Source authentication of download information in a conditional access system

• US 6,526,508 B2
• Filed: 12/26/2000
• Issued: 02/25/2003
• Est. Priority Date: 04/03/1995
• Status: Expired due to Term

• Current Assignee: Tech 5 SAS
• Original Assignee: Scientific-Atlanta Incorporated (Cisco Systems, Inc.)
• Inventors: Pinder, Howard G., Banker, Robert O., Wasilewski, Anthony J., Akins, Glendon L. III, Palgon, Michael S.
• Primary Examiner(s): Barrón, Gilberto
• Assistant Examiner(s): Zand, Kambiz
• Application Number:
  US09/748,313
• Publication Number:
  US 20010001014A1
• Time in Patent Office: 791 Days
• Field of Search: 380/232, 380/43, 380/285, 380/30, 713/168, 713/153
• US Class Current: 713/168
• 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 63/04 for providing a confidential data exchange among entities communicating through data packet networks
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 63/0442 wherein the sending and receiving network entities apply asymmetric encryption, i.e. different keys for encryption and decryption cryptographic mechanisms or cryptographic arrangements for public-key encryption H04L9/30
• 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 63/062 for key distribution, e.g. centrally by trusted party cryptographic mechanisms or cryptographic arrangements for key distribution involving a central third party H04L9/0819
• CPC Class Codes: H04L 63/0823 using certificates cryptographic mechanisms or cryptographic arrangements for entity authentication involving certificates H04L9/3263
• CPC Class Codes: H04L 63/12 Applying verification of the received information cryptographic mechanisms or cryptographic arrangements for data integrity or data verification H04L9/32
• CPC Class Codes: H04L 63/123 received data contents, e.g. message integrity
• CPC Class Codes: H04L 63/126 the source of the received data
• 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 21/23476 by partially encrypting, e.g. encrypting 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 21/4405 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

A cable television system provides conditional access to services. The cable television system includes a headend from which service “instances”, or programs, are broadcast and a plurality of set top units for receiving the instances and selectively decrypting the instances for display to system subscribers. The service instances are encrypted using public and/or private keys provided by service providers or central authorization agents. Keys used by the set tops for selective decryption may also be public or private in nature, and such keys may be reassigned at different times to provide a cable television system in which piracy concerns are minimized.

Claims

1. A method for authenticating information in a conditional access cable television system comprising head-end equipment and a plurality of set-top terminals in communication therewith, the head-end equipment including a controller and a plurality of transaction encryption devices associated with a plurality of entitlement agents for providing information to the plurality of set-top terminals, the controller controlling access to the conditional access cable television system, the method comprising:

processing at least a segment of downloadable information provided from a source to generate a digest thereof, wherein the downloadable information includes a logic segment;

associating a source identifier with the downloadable information, wherein the source identifier is associated with the provider providing the downloadable information; and

transmitting a message to at least one set-top terminal, the message including the downloadable information, the digest and the source identifier.

2. The method of claim 1, further including the step of:

using a key to make a processed digest, wherein the key is a private key of a public key-private key pair for the provider of the downloadable information, and wherein the processed digest is included in the transmitted message.

3. The method of claim 2, wherein the digest of the segment of downloadable information is an output of a hash function having the segment of downloadable information as an input to the hash function.

4. The method of claim 2, further including the steps of:

generating the public key-private key pair for the provider of the downloadable information in a transaction encryption device associated with the provider of the downloadable information;

storing the private key in the transaction encryption device associated with the provider of the downloadable information; and

providing the public key for the provider of the downloadable information to at least one set-top terminal in the conditional access cable television system; and

wherein the processed digest is made in the transaction encryption device associated with the provider of the downloadable information.

5. The method of claim 4, wherein the transaction encryption device associated with the provider of the downloadable information is accessible only to the controller.

6. The method of claim 4, wherein the logic segment includes a data segment for use in at least one set-top terminal.

7. The method of claim 4, wherein the logic segment includes a code segment for execution in at least one set-top terminal.

8. The method of claim 4, wherein an entitlement agent that provides a service instance to the conditional access cable television system for display at entitled set-top terminals in the conditional access cable television system is the provider of the downloadable information, and wherein the digest is made in the transaction encryption device associated with the entitlement agent.

9. The method of claim 4, wherein the public key for the provider of the downloadable information is provided to the at least one set-top terminal in a second message transmitted to the at least one set-top terminal.

10. A method for authenticating a message received in a set-top terminal in a conditional access cable television system comprising head-end equipment and a plurality of set-top terminals, the head-end equipment in communication with a plurality of entitlement of agents that provide downloadable information, the method comprising:

storing in a memory of the set-top terminal a public key associated with a provider of downloadable information;

receiving a message having an authentication token and downloadable information, the downloadable information including a logic segment, the authentication token including a processed digest and a source identifier that is associated with the provider of the downloadable information, and wherein the processed digest is a digest of a given portion of the downloadable information that was processed using a private key of a public key-private key pair associated with the provider.

11. The method of claim 10, further including the steps of:

making a first digest using the given portion of the downloadable information;

processing the received processed digest with the public key associated with the provider to make a second digest;

comparing the first digest with the second digest; and

authenticating the source of the downloadable information as the provider associated with the source identifier when the first digest is the same as the second digest.

