Multiple transform utilization and applications for secure digital watermarking
First Claim
1. A method for encoding a message into digital information, the digital information including a plurality of digital blocks, comprising the steps of:
- transforming each of the digital blocks into the frequency domain using a fast Fourier transform;
identifying a plurality of frequencies and associated amplitudes for each of the transformed digital blocks;
selecting a subset of the identified amplitudes for each of the digital blocks using a primary mask from a key;
choosing message information from the message using a transformation table generated with a convolution mask; and
encoding the chosen message information into each of said transformed digital blocks by altering the selected amplitudes based on the chosen message information.
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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.
73 Citations
45 Claims
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1. A method for encoding a message into digital information, the digital information including a plurality of digital blocks, comprising the steps of:
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transforming each of the digital blocks into the frequency domain using a fast Fourier transform;
identifying a plurality of frequencies and associated amplitudes for each of the transformed digital blocks;
selecting a subset of the identified amplitudes for each of the digital blocks using a primary mask from a key;
choosing message information from the message using a transformation table generated with a convolution mask; and
encoding the chosen message information into each of said transformed digital blocks by altering the selected amplitudes based on the chosen message information. - View Dependent Claims (3, 5, 6, 7, 8, 9, 10, 12, 14, 15, 16, 17, 25)
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2. A method for encoding a message into digital information, the digital information including a plurality of digital blocks, comprising the steps of:
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transforming each of the digital blocks into the frequency domain using a spectral transform;
identifying a plurality of frequencies and associated amplitudes for each of the transformed digital blocks;
selecting a subset of the identified amplitudes for each of the digital blocks using a primary mask from a key;
choosing message information from the message using a transformation table generated with a convolution mask; and
encoding the chosen message information into each of said transformed digital blocks by altering the selected amplitudes based on the chosen message information. - View Dependent Claims (4, 11, 13)
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18. A method for descaling a digital image using a key, comprising the steps of:
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determining original dimensions of the digital image from the key;
scaling the digital image to the original dimensions;
obtaining a reference subset of pixels from the key; and
comparing the reference subset of pixels with corresponding pixels in the scaled digital image. - View Dependent Claims (20, 21, 22, 23, 24)
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19. A method for descaling audio digital information using a key, comprising the steps of:
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determining original dimensions of the audio digital information from the key;
scaling the audio digital information to the original dimensions;
obtaining a reference subset of audio information from the key; and
comparing the reference subset of audio information with corresponding information in the scaled audio information.
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26. A method of extracting a message from encoded digital information using a predetermined key, comprising the steps of:
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decoding the encoded digital information into digital information, including a plurality of digital blocks, using the predetermined key;
transforming each of the digital blocks into the frequency domain using a fast Fourier transform;
identifying a plurality of frequencies and associated amplitudes for each of the transformed digital blocks;
selecting a subset of the identified amplitudes for each of the transformed digital blocks using a primary mask from the key;
comparing the selected amplitudes with original amplitudes stored in the predetermined key to determine the position of encoded message information; and
assembling the message using the encoded message information and a reverse transformation table. - View Dependent Claims (28)
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27. A method of extracting a message from encoded digital information using a predetermined key, comprising the steps of:
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decoding the encoded digital information into digital information, including a plurality of digital blocks, using the predetermined key;
transforming each of the digital blocks into the frequency domain using a spectral transform;
identifying a plurality of frequencies and associated amplitudes for each of the transformed digital blocks;
selecting a subset of the identified amplitudes for each of the transformed digital blocks using a primary mask from the key;
comparing the selected amplitudes with original amplitudes stored in the predetermined key to determine the position of encoded message information; and
assembling the message using the encoded message information and a reverse transformation table.
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29. A method for descaling a digital signal using a key, comprising the steps of:
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determining original dimensions of the digital signal from the key;
scaling the digital signal to the original dimensions;
obtaining a reference signal portion from the key; and
comparing the reference signal portion with a corresponding signal portion in the scaled signal.
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30. A method for protecting a digital signal comprising the step of:
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creating a predetermined key comprised of a transfer function-based mask set and offset coordinate values of the original digital signal; and
encoding the digital signal using the predetermined key. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 42, 43, 44, 45)
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41. A method for protecting a digital signal, comprising the steps of:
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creating a predetermined key comprised of a transfer function-based mask set and offset coordinate values of the original digital signal;
authenticating the predetermined key containing the correct transfer function-based mask set during playback of the data; and
metering the playback of the data to monitor content.
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Specification