Systems for fingerprinting digital data

• US 7,158,655 B2
• Filed: 12/22/2004
• Issued: 01/02/2007
• Est. Priority Date: 10/28/1999
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Yacobi, Yacov
• Primary Examiner(s): Mehta; Bhavesh M.
• Assistant Examiner(s): LAVIN, CHRISTOPHER L
• Application Number:
  US11/021,191
• Publication Number:
  US 20050111695A1
• Time in Patent Office: 741 Days
• Field of Search: None
• US Class Current: 382/100
• CPC Class Codes: G06T 1/005 Robust watermarking, e.g. average attack or collusion attack resistant
• CPC Class Codes: G06T 2201/0051 Embedding of the watermark in the spatial domain
• CPC Class Codes: G06T 2201/0061 Embedding of the watermark in each block of the image, e.g. segmented watermarking
• CPC Class Codes: G06T 2201/0063 in relation to collusion attacks, e.g. collusion attack resistant
• CPC Class Codes: H04N 1/32101 Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
• CPC Class Codes: H04N 2201/3235 Checking or certification of the authentication information, e.g. by comparison with data stored independently
• CPC Class Codes: H04N 2201/3236 Details of authentication information generation

Abstract

Systems for fingerprinting digital data are described. In one embodiment, a system for detecting a fingerprinting word is configured to receive a protected object that has embedded therein a fingerprinting word that contains a plurality of spread spectrum chips that are arranged in individual blocks that define individual spread sequences. The system processes the protected object sufficient to identify an entity that is associated with the fingerprinting word and which comprises a potential colluder. The system is configured to process the protected object by calculating a weight for each block and restricting the weights of certain blocks to a predetermined value.

Claims

1. A system for detecting a fingerprinting word comprising:

means for receiving a protected object that has embedded therein a fingerprinting word that contains a plurality of spread spectrum chips that are arranged in individual blocks that define individual spread sequences; and

means for processing the protected object sufficient to identify an entity that is associated with the fingerprinting word, said entity comprising a potential colluder, wherein said means for processing comprises;

means for calculating a weight for each block; and

means for restricting the weights of certain blocks to a predetermined value,

wherein said means for calculating comprises means for determining the weight of a block of an original spread sequence block value in accordance with the following equation;

Let x∈

{1, −

1} and y∈

{0, 1, −

1};

f(y, x)=1 if x is not equal to y and y is not equal to 0,

0 Otherwise.

Let X=(x₁, . . . , x_d), where x_i∈

{1, −

1} and Y=(y₁, . . ., y_d), where y_i∈

{1, −

1, 0}. The weight of Y relative to X is w(Y, X)—

which is the sum from i=1 to d of f(y_i, x_i), where “

d”

is the number of chips in each block.

2. A computer-readable medium having computer-executable instructions thereon which, when executed by a computer implement the system of claim 1.

3. A system for detecting a fingerprinting word comprising:

means for receiving a protected object that has embedded therein a fingerprinting word that contains a plurality of spread spectrum chips that are arranged in individual blocks that define individual spread sequences; and

means for processing the protected object sufficient to identify an entity that is associated with the fingerprinting word, said entity comprising a potential colluder, wherein said means for processing comprises;

means for calculating a weight for each block; and

means for restricting the weights of certain blocks to a predetermined value,

wherein said means for restricting comprises means for doing so if a block is likely unseen.

4. A computer-readable medium having computer-executable instructions thereon which, when executed by a computer implement the system of claim 3.

5. A system for detecting a fingerprinting word comprising:

means for receiving a protected object that has embedded therein a fingerprinting word that contains a plurality of spread spectrum chips that are arranged in individual blocks that define individual spread sequences; and

means for processing the protected object sufficient to identify an entity that is associated with the fingerprinting word, said entity comprising a potential colluder, wherein said means for processing comprises;

means for calculating a weight for each block; and

means for restricting the weights of certain blocks to a predetermined value,

wherein the predetermined value is equal to(1−

δ

)μ

, where;

For N users, and to defend against a collusion of size c, with error probability ε

, select the following;

Number of Γ

-symbols per a fingerprint word=L=2c ln(2N/ε

),

Block size (measured in chips)=d=8c² ln(8cL/ε

),

f=2 ln (4c² ln (2N/ε

)/ε

),

δ

=f/√

(d/2),

μ

=d/2.

6. A computer-readable medium having computer-executable instructions thereon which, when executed by a computer implement the system of claim 5.