A
system for determining the amount of
processing that has been applied to watermarked
signal. A steganographic
signal is provided that includes an original
signal and an embedded fragile
watermark. The fragile
watermark is characterized by a low energy and a high redundancy in comparison to a robust
watermark. The steganographic signal is communicated over a distribution channel to a decoder. At the decoder, a measure of a presence of the fragile watermark in the acquired steganographic signal is provided, along with an estimate of the
fragility profile of the fragile watermark for this particular original signal. Based on these factors, a estimate is made of the amount of
processing that the steganographic signal has undergone. This
processing can include, for example, A / D and D / A conversions,
resampling, band-limiting, perceptual compression / decompression, etc. Optionally, the
fragility profile is derived prior to the distribution of the content and communicated by the steganographic signal for
recovery by the decoder. Furthermore, a robust watermark may be provided in the steganographic signal that, e.g., designates the presence of the fragile watermark to a decoder.