A watermarking method converts a watermark message into a Frequency Shift Keying
(FSK) signal and embeds the FSK signal in a host signal. The spectral properties
of the FSK watermark signal facilitate its detection, even in applications where
the watermarked signal is corrupted. Because of these properties, the FSK watermark
signal can perform the dual function of identifying the watermark's presence and
orientation in potentially corrupted media, and also conveying a hidden message
in the host signal. Such a watermark may be referred to as a self-orienting watermark.