Robust watermark

• US 9,319,752 B2
• Filed: 07/07/2014
• Issued: 04/19/2016
• Est. Priority Date: 06/08/2009
• Status: Active Grant

• Current Assignee: Synamedia Limited
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Mantin, Itsik, Kipnis, Aviad
• Primary Examiner(s): YANG, WEI WEN
• Application Number:
  US14/324,751
• Publication Number:
  US 20140355759A1
• Time in Patent Office: 652 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G06T 1/0021 Image watermarking
• CPC Class Codes: G06T 1/005 Robust watermarking, e.g. average attack or collusion attack resistant
• CPC Class Codes: G06T 2201/0061 Embedding of the watermark in each block of the image, e.g. segmented watermarking
• CPC Class Codes: H04N 21/23892 involving embedding information at multiplex stream level, e.g. embedding a watermark at packet level
• 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: H04N 21/8355 involving usage data, e.g. number of copies or viewings allowed
• 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 and system for embedding a watermark in block encrypted content, including encoding a bit string, the bit string including n bits, denoted b₀-b_n−1, the encoding including translating each bit, b₀-b_n−1, into a block of data, according to the following rule if b_i=1, then translate b_i into a block of data of a first type, and if b_i=0, then translate b_i into a block of data of a second type, thereby translating the n bits into n blocks of data corresponding to each bit b₀-b_n−1, arranging a composite block of data including the n blocks of data, and at least one additional block indicating the presence of the n blocks of data, and inserting the composite block of data into a content item as a watermark, wherein the watermarked content item is encrypted using an ECB mode of encryption. Related methods and apparatus are also described.

Claims

1. A method for embedding a watermark in block cipher encrypted content, the method comprising:

encoding a binary string comprising data for embedding as a watermark, the binary string comprising n bits, denoted b₀-b<sub>n−

1</sub>, where n>

2,the encoding comprising;

translating each bit, b₀-b<sub>n−

1</sub>, into a block of data, according to the following rule;

if b_i=1, then translate b_i into a block of data of a first type; and

if b_i=0, then translate b_i into a block of data of a second type, thereby translating the n bits into n blocks of data corresponding to each bit b₀-b<sub>n−

1</sub>;

arranging a composite block of data comprising;

the n blocks of data; and

at least one additional block indicating the presence of the n blocks of data; and

inserting the composite block of data into a content item as a watermark,

wherein the watermarked content item is block cipher encrypted using an ECB mode of encryption.

2. The method according to claim 1 wherein the composite block of data comprises:

at least one instance of the block of data of the first type; and

the n blocks of data.

3. The method according to claim 1 and further comprising prefixing a header to the composite block of data, the header comprising a plurality of a repeated block of data of a third type, thereby creating a prefixed composite block of data;

and

the inserting comprises inserting the prefixed composite block into the content item.

4. The method according to claim 1 and wherein the content comprises block cipher encrypted content.

5. The method according to claim 1 and wherein the content comprises at least one of:

video content;

audio content; and

a still image.

6. The method according to claim 1 and wherein the binary string comprises unique identification data.

7. The method according to claim 6 and wherein the unique identification data comprises a subscriber ID.

8. The method according to claim 6 and wherein the unique identification data comprises a smart card ID.

9. The method according to claim 3 and wherein the inserting comprises inserting the prefixed composite block of data between a first portion of the content item and a second portion of the content item.

10. The method according to claim 9 and wherein the inserting comprises inserting the watermark into a user data structure inserted between the first portion of the content item and the second portion of the content item.

11. The method according to claim 9 and wherein the inserting comprises inserting the watermark into a network abstraction layer structure of unspecified type inserted between the first portion of the content item and the second portion of the content item.

12. A method for detecting a watermark in watermarked content, the method comprising:

obtaining a block cipher encrypted content item, the encrypted content item being encrypted using an electronic codebook (ECB) mode of encryption, and comprising an encoded binary string comprising data for embedding as a watermark;

locating a prefix in the block cipher encrypted content item, the prefix comprising a repeated plurality of blocks of data of a first type;

locating, after the prefix, a composite block of data, the composite block of data comprising;

at least one instance of a block of data of a second type; and

a plurality of translated blocks of data;

translating the plurality of translated blocks of data into a binary string according to the following rule;

if a block to be translated comprises a block of data of the second type then translate the block of data into a bit b_i equal to 1; and

if the block to be translated comprises a block of data of a third type then translate the block of data into a bit b_i equal to 0;

arranging the binary string so that for i=0−

n−

1, the binary string is arranged as b₀-b<sub>n−

1</sub>, thereby determining the encoded binary string.