COMPRESSED DATA SCRAMBLED DISTRIBUTION DEVICE AND PLAYBACK DEVICE THEREOF

• US 20110081019A1
• Filed: 12/13/2010
• Published: 04/07/2011
• Est. Priority Date: 03/29/2005
• Status: Active Grant

• Current Assignee: KDDI Corporation
• Original Assignee: KDDI Corporation
• Inventors: Takishima, Yasuhiro, Takagi, Koichi, Sakazawa, Shigeyuki
• Granted Patent: US 8,181,027 B2
• Time in Patent Office: Days
• US Class Current: 380/268
• CPC Class Codes: G06T 1/0057 Compression invariant watermarking
• CPC Class Codes: G06T 2201/0053 Embedding of the watermark in the coding stream, possibly without decoding; Embedding of the watermark in the compressed domain
• CPC Class Codes: H04K 1/00 Secret communication
• CPC Class Codes: H04L 2209/608 Watermarking
• CPC Class Codes: H04L 9/3236 using cryptographic hash functions
• CPC Class Codes: H04N 21/2347 involving video stream encryption
• CPC Class Codes: H04N 21/4405 involving video stream decryption
• 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 7/165 Centralised control of user terminal subsequent to an upstream request signal H04N7/17345; Registering at central by two-way working H04N7/17309
• 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

The present invention provides a scrambled compressed data distribution device that can perform a high-resistance scrambled compressed data distribution by selectively using a plurality of types of scramble information and a playback device thereof.

A scrambling section scrambles compressed data by unique one of a plurality of scrambling methods. A hash value calculating section determines a hash value based on data b in a position where digital watermark data is not embedded, and an encrypting section encrypts the hash value with a secret key Sk(n) corresponding to the scrambling method and outputs an encrypted hash value c. A watermark data embedding section embeds the encrypted hash value in a watermark data embedding position of the data b and transmits the same as a compressed data stream d.

Claims

1. A distribution device comprising:

a predetermined plurality of different scrambling methods;

means for scrambling compressed data to produce scrambled compressed data by use of a selected one of the plurality of scrambling methods;

means for extracting data (D) in a position where digital watermark is embedded from the scrambled compressed data;

means for calculating a hash value based on a non-embedding position scrambled compressed data which do not include the data (D);

means for encrypting the hash value with a secret key assigned to the selected one of the plurality of scrambling methods; and

means for embedding the encrypted hash value at a watermark data embedding position in the scrambled compressed data.

5. A playback device comprising:

means for receiving the scrambled compressed data from the distribution device according to claim 1;

means for extracting the digital watermark from the received scrambled compressed data;

means for calculating a hash value based on a non-embedding position received scrambled compressed data which do not include the digital watermark;

means for decrypting the encrypted hash value by use of all public keys assigned to the plurality of scrambling methods;

means for determining a descrambling method by a coincident of the calculated hash value with the decrypted hash value; and

means for descrambling the received scrambled compressed data with the descrambling method.

6. The playback device according to claim 5, wherein the means for descrambling descrambles the received scrambled compressed data step by step.

2. A distribution device comprising:

a predetermined plurality of different scrambling methods;

means for scrambling compressed data to produce scrambled compressed data by use of a selected one of the plurality of scrambling methods on a first part of the compressed data and use of another selected one of the plurality of scrambling methods on a second part of the compressed data; and

means for embedding a digital watermark in the scrambled compressed data identifying the selected one and the selected another one of the plurality of scrambling methods used.

3. The distribution device according to claim 2, wherein each of the plurality of different scrambling methods is of a different strength.

4. A playback device comprising:

means for receiving the scrambled compressed data from the distribution device according to claim 2;

means for extracting the digital watermark from the received scrambled compressed data; and

means for determining descrambling methods corresponding to the selected one and the selected another one of the plurality of scrambling methods used based on the extracted digital watermark for the respective first and second parts of the compressed data and descrambling the received scrambled compressed data.