초록 ▼

A watermarking procedure wherein each of a set of copies of the work has a slightly-modified form of a “baseline”watermark that is placed within a critical region of the data. The slight variations in the watermarks, however, are not perceptually visible and do not interfere with the work. If multip

A watermarking procedure wherein each of a set of copies of the work has a slightly-modified form of a “baseline”watermark that is placed within a critical region of the data. The slight variations in the watermarks, however, are not perceptually visible and do not interfere with the work. If multiple persons collude to attempt to create an “illicit”copy of the work (i.e., a copy without a watermark), however, at least one of the modified watermarks is present in the copy, thereby identifying both the illicit copy and the copier.

대표청구항 ▼

A watermarking method, comprising the steps of: (a) generating a digital string from the work to form a baseline watermark; (b) generating a set of watermarks each having a predetermined relationship to the baseline watermark; and (c) inserting a respective one of the set of watermarks into a respec

A watermarking method, comprising the steps of: (a) generating a digital string from the work to form a baseline watermark; (b) generating a set of watermarks each having a predetermined relationship to the baseline watermark; and (c) inserting a respective one of the set of watermarks into a respective copy of the work to create a watermarked copy uniquely identified by the respective one of the set of watermarks; and (d) repeating step (c) at least m times to create a set of m watermarked copied, each having a different one of the set of watermarks therein, such that if a subset of said m watermarked copies are averaged to produce an illicit copy of the work, at least one of the set of watermarks is detectable in the illicit copy.