US 6,330,672 B1 · Method and apparatus for watermarking digital bitstreams

Abstract

A signal is encoded, for example, perceptually and, during or after the perceptual coding process, a digital watermark is inserted into a quantized digital information signal resulting from the perceptual coding process in such a manner that its insertion is imperceptible to one later listening to, displaying or otherwise utilizing the information signal. Moreover, the digital watermark may be inserted in accordance with a key indicative of the location of the mark in the digitally encoded signal. The key may be protected with a trusted entity and distributed in such a manner as to be not detectable by a pirate. Consequently, the key may be utilized at watermarking apparatus that can be located anywhere in the distribution channel of a copyright protected work. The key may be embedded in a secure microprocessor of validating apparatus at a point of distribution or even at a point of sale. In this manner, when or after a digital bitstream is fixed in a medium of expression or broadcast, the watermark can be applied at the time of fixing in a copy, thus validating an original legitimate copy. For example, a compact disc recording may be validated at the point of sale as an authorized copy through watermarking (validating) apparatus according to the present invention or, at the time of broadcast over radio frequencies or distribution via the Internet, information may be watermarked. In this manner, even though a work may be pirated, further information may be included or otherwise indicated by the watermark to assist in, not only recognizing a pirated work and the original from which the pirate copy was produced, but the identity of the pirate who later makes an unauthorized copy of the original.

Claims36

Dependent claims

Apparatus for inserting a digital watermark into protected information comprises

a transformation function of a perceptual coder for coding an information signal representative of the protected information,
a watermark location selector responsive to the perceptual coder for selecting a location for inserting a digital watermark, said watermark location selector including a logical gate responsive to a random number generator, said random number generator, responsive to a seed and a selection of a watermark overhead, for outputting a binary sequence,
a digital watermark generator for generating a digital watermark sequence responsive to a plurality of predetermined watermark parameters and
a quantizer of the perceptual coder responsive to the digital watermark generator and the watermark location selector for inserting a digital watermark at selected locations within an output bitstream, said output bitstream including the perceptually coded information signal.

1 more element

A method for inserting a digital watermark into protected information comprising the steps of

perceptually encoding an information signal representative of the protected information,
selecting, responsive to the perceptual coding step, a location for inserting a digital watermark including the step of generating a binary sequence using a random number generator responsive to selecting a seed and a watermark overhead and providing said binary sequence to a logical gate,
generating a digital watermark sequence responsive to a plurality of watermark parameters for input to said logical gate, and
during perceptual coding, quantizing the information signal to insert the generated digital watermark at selected locations within an output bitstream, said output bitstream including the perceptually coded information signal.

1 more element

Dependencies are inferred from the claim text.

Method and apparatus for watermarking digital bitstreams

Life of this patent

Method and apparatus for watermarking digital bitstreams

Life of this patent

Abstract

Claims36