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US 6,353,672 B1Granted
Steganography using dynamic codes
AssigneeDigimarc Corporation
InventorGeoffrey B. Rhoads
Life of this patent
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AssigneeDigimarc Corporation
InventorGeoffrey B. Rhoads
Estimating the term…
An input content signal—representing audio or video—is steganographically encoded to hide plural-bit auxiliary data therein. The encoding operation changes over time, e.g., by using different “key” data for successive portions of the content signal. In some embodiments, the key data used in one portion of the signal is a function of auxiliary data decoded from a preceding portion. Consequently, to successfully decode the auxiliary data, the decoder must have successfully decoded a previous portion. In essence, decoding instructions are sent “on the fly” in such embodiments. In some embodiments, the auxiliary data is changed in temporally adjoining portions of the content signal—e.g., in successive frames of video or blocks of audio. In other embodiments, the key is changed less frequently, e.g., on a daily basis. External events may also trigger changing of the key data.
A method of processing a digital signal comprised of plural successive portions, said portions representing human-perceptible audio or image information, comprising:
A method of steganographically encoding auxiliary data within a signal comprised of plural successive portions, said portions representing human-perceptible audio or image information, characterized in that:
A method of steganographically decoding auxiliary data from a signal comprised of plural successive portions, said portions representing human-perceptible audio or image information, the steganographically decoding requiring use of reference data in order to discern the auxiliary data from the signal, characterized in that the reference data changes on the fly, depending on auxiliary data decoded from a preceding portion.
In a method of steganographic decoding, an improvement comprising steganographically decoding data from a first portion of the encoded information that provides information necessary to steganographically decode a following portion of the encoded information.
In a method of steganographic encoding of content data with auxiliary data, an improvement comprising steganographically encoding data within a first portion of the content data that provides information necessary to steganographically decode a following portion of the content data.
Dependencies are inferred from the claim text.