting a broadcaster within the second geographic region to use a public key of said second scrambling key pair to encrypt at least one descrambling key;

(e) providing a private key of said first scrambling key pair and a private key of said second scrambling key pair in a digital device; and

(f) permitting a user conditional access to said scrambled transmitted signals from said first and second geographic regions by utilizing the private keys provided in the digital device.

17. A method for managing access to a restricted transmitted event, said method comprising:

(a) receiving at least one first transmitted event from a first service provider, said transmitted event being scrambled;

(b) receiving at least one second transmitted event from a second service provider, said transmitted event being scrambled;

(c) receiving access information associated with said transmitted events;

(d) deriving first and second descrambling keys from said access information, said first descrambling key corresponding to said first service provider and said second descrambling key corresponding to said second service provider; and

,

(e) descrambling said transmitted events using said first and second descrambling keys.