# US 8,542,831 B2 · Multiple transform utilization and application for secure digital watermarking

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- Number: US 8,542,831 B2
- Document ID: US8542831B2
- Status: Granted
- Kind: B2
- Application number: 12/799,894
- Filed: 2010-05-04
- Published: 2010-09-02
- Granted: 2013-09-24
- Earliest claimed: 1998-04-02
- Applicants: Scott A. Moskowitz
- Inventors: Scott A. Moskowitz
- Web page: https://patentgrep.com/patent/US8542831B2

## CPC

- H04L 9/14: using a plurality of keys or algorithms
- G06T 1/0028: {Adaptive watermarking, e.g. Human Visual System [HVS]-based watermarking}
- G06T 1/005: {Robust watermarking, e.g. average attack or collusion attack resistant}
- G06T 1/0057: {Compression invariant watermarking}
- G06T 1/0064: {Geometric transfor invariant watermarking, e.g. affine transform invariant}
- H04L 9/0819: {Key transport or distribution, i.e. key establishment techniques where one party creates or otherwise obtains a secret value, and securely transfers it to the other(s) (network architectures or network communication protocols for key distribution in a packet data network H04L63/062)}
- H04N 1/3216: {using Fourier transforms}
- H04N 1/32187: {with selective or adaptive application of the additional information, e.g. in selected frequency coefficients}
- H04N 1/32309: {in colour image data}
- G06T 2201/0051: Embedding of the watermark in the spatial domain
- G06T 2201/0052: Embedding of the watermark in the frequency domain
- G06T 2201/0053: Embedding of the watermark in the coding stream, possibly without decoding; Embedding of the watermark in the compressed domain
- G06T 2201/0061: Embedding of the watermark in each block of the image, e.g. segmented watermarking
- G06T 2201/0063: in relation to collusion attacks, e.g. collusion attack resistant
- G06T 2201/0065: Extraction of an embedded watermark; Reliable detection
- G06T 2201/0083: whereby only watermarked image required at decoder, e.g. source-based, blind, oblivious
- H04L 2209/04: Masking or blinding
- H04L 2209/043: of tables, e.g. lookup, substitution or mapping
- H04L 2209/046: of operations, operands or results of the operations
- H04N 2201/3233: of authentication information, e.g. digital signature, watermark
- H04N 2201/324: Selecting a particular authentication information from amongst a plurality of different authentication information
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

Multiple transform utilization and applications for secure digital watermarking. In one embodiment of the present invention, digital blocks in digital information to be protected are transformed into the frequency domain using a fast Fourier transform. A plurality of frequencies and associated amplitudes are identified for each of the transformed digital blocks and a subset of the identified amplitudes is selected for each of the digital blocks using a primary mask from a key. Message information is selected from a message using a transformation table generated with a convolution mask. The chosen message information is encoded into each of the transformed digital blocks by altering the selected amplitudes based on the selected message information.

## Claims

### Claim 1

A method for protecting a digital signal, comprising:
obtaining a digital signal comprising a plurality of digital blocks;
transforming, using a processor, each of the digital blocks into the frequency domain using a spectral transform;
identifying a plurality of frequencies and associated amplitudes for each set of the transformed digital blocks;
selecting a subset of the identified amplitudes based on the survivability of message information against signal manipulation;
choosing said subset of the identified amplitudes for each of the digital blocks using a primary mask from a key;
choosing message information using a transformation table generated with a convolution mask; and,
encoding, using a processor, the chosen message information into said transformed digital blocks by altering the selected amplitudes based on the chosen message information.

### Claim 2 (depends on 1)

The method of claim 1, wherein the survivability of the message information against signal manipulation is determined prior to encoding.

### Claim 3 (depends on 1)

The method of claim 1, wherein said encoding results in an encoded digital signal, further comprising: obtaining a copy of the encoded digital signal; obtaining a key; analyzing the encoded digital signal with one or more of the following: a) analysis of manipulations of the encoded digital signal b) spectral transform analysis of the encoded digital signal c) spectral transform analysis of a portion of the encoded digital signal or d) combinations thereof; and determining the message information based on said analysis.

