An implementation of a technology is described herein for deriving robust non-local
characteristics and quantizing such characteristics for blind watermarking of a
digital good. This technology finds the proper balance between minimizing the probability
of false alarms (i.e., detecting a non-existent watermark) and the probability
of misses (i.e., failing to detect an existing watermark). The technology, described
herein, performs quantization index modulation (QIM) based upon non-local characteristics
of the digital good. Non-local characteristics may include statistics (e.g., averages,
median) of a group of individual parts (e.g., pixels) of a digital good. This abstract
itself is not intended to limit the scope of this patent. The scope of the present
invention is pointed out in the appending claims.