Method and apparatus for embedding authentication information within digital data
First Claim
Patent Images
1. An apparatus for authenticating an image data block, comprising:
- a frame sequence counter;
a scan line counter;
an error correction accumulator adapted to generate a digital signature;
a last line error correction register;
a multiplexor for selecting either of a scan line value from said scan line counter and a frame sequence value from said frame sequence counter as an embedded image data block bit pattern; and
a controller for recognizing each frame and each scan line in said image data block;
said controller routes image pixels to a selected one of said frame sequence counter and said scan line counter, and to send an error correction code from said error correction accumulator to said last line error correction register if an end of a frame is encountered;
said controller comprising;
means for routing each image pixel in said image data block to said controller;
means for generating an authentication code by prepending either of a scan line value from said scan line counter and a frame sequence value from said frame sequence counter to said digital signature; and
means for embedding said authentication code into said image data block, wherein said authentication code is offset from the beginning of either of said image scan line and said frame.
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Abstract
Arbitrary digital information is embedded within a stream of digital data, in a way that avoids detection by a casual observer and that allows a user to determine whether the digital data have been modified from their intended form. The embedded information may only be extracted as authorized and may be used to verify that the original digital data stream has not been modified.
264 Citations
8 Claims
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1. An apparatus for authenticating an image data block, comprising:
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a frame sequence counter; a scan line counter; an error correction accumulator adapted to generate a digital signature; a last line error correction register; a multiplexor for selecting either of a scan line value from said scan line counter and a frame sequence value from said frame sequence counter as an embedded image data block bit pattern; and a controller for recognizing each frame and each scan line in said image data block;
said controller routes image pixels to a selected one of said frame sequence counter and said scan line counter, and to send an error correction code from said error correction accumulator to said last line error correction register if an end of a frame is encountered;
said controller comprising;means for routing each image pixel in said image data block to said controller; means for generating an authentication code by prepending either of a scan line value from said scan line counter and a frame sequence value from said frame sequence counter to said digital signature; and means for embedding said authentication code into said image data block, wherein said authentication code is offset from the beginning of either of said image scan line and said frame.
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2. A method for authenticating an image data block, comprising the steps of:
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generating a digital signature with an error correction accumulator; selecting either of a scan line value from a scan line counter and a frame sequence value from a frame sequence counter as an embedded image data block bit pattern; recognizing each frame and each scan line in said image data block; routing image pixels to a selected one of said frame sequence counter and said scan line counter; sending an error correction code from said error correction accumulator to said last line error correction register if an end of a frame is encountered; routing each image pixel in said image data block to a controller; generating an authentication code by prepending either of a scan line value from said scan line counter and a frame sequence value from said frame sequence counter to said digital signature; and embedding said authentication code into said image data block, wherein said authentication code is offset from the beginning of at least-one of a scan line and a frame in said image data block.
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3. A method for embedding information into a digital data block, comprising the steps of:
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deliberately introducing errors into a digital data block to embed the information into the data block, wherein the information is any sequence of bits that encode knowledge of interest to a receiver of the data block, and said errors do not change the basic format of the digital data block and are not readily noticeable when the digital data block is converted into a non-digital form; and detecting any errors introduced into the digital data block after the information embedding step is completed. - View Dependent Claims (4, 5, 6, 7, 8)
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Specification