Method and apparatus for controlling the operation of a signal decoder in a broadcasting system

• US 6,021,197 A
• Filed: 06/18/1996
• Issued: 02/01/2000
• Est. Priority Date: 06/23/1995
• Status: Expired due to Term

• Current Assignee: Irdeto B.V. (MultiChoice Group Ltd.)
• Original Assignee: Irdeto B.V. (MultiChoice Group Ltd.)
• Inventors: von Willich, Manfred, Rix, Simon Paul Ashley
• Primary Examiner(s): Fuller, Benjamin R.
• Assistant Examiner(s): CLARK, ROBIN C
• Application Number:
  US08/665,605
• Time in Patent Office: 1,323 Days
• Field of Search: 380/4, 380/10, 380/21, 380/23, 380/28, 380/30, 380/25, 380/3, 348/461, 348/467
• US Class Current: 380/212
• 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 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

In a method and apparatus for controlling the operation of a signal decoder in a broadcasting system, a broadcast signal and an encrypted signature are generated and the signature is added to the signal. The signal together with the signature is broadcasted and received in the decoder, where the signature is decrypted and compared with a verification value. If a match occurs, further operation of the decoder is allowed. If a match does not occur, further operation of the decoder is disallowed.

Claims

1. Method for controlling the operation of a signal decoder in a broadcasting system, including the steps of generating a broadcast signal, generating an information table, adding said information table to said signal, generating an encrypted signature from the information in the information table and adding said signature to said signal, wherein said step of generating a broadcast signal includes generating a digital transport stream as a multiplex of a plurality of signal sources, wherein said information table includes identification and control data for the decoder wherein said digital transport stream includes a pay load part, broadcasting said signal with said signature, receiving said signal in said decoder, decrypting said signature, comparing the decrypted signature with information in the information table used as verification value and, if a match occurs, allowing the further operation of said decoder, and, if a match does not occur, disallowing further operation of said decoder.

2. Method according to claim 1 wherein said step of generating an encrypted signature includes reducing the information in the information table through a one-way hash function and encrypting the result of said hash function using a secret key of a public key encryption algorithm, wherein said encrypted signature is decrypted by means of the corresponding public key and said verification value is obtained by reducing the information table in the decoder through said one-way hash function.

3. Method according to claim 2, including the step of storing said information table, wherein the information table includes a list of transport stream identifications, wherein the identification of a transport stream received is compared with the list of identifications of the information table stored and wherein the operation of the decoder is allowed or disallowed in dependence on whether the identification is on the list or not.

4. Method for controlling the operation of a signal decoder in a broadcasting system, including the steps of generating a broadcast signal, generating a first information table from data in said signal, generating an encrypted signature from information in said first information table and adding said signature to said signal, wherein said step of generating a broadcast signal includes generating a digital transport stream as a multiplex of a plurality of signal sources, wherein said digital transport stream includes a pay load part, broadcasting said signal with said signature, receiving said signal in said decoder, generating a second information table in the signal decoder in the same manner as said first information table from data of said received signal decrypting said signature, comparing the decrypted signature with information in the second information table used as verification value and, if a match occurs, allowing the further operation of said decoder, and, if a match does not occur, disallowing further operation of said decoder.

5. Method according to claim 4, wherein said step of generating an encrypted signature includes reducing the information in the first information table through a one-way hash function and encrypting the result of said hash function using a secret key of a public key encryption algorithm, wherein said encrypted signature is decrypted by means of the corresponding public key and said verification value is obtained by reducing the information of said second information table in the decoder through said one-way hash function.

6. Method according to claim 5, wherein said first and second information tables are generated by using a random selection of bits of the pay load part at broadcasting and in the decoder, respectively.

7. Apparatus for controlling the operation of a signal decoder in a broadcasting system, comprising means for receiving a broadcast signal with an encrypted signature, means for decrypting said signature, means for comparing the decrypted signature with a verification value, and means for allowing or disallowing normal operation of said decoder in dependence on the result of this comparison being a match or a mismatch, respectively, wherein said signal includes an information table containing identification and control data, said apparatus further comprising means for storing said information table in said memory, means for using said information table to operate the decoder and means for creating said verification value from information in said information table.

8. Apparatus according to claim 7, comprising a memory for storing a public key, wherein said means for decrypting said signature uses said public key for decrypting said signature.

9. Apparatus according to claim 7, wherein said means for creating said verification value includes means to reduce the information table through a one-way hash function to obtain said verification value.

10. Apparatus according to claim 7, said decoder comprising a descrambler and decompression means, wherein said means for allowing or disallowing operation of said decoder is adapted to enable operation of said descrambler if said signature matches said verification value.

11. Apparatus according to claim 7, comprising means for comparing an identification of a transport stream received with a list of identifications in the information table, wherein said means for allowing or disallowing normal operation of said decoder disallow normal operation if the identification of the transport stream received is not on the list.

12. Apparatus for controlling the operation of a signal decoder in a broadcasting system, comprising means for receiving a broadcast signal with an encrypted signature, means for decrypting said signature, means for comparing the decrypted signature with a verification value, and means for allowing or disallowing normal operation of said decoder in dependence on the result of this comparison being a match or a mismatch, respectively, said apparatus further comprising means for creating a second information table from data of said broadcast signal, and means for creating said verification value from information in said second information table.

13. Apparatus according to claim 12, comprising a memory for storing a public key, wherein said means for decrypting said signature uses said public key for decrypting said signature.

14. Apparatus according to claim 12, wherein said means for creating said verification value includes means to reduce the information table through a one-way hash function to obtain said verification value.

15. Apparatus according to claim 12, said decoder comprising a descrambler and decompression means, wherein said means for allowing or disallowing operation of said decoder is adapted to enable operation of said descrambler if said signature matches said verification value.

16. Apparatus according to claim 12, comprising means for comparing an identification of a transport stream received with a list of identifications in the information table, wherein said means for allowing or disallowing normal operation of said decoder disallow normal operation if the identification of the transport stream received is not on the list.