Expiring encryption

• US 20060155652A1
• Filed: 06/16/2004
• Published: 07/13/2006
• Est. Priority Date: 06/16/2003
• Status: Abandoned Application

• Current Assignee: Steven M. Colby
• Original Assignee: Steven M. Colby
• Inventors: Colby, Steven M.
• Application Number:
  US10/869,736
• Publication Number:
  US 20060155652A1
• Time in Patent Office: Days
• US Class Current: 705/59
• CPC Class Codes: G06F 21/10 Protecting distributed programs or content, e.g. vending or licensing of copyrighted material protection in video systems or pay television H04N7/16 ; Digital rights management [DRM]
• CPC Class Codes: G06F 21/62 Protecting access to data via a platform, e.g. using keys or access control rules
• CPC Class Codes: G06F 2221/2137 Time limited access, e.g. to a computer or data

Abstract

Systems and methods of time dependent encryption are disclosed. The systems and methods are optionally used to facilitate decryption following expiration of a copyright term. An example is provided using the DeCSS decryption algorithm.

Claims

1. A digital media having data encoded thereupon, the data comprising:

encryption expiration data configured to be used to determine expiration of a copyright term, the encryption expiration data being stored in a read-only form; and

encrypted digital video data protected by copyright until expiration of the copyright term, the encrypted digital video data configured to be decrypted by a decryption system responsive to the expiration of the copyright term as determined using the encryption expiration data.

2. The digital media of claim 1, wherein the encryption expiration data includes a date of expiration of the copyright term.

3. The digital media of claim 1, wherein the encryption expiration data is encrypted.

4. The digital media of claim 1, wherein the encryption expiration data includes a plurality of copies of a date of expiration of the copyright term.

5. The digital media of claim 1, wherein the encryption expiration data includes a plurality of dates of expiration applicable to different subsets of the encrypted digital video data.

6. (canceled)

7. (canceled)

8. (canceled)

9. (canceled)

10. A secure clock comprising:

a power source;

a time piece configured to produce a time dependent output;

a static memory configured to store date data and to receive the time dependent output, the date data being advanced with a passage of time responsive to the time dependent output when power is available from the power source, and being stored in a non-volatile state when power is not available from the power source; and

an output configured to provide a date output responsive to the date data stored in the static memory.

11. The secure clock of claim 10, further including an encryption circuit configured to encrypt the date output.

14. The secure clock of claim 10, wherein the static memory is configured not to respond to received time dependent signals above a particular frequency.

15. The secure clock of claim 10, wherein the static memory includes a frequency dependent filter.

16. (canceled)

17. (canceled)

18. (canceled)

19. (canceled)

20. (canceled)

21. A digital media playback device comprising:

a secure clock configured to provide a date output, the date output representing a date that is either equal to or prior to a current date;

a media reader configured to read a digital media including encryption expiration data and encrypted digital video data, the encryption expiration data being representative of a copyright term expiration date associated with the encrypted digital video data;

a logic circuit configured to compare the date output with the encryption expiration data, and configured to decrypt the encrypted digital video data responsive to the comparison; and

a secure connection between the secure clock and the logic circuit.

22. The digital media playback device of claim 21, wherein the logic circuit includes computer instructions configured to decrypt data encrypted using a CSS Decryption Algorithm.

23. The digital media playback device of claim 21, wherein the logic circuit includes computer instructions configured to decrypt multiple layers of encryption.

24. The digital media playback device of claim 21, wherein the logic circuit includes computer instructions configured to decrypt a title key.

25. A method of decrypting data, the method comprising:

reading encrypted digital data;

reading encryption expiration data;

receiving date data from a secure clock;

comparing the encryption expiration data with the received date data;

determining whether encryption has expired responsive to the comparison; and

decrypting the encrypted digital data if the encryption has expired.

26. The method of claim 25, wherein the encrypted digital data is digital video data.

27. The method of claim 25, wherein the encrypted digital data and the encryption expiration data are stored on the same digital media.

28. The method of claim 25, wherein decrypting the encrypted digital data includes decrypting an encrypted title key.

29. A computer readable medium including computing instructions, the computing instructions comprising:

a code segment configured to determine if the encryption has expired, further decryption being responsive to the determination;

a code segment configured to decrypt a sector of a digital versatile disk encrypted with the encryption;

a code segment configured to decrypt a disk key using a player key; and

a code segment configured to decrypt a title key using the decrypted disk key.