Motion picture file encryption method and digital rights management method using the same

• US 20050123136A1
• Filed: 12/08/2004
• Published: 06/09/2005
• Est. Priority Date: 12/08/2003
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd., Sejong Industry-Academy Cooperation Foundation
• Original Assignee: Daeyang Foundation, Samsung Electronics Co. Ltd.
• Inventors: Kim, Jun-il, Shin, Dong-kyoo, Shin, Dong-il, Kim, Yong-bin, Choi, Soon-yong
• Granted Patent: US 8,755,524 B2
• Time in Patent Office: Days
• US Class Current: 380/217
• 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 20/00224 wherein the key is obtained from a remote server
• CPC Class Codes: G11B 20/00492 wherein content or user data is encrypted
• CPC Class Codes: G11B 20/005 wherein only some specific parts of the content are encrypted, e.g. encryption limited to I-frames
• CPC Class Codes: G11B 20/00731 involving a digital rights management system for enforcing a usage restriction
• CPC Class Codes: H04L 2209/603 Digital right managament [DRM]
• CPC Class Codes: H04L 9/083 involving central third party, e.g. key distribution center [KDC] or trusted third party [TTP]
• CPC Class Codes: H04L 9/321 involving a third party or a trusted authority
• CPC Class Codes: H04N 2005/91364 the video signal being scrambled
• CPC Class Codes: H04N 21/234318 by decomposing into objects, e.g. MPEG-4 objects
• CPC Class Codes: H04N 21/2347 involving video stream encryption
• CPC Class Codes: H04N 21/2541 Rights Management protecting software against unauthorised usage in a vending or licensing environment G06F21/10; security in data switching network management H04L41/28; security management or policies for network security H04L63/20; access security in wireless networks H04W12/08
• CPC Class Codes: H04N 21/4627 Rights management associated to the content security in data switching network management H04L41/28; security management or policies for network security H04L63/20; access security in wireless networks H04W12/08
• 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 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 encrypting a motion picture file and a method of digital rights management using the same, wherein encryption method includes: extracting information on the location of at least one video sample, which is a real-time streaming unit, from meta-data of the motion picture file; extracting the video samples based on the location information; encrypting the extracted video samples, excluding a start code within a video sample header of each extracted video sample, based on predetermined encryption information; and producing an encrypted motion picture file by recombining the encrypted video samples. Since the file is encrypted in units of video object planes (VOPs) while maintaining an MEPG-4 file format, the encryption method can be easily applied to a completed file format and streaming service is also possible.

Claims

1. A method of encrypting a motion picture file comprising a plurality of video samples, the method comprising:

extracting location information of at least one video sample;

extracting video samples based on the location information which has been extracted;

encrypting a portion of extracted video samples, excluding video sample identifying information that identifies the extracted video samples, according to encryption information; and

generating an encrypted motion picture file by re-inserting encrypted video samples into the motion picture file.

2. The method of claim 1, wherein the encryption information includes an encryption key and an encryption type.

3. The method of claim 2, wherein the encryption key is transmitted using a digital rights management service.

4. The method of claim 2, wherein encryption is performed such that a message word before encryption has a same number of bits as a corresponding codeword after encryption.

5. The method of claim 4, wherein the encryption method is one of a data encryption standard (DES) and a standard Korean encryption algorithm (SEED).

6. The method of claim 1, wherein the motion picture file is an MPEG file.

7. The method of claim 1, wherein the motion picture file is an MPEG file, and each of the video samples is a video object plane (VOP) which shows streaming units and which is included in a chunk.

8. The method of claim 7, wherein the extracting the location information of the at least one video sample comprises:

extracting a chunk size, a chunk offset, and a sample size from meta-data within a sample table atom among lower level atoms within a moov atom where meta-data of VOPs is saved; and

calculating location information of each VOP based on the chunk size, the chunk offset, and the sample size.

9. The method of claim 8, wherein the encryption information further comprises an encryption mode which is one of a first mode which encrypts only I-VOPs among the VOPs, a second mode which encrypts only B-VOPs and P-VOPs among the VOPs, and a third mode which encrypts all of the VOPs.

10. The method of claim 9, wherein the encryption information further comprises a VOP ID to identify a VOP that is to be encrypted.

11. The method of claim 10, wherein the moov atom comprises a digital rights management atom, and the digital rights management atom comprises the encryption information as meta-data.

12. The method of claim 11, wherein the digital rights management atom is saved as a top lower level atom of the moov atom.

