Multiple transform utilization and application for secure digital watermarking

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.

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.   
     
     
         2 - 60 . (canceled)