US Patent #6,078,664 Z-transform implementation of digital watermarks

Abstract (US Patent #6,078,664 Z-transform implementation of digital watermarks)

Z-transform calculations may be used to encode (and/or decode) carrier signal independent data (e.g., digital watermarks) to a digital sample stream. Deterministic and non-deterministic components of a digital sample stream signal may be analyzed for the purposes of encoding carrier signal independent data to the digital sample stream. The carrier signal independent data may be encoded in a manner such that it is restricted or concentrated primarily in the non-deterministic signal components of the carrier signal. The signal components can include a discrete series of digital samples and/or a discreet series of carrier frequency sub-bands of the carrier signal. Z-transform calculations may be used to measure a desirability of particular locations and a sample stream in which to encode the carrier signal independent data.

US Patent #5,905,800 Method and system for digital watermarking

Abstract (US Patent #5,905,800 Method and system for digital watermarking)

A method for applying a digital watermark to a content signal is disclosed. In accordance with such a method, a watermarking key is identified. The watermarking key includes a binary sequence and information describing application of that binary sequence to the content signal. The digital watermark is then encoded within the content signal at one or more locations determined by the watermarking key.

US Patent #5,889,868 Optimization methods for the insertion, protection, and detection of digital watermarks in digitized data

Abstract (US Patent #5,889,868 Optimization methods for the insertion, protection, and detection of digital watermarks in digitized data)

The implementations of digital watermarks can be optimally suited to particular transmission, distribution and storage mediums given the nature of digitally-sampled audio, video and other multimedia works. Watermark application parameters can be adapted to the individual characteristics of a given digital sample stream. Watermark information can be either carried in individual samples or in relationships between multiple samples, such as in a waveform shape. More optimal models may be obtained to design watermark systems that are tamper-resistant given the number and breadth of existent digitized sample options with different frequency and time components. The highest quality of a given content signal may be maintained as it is mastered, with the watermark suitably hidden, taking into account usage of digital filters and error correction. The quality of the underlying content signals can be used to identify and highlight advantageous locations for the insertion of digital watermarks. The watermark is integrated as closely as possible to the content signal, at a maximum level to force degradation of the content signal when attempts are made to remove the watermarks.

US Patent #5,822,432 Method for human-assisted random key generation and application for digital watermark system

Abstract (US Patent #5,822,432 Method for human-assisted random key generation and application for digital watermark system)

A method for the human-assisted generation and application of pseudo-random keys for the purpose of encoding and decoding digital watermarks to and from a digitized data stream. A pseudo-random key and key application "envelope" are generated and stored using guideline parameters input by a human engineer interacting with a graphical representation of the digitized data stream. Key "envelope" information is permanently associated with the pseudo-random binary string comprising the key. Key and "envelope" information are then applied in a digital watermark system to the encoding and decoding of digital watermarks. The invention includes improvements to the methods of encoding and decoding digital watermarks. Improvements are: separation of the encoder from the decoder, increased information capacity relative to spread spectrum methods, destruction of content resulting from attempts to erase watermarks, detection of presence of watermarks without ability to access watermark information, multi-channel watermark capability, use of various classes of keys for watermark access control, support for alternative encoding, decoding, or other component algorithms, use of digital notary to authenticate and time stamp watermark certificates.

US Patent #5,745,569 Method for stega-cipher protection of computer code

Abstract (US Patent #5,745,569 Method for stega-cipher protection of computer code)

A method for protecting computer code copyrights by encoding the code into a data resource with a digital watermark. The digital watermark contains licensing information interwoven with essential code resources encoded into data resources. The result is that while an application program can be copied in an uninhibited manner, only the licensed user having the license code can access essential code resources to operate the program and any descendant copies bear the required license code.

US Patent #5,687,236 Steganographic method and device

Abstract (US Patent #5,687,236 Steganographic method and device)

An apparatus and method for encoding and decoding additional information into a stream of digitized samples in an integral manner. The information is encoded using special keys. The information is contained in the samples, not prepended or appended to the sample stream. The method makes it extremely difficult to find the information in the samples if the proper keys are not possessed by the decoder. The method does not cause a significant degradation to the sample stream. The method is used to establish ownership of copyrighted digital multimedia content and provide a disincentive to piracy of such material.

US Patent #5,613,004 Steganographic method and device

Abstract (US Patent #5,613,004 Steganographic method and device)

An apparatus and method for encoding and decoding additional information into a stream of digitized samples in an integral manner. The information is encoded using special keys. The information is contained in the samples, not prepended or appended to the sample stream. The method makes it extremely difficult to find the information in the samples if the proper keys are not possessed by the decoder. The method does not cause a significant degradation to the sample stream. The method is used to establish ownership of copyrighted digital multimedia content and provide a disincentive to piracy of such material.

US Patent #5,539,735 Digital information commodities exchange

Abstract (US Patent #5,539,735 Digital information commodities exchange)

A system for the exchange of digital information packets includes an exchange with connectors to allow modular expandable units to connect to the exchange over transmission media. The modular expandable units send digital information packets from one to another over the exchange in response to requests for these digital information packets. The exchange allows for billing and other administrative functions.

US Patent #5,428,606 Digital information commodities exchange

Abstract (US Patent #5,428,606 Digital information commodities exchange)

A system for the exchange of digital information packets includes an exchange with connectors to allow modular expandable units to connect to the exchange over transmission media. The modular expandable units send digital information packets from one to another over the exchange in response to requests for these digital information packets. The exchange allows for billing and other administrative functions.