13. The method of claim 11, wherein the digital rights management atom comprises an encryption flag and an entry table, and the encrypting comprising encrypting all VOPs when the encryption flag is set as a first type and encrypting only VOPs that are relevant to VOP ID included within the entry table when the encryption flag is set as a second type.

14. A method of decrypting a motion picture file that is selectively encrypted in units of video samples based on encryption information, the decryption method comprising:

checking video sample identifying information that identifies a start of each of the video samples in the motion picture file;

extracting each of the video samples based on the video sample identifying information;

extracting encrypted video samples among the video samples which have been extracted based on the encryption information, wherein only portion of the encrypted video samples, excluding the video sample identifying information, is encrypted;

decrypting the encrypted video samples based on decryption information corresponding to the encryption information; and

generating a decrypted motion picture file by re-inserting the decrypted video samples in the motion picture file.

15. The method of claim 14, wherein the encryption information comprises an encryption key and an encryption type.

16. The method of claim 14, wherein the decryption information is transmitted using a digital rights management service.

17. The method of claim 15, wherein encryption is performed such that a message word before encryption has the same number of bits as a corresponding codeword after encryption.

18. The method of claim 17, wherein an encryption method is one of a data encryption standard (DES) and a standard Korean encryption algorithm (SEED).

19. The method of claim 15, wherein the motion picture file is an MPEG file, each of the video samples is a video object plane (VOP), and the encryption information further comprises an encryption mode which is one of a first mode which encrypts only I-VOPs among the VOPs, a second mode which encrypts only B-VOPs and P-VOPs among the VOPs, and a third mode which encrypts all of the VOPs.

20. The method of claim 15, wherein the encryption information further comprises a VOP ID to identify a VOP that is to be encrypted.

21. A method of a digital rights management (DRM) using a contents server and a contents client, the method comprising:

performing a user authentication process for a predetermined motion picture file wherein the contents server and the contents client receive encryption and decryption information, respectively;

encrypting, at the contents server, the motion picture file in units of video samples based on the encryption information;

transmitting the motion picture file which has been encrypted from the contents server to the contents client through a streaming server;

extracting encrypted video samples from the motion picture file at the contents client;

decrypting only a portion of the encrypted video samples, excluding the video sample identifying information which identifies the video samples, using the decryption information at the contents client; and

reproducing a decrypted motion picture file in real-time by re-inserting the decrypted video samples in the motion picture file at the contents client.

22. The method of claim 21, wherein receiving the encryption and decryption information comprises:

transmitting a user authentication request regarding the motion picture file from the contents client to a DRM server;

performing a user authentication process at the DRM server and transmitting DRM authentication information which includes information on user authentication from the DRM server to the contents server;

generating at the contents server an encryption key based on the DRM authentication information and the encryption information based on the encryption key and optional encryption information input by the user; and

transmitting the encryption information from the contents server to the DRM server, wherein the DRM server transmits the decryption information that corresponds to the encryption information to the contents client.

23. The method of claim 22, wherein the motion picture file is an MPEG file.

24. The method of claim 22, wherein the motion picture file is an MPEG file, and the video samples are video object planes (VOPs) which are streaming units and are included in a chunk, and the encrypting the motion picture file in units of video samples comprises:

generating information regarding a location of each VOP by parsing a moov atom of the MPEG file;

extracting each VOP within a media data atom of the MPEG file based on the information regarding the location of each VOP;

encrypting a portion of each of the extracted VOPs, excluding a start code within a VOP header, based on the encryption information; and

generating an encrypted MPEG file by re-inserting the VOPs which have been encrypted in the MPEG file.

25. The method of claim 24, wherein the generating information regarding the location of each VOP comprises:

extracting a chunk size, a chunk offset, and a sample size from a sample table atom among lower level atoms within a moov atom; and

calculating the information regarding the location of each VOP based on the chunk size, the chunk offset, and the sample size.

26. The method of claim 21, wherein the encryption information includes an encryption key and an encryption type.

27. The method of claim 26, wherein the encrypting is performed such that a message word before encryption has the same number of bits as a corresponding codeword after encryption.

28. The method of claim 27, wherein an encryption method is one of a data encryption standard (DES) and a standard Korean encryption algorithm (SEED).

29. The method of claim 21, wherein the video samples are video object planes (VOPS) which are streaming units and are included in a chunk, and extracting the encrypted video samples comprises:

extracting only a data portion of a packet by decapsulating a transmission protocol header of the transmitted packet;

producing a combined data stream by recombining the data portion of the packet;

checking VOP identifying information that identifies each VOP within the combined data stream;

extracting each VOP based on the VOP identifying information; and

extracting encrypted VOPs among the extracted VOPs based on the encryption information.