Abstract: A system (100) for watermarking digital data includes a watermark etching subsystem (105) and a watermark extraction subsystem (110). The watermark etching subsystem (105) obtains a matrix of digital data values, selects windows including a plurality of data values from the matrix, specifies a parameter that indicates an acceptable amount of variation in the data values, and etches watermark bits in each window of data values using the specified parameter. The watermark extraction subsystem (110) obtains a matrix of digital data values containing an etched watermark, selects windows comprising a plurality of data values from the matrix, and extracts watermark bits from each window of data values using the specified parameter.