Deterring theft of media recording devices by encrypting recorded media files

• US 20030226023A1
• Filed: 06/03/2002
• Published: 12/04/2003
• Est. Priority Date: 06/03/2002
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Peters, Mark E.
• Granted Patent: US 7,418,599 B2
• Time in Patent Office: Days
• US Class Current: 713/193
• 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: G11B 20/0021 involving encryption or decryption of contents recorded on or reproduced from a record carrier
• CPC Class Codes: G11B 20/00231 wherein the key is obtained from a local external medium, e.g. a card
• CPC Class Codes: G11B 20/00826 wherein a spoiler signal is added to degrade the signal quality

Abstract

Techniques are disclosed for deterring theft of media recording devices. Input received from a sensor, or some portion of the input, is encrypted prior to storing a media file. A decryption key must be provided when the media file is to be played back. If the key is not provided, then the file is preferably still played back, but is played back in a degraded manner. For example, a background color or other filler may be rendered in place of the encrypted portion. Additional parts of the file may also be degraded during playback. By making the playback unpleasant for the listener/viewer, theft of the recording device will be much less desirable—yet recording can continue uninterrupted, thereby minimizing disruption to legitimate users. The disclosed techniques may also be used to deter theft of the recorded media.

Claims

1. A method of encrypting media files to deter theft, comprising steps of:

capturing input with a media recording device;

encrypting at least a portion of the captured input; and

recording the captured input, as encrypted by the encrypting step, wherein the encryption causes playback of the recording to be degraded unless the encryption can successfully decrypted.

2. The method according to claim 1, wherein the encrypting step further comprises using shared key cryptography.

3. The method according to claim 1, wherein the encrypting step further comprises using public key cryptography.

4. The method according to claim 1, wherein the encrypting step further comprises using shared key cryptography to encrypt the portion of the captured input and using public key cryptography to encrypt a symmetric key value used for the shared key cryptography.

5. The method according to claim 1, wherein the encrypting step is performed prior to the recording step.

6. The method according to claim 1, wherein the encrypting step is performed in conjunction with the recording step.

7. The method according to claim 1, wherein the encrypting step is performed while compressing the captured input for storage by the recording step.

8. The method according to claim 1, further comprising the step of playing back the recording, further comprising the steps of:

decrypting the recorded input;

playing back the captured input if the decrypting step is successful; and

playing back a distorted version of the captured input otherwise.

9. The method according to claim 8, wherein the distorted version comprises the captured input with some portion thereof overlaid by a garbled pattern.

10. The method according to claim 8, wherein the captured input is an image stream and wherein the distorted version comprises the captured image stream with a filler pattern displayed in some portion thereof.

11. The method according to claim 10, wherein the portion in which the filler pattern is displayed corresponds to the encrypted portion which was not successfully decrypted.

12. The method according to claim 1, wherein the captured input is an image stream and wherein the encrypting step encrypts the image stream prior to the recording step.

13. The method according to claim 1, wherein the encrypting step also encrypts at least a portion of a thumbnail version of the captured input.

14. The method according to claim 8, wherein the captured input is an audio stream and wherein the distorted version comprises the captured audio stream with a white noise stream played for the portion which was not successfully decrypted.

15. The method according to claim 1, wherein the encrypting step uses a public key to encrypt a shared key and uses the shared key to encrypt the portion of the captured input, and further comprising the step of subsequently playing back the recording, wherein the subsequently playing back step further comprises the steps of:

determining if a private key corresponding to the public key is available;

decrypting the recording if the private key is available, and playing back a result of the decryption; and

if the private key is not available, playing back that portion of the captured input which was not encrypted and playing back substitute information in place of the captured input that was encrypted.

16. The method according to claim 15, wherein the decrypting step further comprises the steps of:

using the private key to decrypt the encrypted shared key; and

using the decrypted shared key to decrypt the encrypted portion of the captured input, thereby creating the result of the decryption; and

wherein the step of playing back substitute information further comprises the step of rendering a filler pattern in place of the encrypted portion.

17. The method according to claim 16, further comprising the steps of:

compressing the captured input, as encrypted by the encrypting step, prior to the recording step; and

decompressing the recording when creating the result of the decryption.

18. The method according to claim 15, wherein the private key is stored in a key fob which, when operably connected to a device with which the subsequent playing back step is to be performed, makes the private key available.

19. The method according to claim 15, wherein the public key is obtained from a digital certificate and the private key is associated with the public key.

20. The method according to claim 19, wherein the public key belongs to the playback device.

21. The method according to claim 19, wherein the public key belongs to a person performing the subsequent playing back step on the playback device.

22. The method according to claim 15, wherein the private key is stored on a smart card and is made available to a device on which the subsequently playing back step is to be performed by operably connecting the smart card with a smart card reader.

23. The method according to claim 22, wherein the decrypting step is performed by the smart card.

24. The method according to claim 15, wherein the private key is stored in a cable and is made available to a device on which the subsequently playing back step is to be performed by operably connecting the cable to the device.

25. The method according to claim 15, wherein a device on which the subsequently playing back step is to be performed is also used for the capturing, encrypting, and recording steps.

26. The method according to claim 15, wherein the private key is made available to the subsequently playing back step for a limited time, after which the private key must be re-supplied in order to be available.

27. The method according to claim 15, wherein the private key is made available from a program used to perform the subsequently playing back step.

28. A system for deterring theft of media recording devices, comprising:

means for capturing input with a media recording device;

means for encrypting a portion of the captured input; and

means for recording the captured input, including the portion encrypted by the means for encrypting, such that playback of the recording will be degraded unless the encryption can successfully decrypted.

29. The system according to claim 28, further comprising:

means for decrypting the recorded input;

means for playing back the captured input if the means for decrypting is successful; and

means for playing back a degraded version of the captured input otherwise.

30. Program instructions for deterring theft of media recording devices, the program instructions embodied on one or more media and comprising:

program code means for capturing input with a media recording device;

program code means for encrypting a portion of the captured input; and

program code means for recording the captured input, including the portion encrypted by the program code means for encrypting, such that playback of the recording will be degraded unless the encryption can successfully decrypted.

31. The program instructions according to claim 30, wherein the program code means for encrypting uses a public key to encrypt a shared key and uses the shared key to encrypt the portion of the captured input, and further comprising program code means for playing back the recording, wherein the program code means for playing back further comprises:

program code means for determining if a private key corresponding to the public key is available;

program code means for decrypting the recording if the private key is available, and playing back a result of the decryption; and

if the private key is not available, program code means for playing back that portion of the captured input which was not encrypted and playing back substitute information in place of the captured input that was encrypted.