Patent EP0905967A1 successfully refreshed from Google Patents.
EP0905967A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method for generating digital watermarks and for exchanging data containing digital watermarks
Assignee: Digital Copyright Technologies AG
•
Filing: 1997-09-26
•
Granted: —
•
Expires: 2017-09-26
Abstract
Abstract A method for generating digital watermarks and for exchanging data containing such watermarks is described. The system is based on an watermarking technique which is robust against image transformation techniques such as compression, rotation, translation, and scaling. It uses modulation of the magnitude components in Fourier space and adds/reads a template in the log polar transform of the magnitude components. The template is used for analyzing scaling and rotation. In addition, the system applies cryptographic protocols and public key techniques for both, encoding the watermark and transferring watermarked data. Preferably, an author (ICH) encodes the watermark using an asymmetric cryptographic key pair provided by a public key infrastructure (PKI) and registers the watermarked data at a trusted registration party (ICO) before transmitting the data to a receiving party (IB). The latter can use the public key infrastructure (PKI) for verifying authorship. Transmission between the parties uses data protection provided by the cryptographic keys.
Inventors
- 👤 Alexander Herrigel
- 👤 Joseph J.K. Oruanaidh
- 👤 Thierry Pun
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 13:30
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/32; H04N1/32101; H04N1/32144; H04N1/32149; H04N1/32154; G; G06; G06T; G06T1/00; G06T1/0021; G06T1/005; G06T1/0064; H04L; H04L63/00; H04L63/04; H04L63/0428; H04L63/0442; H04L63/045; H04L9/00; H04L9/32; H04L9/3247; H04N1/3216; H04N1/32187; H04N1/32192; H04N1/32267; H04N1/32309; H04N21/00; H04N21/80; H04N21/83; H04N21/835; H04N21/8358; G06T2201/00; G06T2201/005; G06T2201/0052; G06T2201/0083; H04L2209/00; H04L2209/34; H04L2209/60; H04L2209/608; H04L2463/00; H04L2463/103; H04N2201/00; H04N2201/32; H04N2201/3201; H04N2201/3225; H04N2201/3233; H04N2201/3269; H04N2201/327; H04N2201/3278
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
153 words
A method for generating and transmitting a
data set between two parties H and B comprising the steps
of a) providing a cover data set (CI) corresponding
to the data set to be transmitted, b) generating a stego data set (SI) of said
cover data set (CI) by embedding at least one digital watermark
in said cover data set (CI), wherein said watermark
is encoded using at least one key of an asymmetric
cryptographic key pair (ps H , vs H ) of H, said key pair
comprising a secret private key (ps H ) and a known public
key (vs H ) derived therefrom, c) establishing a cryptographically secure
transmission between parties H and B with a key protocol
using at least said key pair (ps H , vs H ) of H, d) transmitting said stego data set (SI) from
said party H to said party B within said secure transmission.
Claim 2
Dependent Claim
78 words
The method of claim 1, wherein said cryptographically
secure transmission between said parties H
and B is established using an asymmetric key protocol
(AKAP(H,B,K HB ,ps H ,vs H ,ps B ,vs B )) based on said key pair
(ps H , vs H ) of H and a private and public asymmetric cryptographic
key pair (ps B , vs B ) of B for generating a common
key (K HB ) between said parties H and B.
Claim 3
Independent Claim
26 words
The method of one of the preceding claims
wherein said key pair (ps H , vs H ) of H is an elliptic
curve key pair.
Claim 4
Independent Claim
62 words
The method of one of the preceding claims
wherein said step b) further comprises the steps of generating at least one private watermark,
wherein said private watermark is encoded using said private
key (ps H ) of H, and preferably also generating at least one public watermark,
wherein said public watermark is encoded using said public
key (vs H ) of H.
Claim 5
Dependent Claim
37 words
The method of claim 4 wherein said private
watermark is encoded using a hash value (crh(ps H )) of
said private key (ps H ) and can be decoded by using said
hash value (crh(ps H )).
Claim 6
Independent Claim
44 words
The method of one of the preceding claims
wherein said step b) comprises the step of generating at
least one public watermark, wherein said public watermark
is encoded using a hash value (crh(vs H )) of said public
key (vs H ) of H.
Claim 7
Independent Claim
92 words
The method of one of the preceding claims
wherein said step b) comprises the steps of i) providing a message (s 1 , s 2 , ..., s M ) to
be transmitted in said at least one watermark, said message
consisting of a plurality of symbols, ii) providing a pseudo random generator
seeded with a seed value derived from at least one key of
said key pair (ps H , vs H ) of H or a hash value thereof, iii) encoding said message using values from
said pseudo random generator.
Claim 8
Independent Claim
66 words
The method of claims 7 wherein said step
iii) comprises for each of said symbols (s i ), calculating a
symbol vector ( r i ), wherein all elements of said vector
are derived from numbers from said pseudo random generator, adding said symbol vectors ( r i ) to generate
an encoded message ( m ) and using said encoded message for
embedding said watermark.
