On Tuesdays the USPTO issues new patents. Both of today's Spotlight Patents concern aspects of digital watermarking. Assigned to Intertrust, the first patent addresses techniques for encoding and protecting data using digital signature and watermarking. Assigned to DTS, the second patent addresses a temporally accurate watermarking system and method of operation.
8,099,601, "Methods and systems for encoding and protecting data using digital signature and watermarking techniques," assigned to Intertrust.
Systems and methods are provided for protecting and managing electronic data signals that are registered in accordance with a predefined encoding scheme, while allowing access to unregistered data signals. In one embodiment a relatively hard-to-remove, easy-to-detect, strong watermark is inserted in a data signal. The data signal is divided into a sequence of blocks, and a digital signature for each block is embedded in the signal via a watermark. The data signal is then stored and distributed on, e.g., a compact disc, a DVD, or the like. When a user attempts to access or use a portion of the data signal, the signal is checked for the presence of a watermark containing the digital signature for the desired portion of the signal. If the watermark is found, the digital signature is extracted and used to verify the authenticity of the desired portion of the signal. If the signature-containing watermark is not found, the signal is checked for the presence of the strong watermark. If the strong watermark is found, further use of the signal is inhibited, as the presence of the strong watermark, in combination with the absence or corruption of the signature-containing watermark, provides evidence that the signal has been improperly modified. If, on the other hand, the strong mark is not found, further use of the data signal can be allowed, as the absence of the strong mark indicates that the data signal was never registered with the signature-containing watermark.
8,099,285, "Temporally accurate watermarking system and method of operation," assigned to DTS, Inc.
A system for identifying audio data is provided. The system includes a transform system receiving left channel audio data and right channel audio data and generating a plurality of frequency bins of left channel magnitude data, left channel phase data, right channel magnitude data and right channel phase data. A watermarking system receives watermarking data and modifies predetermined frequency bins of the left channel phase data and the right channel phase data to encode the watermarking data. A magnitude system receives the left channel magnitude data and the right channel magnitude data and increases the left channel magnitude data and the right channel magnitude data for one or more of the predetermined frequency bins to a threshold level if the left channel magnitude data and the right channel magnitude data for the corresponding frequency bin is less than the threshold level.