Multiple transform utilization and application for secure digital watermarking
View Patent ↗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 protecting a digital signal comprising the steps of:
creating a predetermined key comprised of a transfer function-based mask set and offset coordinate values of the digital signal in its original form;
selecting a 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;
using a digital watermarking technique to embed information that identifies ownership, use, or other information about the digital signal, into the digital signal; and wherein said step of validating is dependent on validation of the embedded information; and
encoding the digital signal using the predetermined key.
2. A method for protecting a digital signal comprising the steps of:
creating a predetermined key comprised of a transfer function-based mask set and offset coordinate values of the digital signal in its original form wherein the digital signal is a bit stream and the method further comprising the steps of:
generating a plurality of mask sets to be used for encoding, including a random primary mask, a random convolution mask and a random start of a message delimiter wherein generating the plurality of mask sets further comprises:
obtaining a transfer function to be implemented;
generating a message bit stream to be encoded;
loading the message bit stream, a stega-cipher map truth table, a primary mask, a convolution mask and a start of a message delimiter into memory;
initializing the state of a primary mask index, a convolution mask index, and a message bit index for randomization;
setting a message size equal to the total number of bits in the message bit stream; and
encoding the digital signal using the predetermined key.
3. A method for protecting a digital signal comprising the steps of:
creating a predetermined key comprised of a transfer function-based mask set and offset coordinate values of the digital signal in its original form wherein the digital signal is a bit stream and further comprising the steps of:
generating a mask set to be used for encoding, the mask set including a random primary mask, a random convolution mask, and a random start of a message delimiter wherein generating the mask set further comprises:
obtaining a message to be encoded;
compressing and encrypting the message if desired;
generating a message bit stream to be encoded;
loading the message bit stream, a stega-cipher map truth table, a primary mask, a convolution mask and a start of a message delimiter into memory;
initializing the state of a primary mask index, a convolution mask index, and a message bit index for randomization;
and setting the message size equal to the total number of bits in the message bit stream; and
encoding the digital signal using the predetermined key.
4. The method of claim 2 , wherein the digital signal has a plurality of windows, further comprising the steps of:
calculating over which windows in a sample stream of the digital signal will be encoded;
computing a secure one way hash function of the information in the calculated windows,
the hash function generating hash values insensitive to changes in the sample induced by a stega-cipher;
encoding the generated hash values in an encoded stream of data.
5. A method for protecting a digital signal comprising the steps of:
creating a predetermined key comprised of a transfer function-based mask set and offset coordinate values of the digital signal in its original form;
selecting a 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 wherein said step of selecting comprises the steps of:
collecting a series of random bits derived from keyboard latency intervals in random typing;
processing the initial series of random bits through an MD5 algorithm;
using the results of the MD5 algorithm to seed a triple-DES encryption loop;
cycling through the triple-DES encryption loop, extracting the least significant bit of each result after each cycle;
concatenating the triple-DES output bits into series of random bits; and
encoding the digital signal using the predetermined key.