12. The method of claim 11, wherein the first digest is an output of a hash function having the given portion of the downloadable information as an input to the hash function.

13. The method of claim 11, wherein the memory of the set-top terminal includes a plurality of public keys stored therein;

and prior to the processing step, further including the steps of;

using the source identifier to identify the public key of the provider; and

retrieving the identified public key of the provider from the memory.

14. The method of claim 13, prior to the step of storing a public key, further including the steps of:

receiving a first message at the set-top terminal, the first message including a first public key; and

associating the first public key with the provider of the downloadable information.

19. The method of claim 10, wherein the memory having the public key stored therein is included in a secure element having a processor, and the memory is accessible to only the processor included in the secure element.

15. The method of 11, wherein downloadable information is authenticated as valid when the first digest is the same as the second digest.

16. The method of claim 15, wherein the set-top terminal includes flash memory and a portion of the logic segment is stored in the flash memory after the downloaded information has been authenticated as valid.

17. The method of claim 16, wherein the logic segment included in the downloadable information includes a code segment that is for execution in the set-top terminal, and wherein after the downloadable information has been authenticated as valid the code segment is stored in the flash memory and executed in the set-top terminal.

18. The method of claim 16, wherein the logic segment included in the downloadable information includes a data segment that is for use by an executable code in the set-top terminal, and wherein after the downloadable information has been authenticated as valid the data segment is stored in the flash memory.

20. A set-top terminal that is in communication with head-end equipment included in a cable television system, the head-end equipment comprising a plurality of transaction encryption devices, the set-top terminal comprising:

a port adapted to receive a message having an authentication token from a transaction encryption device of the plurality of transaction encryption devices and downloadable information, the downloadable information including a logic segment, wherein the authentication token includes a processed digest and a source identifier that indicates the provider of the downloadable information;

a memory having at least three public keys stored therein, wherein the at least three public keys includes a first key of a public key-private key pair associated with the set-top, a second key associated with the source identifier and a first transaction encryption device of the plurality of transaction encryption devices, and a third public key associated with a second transaction encryption device of the plurality of transaction encryption devices; and

a processor coupled to the port and the memory, the processor adapted to make a first digest of a first portion of the received downloaded information and to process the received processed digest with the public key associated with source identifier thereby making a second digest, and the processor adapted to compare the first digest with the second digest and authenticate the downloadable information when the first digest and the second digest are the same.

21. The set-top terminal of claim 20, wherein the logic segment of the authenticated downloaded information is stored in a portion of the memory.

22. The set-top terminal of claim 21, wherein the portion of the memory having the logic segment of the authenticated downloadable information stored therein is a flash memory.

23. The set-top terminal of claim 21, wherein the logic segment includes a segment of code that is for execution in the set-top terminal.

24. The set-top terminal of claim 21, wherein the logic segment includes a segment of data that is for use by an executable code in the set-top terminal.

25. The set-top terminal of claim 20, wherein the first digest is an output of a hash function having the first portion of the downloadable information as an input to the hash function.

26. The set-top terminal of claim 20, wherein the memory and the processor are included in a secure element, and the memory is accessible only to the processor of the secure element.

27. An apparatus for providing authenticatable downloadable information to a plurality of set-top terminals in a cable television system, the apparatus comprising:

a transaction encryption device including a digest maker that receives an input and produces a digest therefrom, a key generator that generates a public key-private key pair, a memory having the private key stored therein, and a processor that processes the digest with the private key, and wherein the input to the digest maker includes a logic segment,

a controller adapted to generate a message that includes the logic segment, the processed digest and a source identifier, wherein the source identifier is associated with the public key corresponding to the private key that processed the digest; and

means for providing a secure communication link between the transaction encryption device and the controller.

28. The apparatus of claim 27, wherein the logic segment includes a code segment that is for execution in the at least one set-top terminal.

29. The apparatus of claim 27, wherein the logic segment includes a data segment that is used by an executable code in the at least one set-top terminal.

30. The apparatus of claim 27, wherein the means for providing a secure communication link is a dedicated direct communication link extending between transaction encryption device and the controller, and wherein the transaction encryption device is located in a physically secure area.

31. The apparatus of claim 30, further including:

a second transaction encryption device including a digest maker that receives an input and produces a digest therefrom, a key generator that generates a public key-private key pair, a memory having the private key stored therein, and a processor that processes the digest with the private key, and wherein the input to the digest maker includes a logic sediment, wherein the second transaction encryption device is associated with an entitlement agent that provides service instances to the cable television system, and the second transaction encryption device generates entitlements for the service instances from the first entitlement agent;

wherein the first transaction encryption device further includes a conditional access authority adapted to enable each set-top terminal of the plurality of set-top terminals to process messages associated with the second transaction encryption device, only set-top terminals enabled to process messages from the second transaction encryption device can use the entitlements therefrom to access the service instances provided by the entitlement agent, and further adapted to remove enablement from each enabled set-top terminal, whereby a given set-top terminal having enablement for processing messages associated with the second transaction encryption device removed therefrom can no longer process messages associated with the second transaction encryption device.