Recoverable digital content degradation: method and apparatus

• US 6,963,884 B1
• Filed: 03/10/2000
• Issued: 11/08/2005
• Est. Priority Date: 03/10/1999
• Status: Expired due to Fees

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Levy, Kenneth L.
• Primary Examiner(s): Coby, Frantz
• Application Number:
  US09/522,678
• Time in Patent Office: 2,069 Days
• Field of Search: 705/1, 379/93.31, 379/93, 379/399.01, 395/182.03, 707/202, 707/200, 707/203, 380/19, 380/15, 380/203, 380/37, 360/137, 369/47, 364/569, 331/1.A, 382/232, 382/115
• US Class Current: 1/1
• CPC Class Codes: G11B 20/00086 Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: H04N 21/23406 involving management of server-side video buffer
• CPC Class Codes: H04N 21/23476 by partially encrypting, e.g. encrypting the ending portion of a movie
• CPC Class Codes: H04N 21/64715 Protecting content from unauthorized alteration within the network verifying the information received for network security in communication control or processing H04L63/12; integrity in wireless network security H04W12/10
• CPC Class Codes: Y10S 707/99953 Recoverability

Abstract

In many situations, it is desirable to restrict access to digital content. This invention presents an extremely efficient and simple method and apparatus to degrade and recover digital content. The invented process is based upon searching the data for detection criteria and then adjusting neighboring point(s) to degrade the content, or re-adjusting the neighboring point(s) to recover the original content. For example, one could search for threshold crossings, and scale the following point by a number between 0 and 1 for degradation, or re-scale the following point by the inverse scaling value to recover the original data. The apparatus includes a logic processor and storage unit to implement the degradation and recovery process.

Claims

1. A process to intentionally degrade original digital data comprising:

searching the original digital data for detection criteria; and

after locating detection criteria, adjusting at least one neighboring point associated with the detection criteria, wherein the original digital data is degraded in quality by said adjusting, but the original digital data is recoverable from the intentionally degraded digital data.

2. The process of claim 1 in which the detection criteria comprises a pseudo-random sequence.

3. The process of claim 1 in which the adjustment of the at least one neighboring point involves a pseudo-random sequence.

4. The process in claim 1 in which the detection criteria includes a threshold crossing.

5. An apparatus comprising:

a logic processor; and

a storage unit comprising means for analyzing digital content, wherein the digital content has been transformed with a self-synchronizing degradation from an original state of the digital content, and means for recovering the original state of the digital content from the self-synchronized degraded digital content.

19. The method of claim 5, wherein said means for recovering the original state of the digital content comprises means for analyzing the degraded digital content to identify a plurality of detection criteria, and means for adjusting for each of the detection criteria the degraded digital content according to a predetermined process.

20. The method of claim 19, wherein the predetermined process corresponds with a process used to degrade the digital content from the original state.

21. The method of claim 20, and wherein said adjusting means helps to restore the degraded digital content to the original state.

22. The method of claim 19, wherein for each of the plurality of detection criteria there exists in the degraded digital content a group of neighboring points, wherein said adjusting means adjusts, for each group, each member of the group of neighboring points.

23. The method of claim 5 wherein the self-synchronizing degradation comprises intentional degradation.

6. A method of restoring degraded digital content, wherein the degraded digital content comprises degradation from an original state of the digital content, said method comprising:

analyzing the degraded digital content to identify a plurality of detection criteria, wherein for each of the plurality of detection criteria there exists in the degraded digital content a group of neighboring points; and

for each group of neighboring points, adjusting each member of a group of neighboring points according to a predetermined process, wherein the predetermined process corresponds with a process used to degrade the digital content from the original state, and wherein said adjusting helps to restore the degraded digital content to the original state.

7. The method of claim 6, wherein the group comprises at least one neighboring point.

8. The method of claim 6, wherein the plurality of detection criteria comprises a pseudo-random sequence.

9. The method of claim 6, wherein the plurality of detection criteria includes a threshold crossing.

10. The method of claim 6, wherein the predetermined process is an inverse of the process used to degrade the digital content from the original state.

11. The method of claim 6, wherein the digital content comprises audio content.

12. The method of claim 6, wherein the digital content comprises video content.

13. The method of claim 6, wherein the digital content comprises image content.

14. The method of claim 6, wherein the degraded digital content is intentionally degraded in a manner which does not convey information.

15. A method of restoring intentionally degraded digital content, wherein the intentionally degraded digital content comprises intentional degradation from an original state of the digital content, said method comprising:

analyzing the intentionally degraded digital content to identify a plurality of detection criteria; and

for each of the plurality of detection criteria, adjusting the intentionally degraded digital content according to a predetermined process, wherein the predetermined process corresponds with a process used to intentionally degrade the digital content from the original state, and wherein said adjusting restores the intentionally degraded digital content to the original state.

16. The method of claim 15, wherein for each of the plurality of detection criteria there exists in the degraded digital content a group of neighboring points, wherein said adjusting comprises for each group adjusting each member of the group of neighboring points.

17. The method of claim 15, wherein the digital content comprises audio.

18. The method of claim 15, wherein the digital content comprises video.

24. An audio player for playing back an audio signal distributed through a network, which comprises:

removing means for removing degradation data from an audio signal embedded with data using a specific key, said degradation data being at a signal level which is audible to the human sense of hearing; and

playback means for playing back an audio signal.

25. The player of claim 24 wherein the degradation data includes embedded data.

26. An audio distribution system including a distribution apparatus for distributing an audio signal through a network and an audio player for playing back said distributed audio signal, wherein said distribution apparatus comprises embedding means for embedding in said audio signal degradation data of which a signal level is audible to the human sense of hearing when the audio signal is played back;

and wherein said audio player comprises removing means for removing degradation data from said embedded audio signal using a specific key.

27. An audio distribution method wherein a sending side processes an audio signal for distribution through a network and a receiving side plays back the audio signal, said method comprises:

embedding degradation data in an audio signal at the sending side, the degradation data having a signal level that is audible to the human sense of hearing when the audio signal is played back; and

removing degradation data from the embedded audio signal using a specific key at playback.