Claim 9
Dependent Claim
65 words
The method of claim 8 wherein for each of
said symbols (s i ) said pseudo random generator is used
for generating a pseudo random sequence of numbers (v 1 ,
v 2 , ...), and wherein the value of said symbol (s i ) is
used for selecting a sub-sequence within said pseudo random
sequence for forming said symbol vector ( r i ).
Claim 10
Independent Claim
90 words
The method of one of the claims 8 or 9
comprising the following steps for decoding said watermark: extracting a read-out message ( m ') from said
watermark, said read-out message being a vector having
the same length, if erased elements are replaced by zero,
as said symbol vectors ( r i ), generating all possible values of said symbol
vectors ( r i ) using said pseudo random generator seeded
with said seed and calculating the correlation between
all said possible values and said read-out message ( m ').
Claim 11
Independent Claim
42 words
The method of claims 9 and 10 comprising
the step of calculating the cross-correlation between
said pseudo random sequences of numbers (v 1 , v 2 , ...) and
said read-out message ( m ') for retrieving said symbols
(s i ).
Claim 12
Independent Claim
28 words
The method of one of the preceding claims
comprising the step of encoding a message for being embedded
in said watermark by using symbol based Reed Solomon
codes.
Claim 13
Independent Claim
41 words
The method of one of the preceding claims
characterized in that said step b) further comprises the
step of calculating a logarithm of said cover data set
(CI) before embedding said watermark for embedding said
watermark in a perceptually flat domain.
Claim 14
Dependent Claim
92 words
Method for generating a stego data set
(SI) of a cover data set (CI) especially for step b) of
one of the preceding claims comprising the steps of generating at least one message (IAD CI ), applying a digital signature to said message
(IAD CI ) using an asymmetric cryptographic key pair (p H ,
v H ), generating said stego data set (SI) of said
cover data set (CI) by generating at least one digital
watermark in said cover data set (CI), wherein said watermark
contains said message (IAD CI ).
Claim 15
Dependent Claim
114 words
Method for generating and transmitting a
data set between two parties H and B, especially of one
of the preceding claims, comprising the steps of providing a cover data set (CI) corresponding
to the data set to be transmitted, generating a stego data set (SI) of said
cover data set (CI) at a party H by generating at least
one digital watermark in said cover data set (CI), transmitting said stego data set (SI) to a
registration party (O), and permanently storing certification data (CCD)
at said registration party (O), said certification data
comprising a hash value of said stego data set (SI), a
digital time stamp (TVP) and information designating said
party H.
Claim 16
Dependent Claim
74 words
The method of claim 15 further comprising
the steps of generating a digital signature of said certification
data (CCD) using an asymmetric cryptographic
key pair (ps O , vs O ) of said registration party (O),
transmitting said certification data (CCD) and said digital
signature to said party H, and verifying said digital
signature at said party H by using a public key (vs O ) of
said key pair of said registration party.
Claim 17
Dependent Claim
183 words
Method for generating and verifying a watermark
in a cover data set (CI) representing a cover image,
especially for step b) of one of the preceding
claims, comprising the following steps for generating
said watermark A) calculating the Fourier transform of at
least part of said cover image for generating Fourier
components of said cover image, and B) modulating at least part of said Fourier
components using a template modulation pattern ( T '), C) using the inverse Fourier transform for
generating a stego image, said method further comprising the following steps for
verifying said watermark in a possibly scaled and/or rotated
version of said stego image, D) calculating the Fourier transform of the
possibly scaled and/or rotated version of said stego image
for generating Fourier components of said stego image, E) calculating a log-polar transform of said
Fourier components of said stego image, and F) calculating the cross correlation between
a log-polar transform ( T ) of said modulation pattern ( T ')
and said log-polar transform of said Fourier components
of said stego image for evaluating a scaling and/or rotation
factor.
Claim 18
Dependent Claim
48 words
The method of claim 17 wherein said step
B) further comprises the steps of calculating a log-polar transform of said
components of said cover image for generating log-polar
components, modulating said log polar components using a
log-polar transform ( T ) of said modulation pattern ( T ').
Claim 19
Dependent Claim
86 words
Method for generating a watermark in a
cover data set (CI) representing a cover image especially
for one of the preceding claims, characterized by the
step of dividing said image into a plurality of adjacent
blocks and by the following steps carried out for each
block: calculating the Fourier transform of the
block of the block, and modulating at least part of the magnitude
components of the Fourier transform of the block using a
modulation pattern, wherein the same modulation pattern
is used for all blocks.
Claim 20
Dependent Claim
52 words
The method of claim 19, wherein the modulation
pattern determines values to be added and/or subtracted
for each of said magnitude components and
wherein, at each frequency, the corresponding phase component
of the Fourier transform is used for determining
if said value is to be added or subtracted from said magnitude
component.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.