title: Covert Underwater Acoustic Communication Using Marine Ambient Noise Without Detectable Features
abstract: Learning from steganography, this study considers ocean ambient noise as a carrier and proposes a covert underwater acoustic communication scheme without detectable and repetitive features. We modulate the information in the parameters of the steganography operation rather than the specific signal waveforms. The steganography operation mainly includes three steps: symmetrical division, phase rotation, and time–domain inversion. The rotation phases are related to the transmitted information. The 
journal: Journal of Marine Science and Engineering