Multiple transform utilization and applications for secure digital watermarking
OwnerScott A. Moskowitzinventor
Life of this patent
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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.
Claims21
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.
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 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.
A method of extracting a message from encoded digital information using a predetermined key, comprising the steps of:
- 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.
A method of extracting a message from encoded digital information using a predetermined key, comprising the steps of:
- 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.
Dependencies are inferred from the claim text.