CIRCUMVENTION OF WATERMARK ANALYSIS IN A HOST CONTENT

摘要

Methods and devices are provided to thwart analysis of a watermarking system by preventing analysis of watermarks in a host content. Upon receiving a content at a watermark embedding device, the content is analyzed to ascertain whether one or more test features are present in at least a first portion of the received content. When the analysis reveals that one or more test features are present, embedding of watermarks in at least the first portion of the received content is disabled. The test features of interest include a temporal, a spatial and/or a frequency characteristic such that, if a region of the content that includes test feature is embedded with a watermark, at least one characteristic of the embedded watermark is detectable upon analysis of that region. The test feature can, for example, approximate an impulse signal, a step function signal or a pure sinusoidal signal.

主权项

1. A method for thwarting circumvention attempts on a watermarking system, the method comprising:
(a) receiving a content at a content handling device that includes embedded watermarks; (b) extracting an embedded watermark from a segment of the received content, the extracted watermark being suitable for reporting to a user of the content handling device; (c) using a probability value to make a determination as to whether or not to report the extracted watermark; (d) upon a determination to report the extracted watermark, reporting a value of the extracted watermark or a presence of the extracted watermark; (e) upon a determination not to report the extracted watermark, not reporting information related to the extracted watermark; and (f) repeating operations (b) through (e) for one or more additional embedded watermarks in the received content to create an uncertainty as to whether or not all extractable watermarks that are embedded in the content are reported.