### Claim 4 (depends on 1)

The method of claim 1, wherein the step of choosing comprises choosing from members selected in the selecting step.

### Claim 5 (depends on 1)

The method of claim 1 further comprising:
creating a predetermined key comprised of output of an operation performed on a transfer function-based mask set and offset coordinate values of said digital signal; and
wherein said encoding comprises using the predetermined key.

### Claim 6 (depends on 5)

The method of claim 5, wherein said digital signal represents a continuous analog waveform.

### Claim 7 (depends on 5)

The method of claim 5, wherein the predetermined key comprises a plurality of mask sets.

### Claim 8 (depends on 5)

The method of claim 5, wherein the mask set is ciphered by a key pair comprising a public key and a private key.

### Claim 9 (depends on 5)

The method of claim 5, further:
using a digital watermarking technique to encode information that identifies ownership, use, or other information about said digital signal, into said digital signal.

### Claim 10 (depends on 5)

The method of claim 5, wherein said digital signal represents a still image, audio or video.

### Claim 11 (depends on 5)

The method of claim 5, further comprising:
selecting the mask set, including one or more masks having random or pseudo-random series of bits; and validating the mask set at the start of the transfer function-based mask set.

### Claim 12 (depends on 11)

The method of claim 11, wherein said step of validating comprises: comparing a hash value computed at the start of the transfer function-based mask set with a determined transfer function of the hash value.

### Claim 13 (depends on 11)

The method of claim 11, wherein said step of validating comprises the step of: comparing a digital signature at the start of the transfer function-based mask set with a determined transfer function of the digital signature.

### Claim 14 (depends on 5)

The method of claim 5, further comprising:
computing a secure one way hash function of carrier signal data in said digital signal, wherein the hash function is insensitive to changes introduced into the carrier signal for the purpose of carrying the transfer function-based mask set.

### Claim 15 (depends on 5)

The method of claim 5 wherein said creating said predetermined key comprises using said processor.

### Claim 16 (depends on 1)

The method of claim 1 further comprising:
creating a predetermined key comprised of output of an operation performed on a transfer function-based mask set and offset coordinate values of the digital signal;
authenticating, using a processor, the predetermined key containing the correct transfer function-based mask set during playback of data; and
metering the playback of the data to monitor content.

### Claim 17 (depends on 16)

The method of claim 16 wherein said creating said predetermined key comprises using said processor.

### Claim 18 (depends on 1)

The method of claim 1 further comprising:
creating a key comprised of: a) a map to encode at least one message and b) a reference subset of said digital signal, wherein said reference subset is a subset of a transform of a subset of said digital signal; and
wherein said encoding comprises encoding said message information into said transformed digital blocks according to said map, thereby creating an encoded digital signal.

### Claim 19 (depends on 18)

The method of claim 18, further comprising: using the key to access at least one message that has been encoded into the encoded digital signal without having to compare the encoded digital signal to said digital signal.

### Claim 20 (depends on 18)

The method of claim 18, wherein the reference subset of said initial digital signal includes one or more of the following group: a) amplitude b) frequency c) time d) pitch or e) dimensions of said digital signal or f) combinations thereof.

### Claim 21 (depends on 18)

The method of claim 18, wherein the message information includes one or more of the following group: a) authentication information b) tamper proofing information c) non-repudiation information d) ownership information e) information for authorizing use f) unrelated random noise or g) information regarding relationships between the message and the key or h) combinations thereof.

### Claim 22 (depends on 18)

The method of claim 18, further comprising: using the key to enable a) play b) display c) transmission d) authorization e) validation or f) use of the encoded digital signal or g) combinations thereof.

### Claim 23 (depends on 18)

The method of claim 18, further comprising: using the key to enable authentication of either 1) the message 2) the encoded digital signal or 3) both the message and the encoded digital signal.

### Claim 24 (depends on 18)

The method of claim 18 wherein said creating said key comprises using said processor.