Method and apparatus for embedding authentication information within digital data
First Claim
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1. A method for marking a digital data block, said digital data block comprising a digital representation of an object, said digital data block containing a digital object having an initial basic format, comprising the steps of:
- modifying said digital data block to contain an embedded authentication stamp;
modifying the data comprising the digital data block; and
user determining whether any additional modifications have been made to said digital data block;
wherein the basic format of the digital object after modifying said digital data block to contain an embedded authentication stamp and modifying the data comprising the digital data block is the same as said initial basic format;
wherein said authentication stamp is obscured relative to the magnitude of said unmodified data.
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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.
975 Citations
20 Claims
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1. A method for marking a digital data block, said digital data block comprising a digital representation of an object, said digital data block containing a digital object having an initial basic format, comprising the steps of:
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modifying said digital data block to contain an embedded authentication stamp; modifying the data comprising the digital data block; and user determining whether any additional modifications have been made to said digital data block; wherein the basic format of the digital object after modifying said digital data block to contain an embedded authentication stamp and modifying the data comprising the digital data block is the same as said initial basic format; wherein said authentication stamp is obscured relative to the magnitude of said unmodified data. - View Dependent Claims (2, 3)
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4. A method for marking a digital data block comprising a digital representation of an object, comprising the steps of:
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calculating a digital signature for said digital data block in accordance with a selected calculation technique; appending said digital signature to a meta-data stream; encrypting said meta-data stream; embedding said encrypted meta-data stream into said digital data block; and user determining whether any additional modifications have been made to said digital data block; wherein said authentication stamp is obscured relative to the magnitude of said unmodified data. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for embedding information into a digital data block comprising a digital representation of an object, comprising the steps of:
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adding information to said digital data block by embedding said information into said data block and thereby deliberately introducing errors in said modified digital data block, wherein the information includes an authentication stamp or any sequence of bits that encrypt information for a receiver of said data block, and wherein when said digital data block is converted into a non-digital form said embedded errors are not exhibited; and detecting any additional errors introduced into the digital data block after the information embedding step is completed. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification