Method and system for encrypting and decrypting a transport stream using multiple algorithms

• US 8,213,602 B2
• Filed: 11/27/2006
• Issued: 07/03/2012
• Est. Priority Date: 11/27/2006
• Status: Expired due to Fees

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Mamidwar, Rajesh
• Primary Examiner(s): MOORTHY, ARAVIND K
• Application Number:
  US11/606,305
• Publication Number:
  US 20080123859A1
• Time in Patent Office: 2,045 Days
• Field of Search: 380/28, 380/201, 380/210, 380/223, 380/239, 380/255, 713/150, 713/163, 713/165, 713/189, 726/26, 705/50, 705/51, 705/57
• US Class Current: 380/28
• CPC Class Codes: H04L 9/0625 with splitting of the data block into left and right halves, e.g. Feistel based algorithms, DES, FEAL, IDEA or KASUMI
• CPC Class Codes: H04L 9/0631 Substitution permutation network [SPN], i.e. cipher composed of a number of stages or rounds each involving linear and nonlinear transformations, e.g. AES algorithms
• CPC Class Codes: H04L 9/0827 involving distinctive intermediate devices or communication paths network architectures or network communication protocols using different networks H04L63/18

Abstract

There is provided a method for encrypting a data stream using multiple algorithms. In one embodiment, a first portion of the data stream is encrypted with a first algorithm utilizing a first key to generate a first encrypted portion. The first algorithm can be, for example, a Triple Data Encryption Algorithm (TDEA). Data indicating the first algorithm and the first key is then transmitted. Then, the first encrypted portion of the data stream is transmitted. Thereafter, a second portion of the data stream is encrypted with a second algorithm utilizing a second key to generate a second encrypted portion. The second algorithm can be, for example, a Single Data Encryption Algorithm (SDEA). Next, data indicating the second algorithm and the second key is transmitted. Thereafter, the first encrypted portion of the data stream is transmitted.

Claims

1. A method for encrypting a data stream including a video content, said method comprising:

encrypting a first portion of said video content of said data stream with a first encryption algorithm utilizing a first key to generate a first encrypted portion, wherein said first portion is defined by a first pre-determined period of time and spans for said first pre-determined period of time;

transmitting data indicating said first encryption algorithm and said first key;

transmitting said first encrypted portion;

changing said first encryption algorithm to a second encryption algorithm after said first pre-determined period of time;

encrypting a second portion of said video content of said data stream with said second encryption algorithm utilizing said first key to generate a second encrypted portion, wherein said second portion is defined by a second pre-determined period of time and spans for said second pre-determined period of time;

transmitting data indicating said second encryption algorithm;

transmitting said second encrypted portion;

changing said first key to a second key;

encrypting a third portion of said video content of said data stream with said second encryption algorithm utilizing said second key to generate a third encrypted portion, wherein said third portion is defined by a third pre-determined period of time and spans for said third pre-determined period of time;

transmitting data indicating said second key;

transmitting said third encrypted portion.

2. The method of claim 1 wherein said first, second and third encrypted portions comprise respective first, second and third pluralities of encrypted transport packets, wherein a first parity of said first key is included in each of said first and second plurality of encrypted transport packets, and a second parity of said second key is included in each of said third plurality of encrypted transport packets.

3. The method of claim 1 wherein each of said first pre-determined period of time and said second pre-determined period of time is ten seconds.

4. The method of claim 1 wherein said first and second encryption algorithms is each one of a Single Data Encryption Algorithm (SDEA), a Triple Data Encryption Algorithm (TDEA), a Common Scrambling Algorithm (CSA), or an Advanced Encryption Standard (AES) Algorithm.

5. The method of claim 1 wherein said data indicating said first encryption algorithm and said first key, said data indicating said second encryption algorithm and said data indicating said second key are transmitted through a different channel than said first, second and third encrypted portions.

6. The method of claim 1 wherein said data indicating said first encryption algorithm and said first key is included in a first key packet.

