Encoder and encoding method for electronic watermark, decoder and decoding method for electronic watermark, encoding and decoding program for electronic watermark, and recording medium for recording such program
First Claim
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1. An encoder for forming electronic watermark information which detects tampering in a digital content, and limits a part of said tampering based on said electronic watermark embedded in said digital content, comprising:
- means for dividing a subject digital content into multiple blocks;
means for independently forming electronic watermark information in the individual blocks;
means for dividing the blocks to be divided such that a region of the block overlaps blocks neighboring on the upper, lower, left, and right sides in place of said means for dividing said digital content into multiple blocks; and
means for associating the electronic watermark information formed by the means for independently forming electronic watermark information in the individual blocks with each other by means of the overlap region between said blocks,said electronic watermark being formed so as to detect an exchange between said blocks as tampering.
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Abstract
Disclosed is an encoder for forming electronic watermark information which allows detecting tampering of a digital content based on an electronic watermark embedded in the digital content, and limiting said tampered part. This encoder comprises means for dividing a subject digital content into multiple blocks, and means for independently forming the electronic watermark information in the individual blocks.
38 Citations
38 Claims
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1. An encoder for forming electronic watermark information which detects tampering in a digital content, and limits a part of said tampering based on said electronic watermark embedded in said digital content, comprising:
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means for dividing a subject digital content into multiple blocks; means for independently forming electronic watermark information in the individual blocks; means for dividing the blocks to be divided such that a region of the block overlaps blocks neighboring on the upper, lower, left, and right sides in place of said means for dividing said digital content into multiple blocks; and means for associating the electronic watermark information formed by the means for independently forming electronic watermark information in the individual blocks with each other by means of the overlap region between said blocks, said electronic watermark being formed so as to detect an exchange between said blocks as tampering. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An encoding method for electronic watermark for forming electronic watermark information which detects tampering in a digital content, and limits a part of said tampering based on said electronic watermark embedded in said digital content, comprising the steps of:
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dividing a subject digital content into multiple blocks; independently forming electronic watermark information in the individual blocks; dividing the blocks to be divided such that a region of the block overlaps blocks neighboring on the upper, lower, left, and right sides corresponding to the means for dividing the digital content into multiple blocks; and associating the electronic watermark information formed by the means for independently forming electronic watermark information in the individual blocks with each other by means of the overlap region between said blocks, said electronic watermark being formed so as to detect an exchange between said blocks as tampering. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A computer program product storing program instructions for encoding to form electronic watermark information which detects tampering in a digital content, and limits a part of said tampering based on said electronic watermark embedded in said digital content, and for decoding said electronic watermark for showing a tampered part when said tampered part is detected, which when executed by an information processing apparatus, result in said information processing apparatus performing steps comprising:
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dividing a subject digital content into multiple blocks; independently forming electronic watermark information in the individual blocks; reading out the electronic watermark information individually for the multiple divided blocks; and decoding said electronic watermark information, and then said information processing apparatus detects a tempered part, limits said tampered part to a block, and shows the tampered part for the individual blocks. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38)
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Specification