Digital watermarking to resolve multiple claims of ownership

Details Digital watermarking to resolve multiple claims of ownership Digital watermarking to resolve multiple claims of ownership

1997-08-27

2001-08-07

Swann, Tod (Department: 2132)

Electrical computers and digital processing systems: support

Multiple computer communication using cryptography

Particular communication authentication technique

C713S178000, C713S152000, C380S207000, C380S208000, C382S283000, C382S284000, C382S279000

Reexamination Certificate

active

06272634

ABSTRACT:

FIELD OF THE INVENTION
This invention relates generally to techniques for embedding data such as watermarks, signatures and captions in digital data, and more particularly to digital watermarking to resolve multiple claims of ownership.
BACKGROUND OF THE INVENTION
The world wide web, Internet, and many other distributed networks continue to provide opportunities for new and improved digital information dissemination. Digital audio, video, and images may be easily distributed, reproduced, and manipulated. However, these efficiencies also increase the problems associated with copyright enforcement. For this reason, creators and distributors of digital data are hesitant to provide access to their intellectual property. Reliable solutions to the problems associated with copyright protection of multimedia data are actively being pursued.
Digital watermarking has been proposed as a means to identify the owner or distributor of digital data. Watermarking is the process of encoding hidden copyright information in digital data by making small modifications to the data samples. Unlike encryption, watermarking does not restrict access to the data. Once encrypted data is decrypted, the media is no longer protected. A watermark is designed to permanently reside in the host data. When the ownership of a digital work is in question, the information can be extracted to characterize the owner.
A digital watermark is designed to be perceptually and statistically invisible with the host media (e.g., image, audio, or video). This ensures that the watermark does not degrade the host media. It also helps to prevent illegal removal of the copyright protection by a “pirate.” The watermark is also designed to be robust to signal distortions, incidental and intentional, applied to the host data. Possible distortions include normal signal processing operations, e.g., coding, filtering, scaling, etc., and deliberate attempts to forge, remove, or invalidate the watermark. Generally, a resourceful pirate may use a variety of signal processing operations to attack a digital watermarking. A pirate may attempt to defeat a watermarking procedure in three ways: (1) damage the host media to make the watermark undetectable, (2) establish that the watermarking scheme is unreliable, i.e., it detects a watermark when none is present.
Finally, (3) the extracted watermark must also correctly identify the owner and solve the deadlock issue when multiple parties claim ownership of a digital work. A deadlock may occur when a second party watermarks another person's data, thereby asserting unlawful ownership of another's intellectual property. That is, the main function of a watermarking algorithm is to unambiguously establish and protect ownership of data. However, many current watermarking schemes are unable to resolve rightful ownership of digital data when multiple ownership claims are made, i.e., when a deadlock problem arises. The inability to deal with deadlock is independent of how the watermark is inserted in the digital data or how robust it is to various types of modifications.
Watermarking techniques which do not require the original (non-watermarked) signal are the most vulnerable to ownership deadlocks. A pirate simply adds his or her watermark to the watermarked data. The data now has two watermarks. Prior art watermarking schemes are typically unable to establish who watermarked the data first.
Watermarking procedures that require the original data set for watermark detection also suffer from deadlocks. In such schemes, a party other than the owner may counterfeit a watermark by “subtracting off” a second watermark from the publicly available data and claim the result to be his or her original. This second watermark allows the pirate to claim copyright ownership since he or she can show that both the publicly available data and the original of the rightful owner contain a copy of their counterfeit watermark.
It would seem that the original (non-watermarked) media should be able to resolve the deadlock issue. Party A should have an original S
orig
which does not contain Party B's watermark. On the other hand, Party B's “original” must have Party A's watermark, since it is derived from the data Party A watermarked and distributed. However, current watermarking techniques are susceptible to an intelligent attack by Party B which destroys this logic. In particular, Party B can create a watermark W
B
which shows up in Party A's original S
orig
. Both originals, one from each party, contains the others watermark. Thus, a deadlock is created.
Party B's watermark is created by “subtracting off” a second watermark from the publicly available data. The difference is declared Party B's “original.” For example, suppose Party A watermarks data S
orig
A
using their watermark W
A
, and allows the watermarked data
S
water
A
=
S
orig
A
+
W
A
to be accessible to the public. Party B takes the watermarked data S
water
and creates their own “original” data S
water
B
by subtracting off a second watermark W
B
:
S
orig
B
=
S
water
A
-
W
B
.
Thus, both watermarks W
A
and W
B
exist in the publicly available data S
water
A
:
S
water
A
=
S
orig
A
+
W
A
=
S
orig
B
+
W
B
.
When S
water
A
is tested for W
A
and W
B
, both will be positively identified. The originals from each party may be consulted. Party A can find their watermark W
A
in Party B's original as
S
orig
B
-
S
orig
A
=
(
S
water
A
-
W
B
)
-
S
orig
A
=
(
S
orig
A
+
W
A
)
-
W
B
-
S
orig
A
=
W
A
-
W
B
.
However, Party B can find their watermark W
B
in Party A's original, as
S
orig
A
-
S
orig
B
=
S
orig
A
-
(
S
water
A
-
W
B
)
=
S
orig
A
-
(
S
orig
A
+
W
A
)
+
W
B
=
W
B
-
W
A
.
As a result, this second watermark allows the pirate to claim copyright ownership since he or she can show that both the publicly available data and the original of the rightful owner contain a copy of their counterfeit watermark. Thus, there is a need for watermarking procedures applicable to digital data that do not suffer from the described shortcomings, disadvantages and problems.
SUMMARY OF THE INVENTION
The above-identified shortcomings, disadvantages and problems found within the prior art are addressed by the present invention, which will be understood by reading and studying the following specification. The invention provides for the watermarking of digital data to resolve multiple claims of ownership.
In one embodiment of the invention, an author representation is based on the host digital data signal. An author is represented with a pseudo-random sequence (i.e., the watermark) created by a pseudo-random generator and two keys. One key is author dependent, while the second key is signal dependent. The representation is able to resolve rightful ownership in the face of multiple ownership claims.
In another embodiment of the invention, a watermarker uses two watermarks. A watermarking scheme uses the original signal to detect the presence of a watermark. This watermark is integrated with a second watermark that does not require the original signal. These embodiments of the invention solve the deadlock problem described in the background section of the application.
Further aspects, advantages and embodiments of the invention will become apparent by reference to the drawings, and by reading the following detailed description.


REFERENCES:
patent: 4313197 (1982-01-01), Maxemchuk
patent: 4425661 (1984-01-01), Moses et al.
patent: 4495620 (1985-01-01), Steele et al.
patent: 4969041 (1990-11-01), O'Grady et al.
patent: 5010405 (1991-04-01), Schreiber et al.
patent: 5060262 (1991-10-01), Bevins, Jr. et al.
patent: 5285498 (1994-02-01), Johnston
patent: 5315098 (1994-05-01), Tow
patent: 5319735 (1994-06-01), Preuss et al.
patent: 5325290 (1994-06-01), Cauffman et al.
patent: 5379345 (1995-01-01), Greenberg
patent: 5386240 (1995-01-01), Hori
patent: 5404377 (1995-04-01), Moses
patent: 5450490 (1995-09-01), Jensen et al.
patent: 5461426 (1995-10-01), Limberg et al.
patent: 5465269 (1995-11-01), Schaffner et al.
patent: 5465308 (1995-11

Affiliated with

Also associated with

Rating

Digital watermarking to resolve multiple claims of ownership does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Digital watermarking to resolve multiple claims of ownership, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Digital watermarking to resolve multiple claims of ownership will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2491719