7. A method for decrypting an encrypted video content of a data stream, said method comprising:

receiving data indicating a first encryption algorithm and a first key;

receiving a first encrypted portion of said encrypted video content of said data stream, wherein said first encrypted portion is defined by a first pre-determined period of time and spans for said first pre-determined period of time;

decrypting said first encrypted portion using said first encryption algorithm and said first key;

receiving data indicating a second encryption algorithm after said first pre-determined period of time;

receiving a second encrypted portion of said encrypted video content of said data stream, wherein said second encrypted portion is defined by a second pre-determined period of time and spans for said second pre-determined period of time;

decrypting said second encrypted portion using said second encryption algorithm and said first key;

receiving data indicating a second key;

receiving a third encrypted portion of said encrypted video content of said data stream, wherein said third encrypted portion is defined by a third pre-determined period of time and spans for said third pre-determined period of time;

decrypting said third encrypted portion using said second encryption algorithm and said second key.

8. The method of claim 7 wherein said first, second and third encrypted portions comprise respective first, second and third pluralities of encrypted transport packets, wherein a first parity of said first key is included in each of said first and second plurality of encrypted transport packets, and a second parity of said second key is included in each of said third plurality of encrypted transport packets.

9. The method of claim 7 wherein each of said first pre-determined period of tune and said second pre-determined period of time is ten seconds.

10. The method of claim 7 wherein said first and second encryption algorithms is each one of a Single Data Encryption Algorithm (SDEA), a Triple Data Encryption Algorithm (TDEA), a Common Scrambling Algorithm (CSA), or an Advanced Encryption Standard (AES) Algorithm.

11. The method of claim 7 wherein said data indicating said first encryption algorithm and said first key, said data indicating said second encryption algorithm and said data indicating said second key are received through a different channel than said first, second and third encrypted portions.

12. The method of claim 7 wherein said data indicating said first encryption algorithm and said first key is included in a first key packet.

13. An encryption device including both hardware and software for encrypting a data stream including a video content, said device comprising:

a data stream receiver for receiving said data stream;

a key generation module for generating first and second keys;

an encryption algorithm controller module comprising a first encryption algorithm, a second encryption algorithm and a third encryption algorithm;

wherein said encryption algorithm controller module is configured to;

encrypt a first portion of said encrypted video content of said data stream with said first encryption algorithm utilizing said first key to generate a first encrypted portion, wherein said first portion is defined by a first pre-determined period of time and spans for said first pre-determined period of time;

transmit said first encrypted portion to a storage device for storing said first encrypted portion;

change said first encryption algorithm to said second encryption algorithm after said first pre-determined period of time;

encrypt a second portion of said encrypted video content of said data stream with said second encryption algorithm utilizing said first key to generate a second encrypted portion, wherein said second portion is defined by a second pre-determined period of time and spans for said second pre-determined period of time;

transmit said second encrypted portion to said storage device for storing said second encrypted portion;

encrypt a third portion of said video content of said data stream with said third encryption algorithm utilizing said second key to generate a third encrypted portion, wherein said third portion is defined by a third pre-determined period of time and spans for said third pre-determined period of time;

transmit said third encrypted portion to said storage device for storing said third encrypted portion.

14. The device of claim 13 wherein each of said first pre-determined period of time and said second pre-determined period of time is ten seconds.

15. The device of claim 13 wherein said first and second encryption algorithms is each one of a Single Data Encryption Algorithm (SDEA), a Triple Data Encryption Algorithm (TDEA), a Common Scrambling Algorithm (CSA), or an Advanced Encryption Standard (AES) Algorithm.

16. The device of claim 13 wherein said encryption device is configured to generate data indicating said first encryption algorithm, said first key, said second encryption algorithm, said second key and said third encryption algorithm.

17. The device of claim 13 wherein said data indicating said first encryption algorithm and said first key is transmitted in a first key packet and said data indicating said second encryption algorithm and said second key is transmitted in a second key packet.