Copy protection method for digital media

• US 20020114458A1
• Filed: 02/04/2002
• Published: 08/22/2002
• Est. Priority Date: 02/05/2001
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Kuzmich, Vsevolod M., Belenko, Vyacheslav S.
• Granted Patent: US 7,506,376 B2
• Time in Patent Office: Days
• US Class Current: 380/201
• CPC Class Codes: H04N 21/23895 involving multiplex stream encryption
• CPC Class Codes: H04N 21/835 Generation of protective data, e.g. certificates protecting software against unauthorised usage in a vending or licensing environment G06F21/10
• CPC Class Codes: H04N 21/8352 involving content or source identification data, e.g. Unique Material Identifier [UMID]
• CPC Class Codes: H04N 21/8358 involving watermark protecting executable software by watermarking G06F21/16; image watermarking in general G06T1/0021; watermarks inserted in still images for transmission purposes H04N1/32144; inserting watermarks during video coding H04N19/467
• CPC Class Codes: H04N 7/1675 Providing digital key or authorisation information for generation or regeneration of the scrambling sequence pseudo-random number generators in general G06F7/58

Abstract

A method of digital media copy protection is disclosed. The method of the present invention is applicable to any type of digital media data and makes no assumptions on any specific media properties. The method includes a process of protecting digital media data with a public key using a hybrid cryptographic technique, a process of watermarking the media data, and an output device compliance testing process through an authenticated handshake protocol. Because of the media data protection with the hybrid cryptographic technique, a non-compliant playing device is not able to play or read a protected media data set. The output device compliance testing protocol is used to prevent the media signal from being copied to any non-compliant device. These features of the present invention are used to reduce the possibility of making any illegal copies on any nonstandard equipment. In addition, the data watermarking is used to modify the played and recorded media signals, to keep track of the identification information of the related devices for detecting any illegal copy maker, and to separate legal media data sets from the illegal data sets.

Claims

1. A copy protection method for digital media, the method comprising the steps of:

(a) encrypting an original media data set with a media key having a symmetric algorithm and encrypting said media key with each public key of compliant devices;

(b) delivering said encrypted media data set and said encrypted media key to a compliant playing device;

(c) decrypting said delivered media key with a private key of said playing device;

(d) decrypting said delivered media data set with said decrypted media key;

(e) adding a player watermark to said decrypted media data set if said decrypted data set is not marked with “

free copy”

, said player watermark containing a player identification of said playing device and player copy-control information;

(f) encrypting said watermark-added media data set with said decrypted media key and encrypting said decrypted media key with said each public key of compliant devices; and

(g) passing said media data set and media key encrypted in the step (f) to a compliant recording device.

2. The method of claim 1, wherein said each public key corresponds to an asymmetric algorithm.

3. The method of claim 1, wherein said original media data set includes an owner watermark containing an owner identification and owner copy-control information.

4. The method of claim 3, wherein said player copy-control information is derived from said owner copy-control information.

5. A copy protection method for digital media, the method comprising the steps of:

(a) encrypting an original media data set with a media key having a symmetric algorithm and encrypting said media key with each public key of compliant devices;

(b) delivering said encrypted media data set and said encrypted media key to a compliant playing device;

(c) decrypting said delivered media key with a private key of said playing device;

(d) decrypting said delivered media data set with said decrypted media key;

(e) adding a player watermark to said decrypted media data set if said decrypted data set is not marked with “

free copy”

, said player watermark containing a player identification of said playing device and player copy-control information.

(f) performing a compliance test through an authentication handshake process between said playing device and a displaying device; and

(g) transferring said watermark-added media data set to and displaying device only if said displaying device passes said test.

6. The method of claim 5, wherein said each public key corresponds to an asymmetric algorithm.

7. The method of claim 5, wherein said original media data set includes an owner watermark containing an owner identification and owner copy-control information.

8. The method of claim 7, wherein said player copy-control information is derived from said owner copy-control information.

9. The method of claim 5, wherein said player copy-control information is set to “

for display only”

.