Enforcing software independent content protection in an electronic device
View Patent ↗A Set Top Box (STB) or client computer includes a communication interface operable to receive digital messages and digital content, memory operable, and processing circuitry coupled to the communication interface and to the memory. The STB is operable to receive a digital message, extract a key portion from the digital message, decrypt the key portion, descramble the digital content using the decrypted key portion, extract a rights portion from the digital message, decrypt the rights portion, determine protected and unprotected digital content based upon the rights portion, write the unprotected digital content to an unprotected portion of the memory, and write the protected digital content to a protected portion of the memory. The decrypted key portion may include a plurality of Program IDs (PIDs) and the decrypted rights portion may include protection data for each PID. A security processor may prevent a central processing unit from accessing the protected portion of the memory.
1. An apparatus comprising:
a communication interface operable to receive digital messages and digital content;
memory operable to store the digital messages and the digital content; and
processing circuitry coupled to the communication interface and to the memory and operable to:
receive a digital message and the digital content;
extract a key portion and a rights portion from the digital message;
decrypt the key portion using a program key to produce a program identification key (PID);
descramble the digital content;
decrypt the rights portion using the PID;
determine protected and unprotected digital content based upon the rights portion;
write the unprotected digital content to an unprotected portion of the memory; and
write the protected digital content to a protected portion of the memory.
2. The apparatus of claim 1 , wherein:
the decrypted key portion comprises a plurality of content identifiers; and
the decrypted rights portion comprises protection data for each of the content identifiers.
3. The apparatus of claim 1 , wherein the processing circuitry comprises:
a central processing unit; and
at least one audio/video processor, wherein the protected portion of the memory is not accessible by the central processing unit and is accessible by the at least one audio/video processor.
4. The apparatus of claim 1 , wherein the apparatus comprises at least one of:
a cable set top box receiver;
a satellite set top box receiver;
a Digital Subscriber Line (DSL) set top box receiver;
a Wireless Wide Area Network (WWAN) receiver;
a client computer;
a tablet computing device; and
a phone.
5. The apparatus of claim 1 , wherein in extracting the rights portion from the digital message the processing circuitry is operable to:
decrypt the key portion to produce a decrypted result; and
decrypt the rights portion using the decrypted result to produce the decrypted rights portion.
6. The apparatus of claim 5 , wherein:
the decrypted key portion comprises a plurality of content identifiers; and
the decrypted rights portion comprises protection data for each of the content identifiers.
7. The apparatus of claim 1 , wherein the processing circuitry is operable to scramble the protected digital content before it is written to the protected portion of the memory.
8. The apparatus of claim 1 , wherein:
the rights portion further comprises a validation portion; and
the processing circuitry is operable to validate the validation portion.
9. The apparatus of claim 1 , wherein the key portion and the rights portion are tied together cryptographically.
10. A method comprising:
receiving content and a digital message by an electronic device from a remote device;
extracting a key portion and a rights portion from the digital message;
decrypting the key portion using a program key to produce a program identification key (PID);
decrypting the rights portion using the PID;
receiving digital content from a remote device;
descrambling the digital content using the decrypted key portion;
determining protected and unprotected digital content based upon the rights portion;
writing the unprotected digital content to an unprotected portion of memory; and
writing the protected digital content to a protected portion of the memory wherein the protected portion may only be accessed by a content processor configured to access the protected portion.
11. The method of claim 10 , wherein:
the decrypted key portion comprises a plurality of content identifiers; and
the decrypted rights portion comprises protection data for each of the content identifiers.
12. The method of claim 10 , wherein extracting the rights portion from the digital message comprises:
decrypting the key portion to produce a decrypted result; and
decrypting the rights portion using the decrypted result to produce the decrypted rights portion.
13. The method of claim 10 , further comprising scrambling the protected digital content before it is written to the protected portion of the memory.
14. The method of claim 10 , further comprising validating the rights portion.
15. The method of claim 10 , further comprising precluding access to the protected portion of the memory by a central processing unit.
16. The method of claim 10 , further comprising allowing access to the protected portion of the memory by at least one audio/video processing unit.
17. The method of claim 10 , wherein the key portion and the rights portion are tied together crypto graphically.
18. An apparatus comprising:
a communication interface operable to receive digital messages and digital content;
memory operable to store the digital messages and the digital content; and
processing circuitry coupled to the communication interface and to the memory and including a central processing unit and at least one audio/video processor, the processing circuitry operable to:
receive a digital message and the digital content;
extract a key portion and a rights portion from the digital message;
decrypt the key portion using a program key to produce a program identification key (PID);
descramble the digital content using the decrypted key portion;
decrypt the rights portion using the PID;
determine protected and unprotected digital content based upon the rights portion;
write the unprotected digital content to an unprotected portion of the memory that is accessible to both the central processing unit the at least one audio/video processor; and
write the protected digital content to a protected portion of the memory that is accessible only to the at least one audio/video processor and is not accessible by the central processing unit.
19. The apparatus of claim 18 , wherein:
the decrypted key portion comprises a plurality of content identifiers; and
the decrypted rights portion comprises protection data for each of the content identifiers.
20. The apparatus of claim 18 , wherein the apparatus comprises at least one of:
a cable set top box receiver;
a satellite set top box receiver;
a Digital Subscriber Line (DSL) set top box receiver;
a Wireless Wide Area Network (WWAN) receiver;
a client computer;
a tablet computing device; and
a phone.
21. The apparatus of claim 18 , wherein in extracting the rights portion from the digital message the processing circuitry is operable to:
decrypt the key portion to produce a decrypted result; and
decrypt the rights portion using the decrypted result to produce the decrypted rights portion.
22. The apparatus of claim 18 , wherein the processing circuitry is operable to scramble the protected digital content before it is written to the protected portion of the memory.
23. The apparatus of claim 18 , wherein the key portion and the rights portion are tied together cryptographically.