TUTORIAL SESSION

Information Hiding in Audio Signals for Watermarking, Steganography and Covert Communication Applications

Prof. Kaliappan Gopalan
Purdue University Calumet, USA
gopalan@purduecal.edu

Abstract

Steganography is concerned with embedding information in a media (cover) signal in an imperceptible manner. Applications of steganography include watermarking for copyright protection and authentication, data hiding for secure storage and transmission, and covert
communication using unclassified channels. Indiscernible hiding of information in an audio
signal is more challenging than invisible modification of an image or video signal due to the
wide dynamic range of human audibility in frequency and power level. In spite of this challenge,
human auditory system imperfections, which lead to psychoacoustic masking effects in hearing
and perception, can be exploited for unnoticeable modifying of a cover audio signal in accordance with a given piece of covert information. Since the modification is carried out in the
masked regions of perceptibility, the information-embedded audio (stego) signal appears to be
the same as the original signal in spectrogram and perceptual quality. Successful embedding
depends, among others, on the discernibility of any difference between the original cover signal
and the stego signal, robustness of the hidden information to noise, and recovery key that does
not require the original cover audio signal.
This presentation will provide an overview of psychoacoustic masking-based audio
steganography with an emphasis on the newly developed tone insertion techniques in the spectral
and cepstral domains, and their extension to image embedding.

Objectives

The objectives of the tutorial are to provide the audience an overview of multimedia embedding of information and leave them with an understanding of the basics of key-based audio signal modification for imperceptible and robust hiding of data with oblivious recovery.

Background Knowledge Expected of the Participants

Basic understanding of spectral domain representation of signals, DFT and IDFT.

Qualifications of the Instructor(s)

K. ‘Gopal’ Gopalan has been with the Department of Electrical and Computer Engineering at Purdue University Calumet, Hammond, Indiana since 1985, currently holding the positions of Professor and Coordinator of the Engineering Graduate Program. He has been awarded the Outstanding Sponsored Research Scholar Award in 2009 and the Outstanding Faculty Scholar Award in 2002 and 2010, all at Purdue University Calumet. He received his Bachelor’s degree in Electrical Engineering from P.S.G. College of Technology (University of Madras), Coimbatore, India, Master’s degree in Electrical Engineering from the Indian Institute of Technology, Kanpur (IITK), India, and Ph.D. degree in Engineering from the University of Akron, Akron, Ohio. From 1974 to 1979, he was employed as a research engineer at IITK developing research instrumentation systems.
From 1987 to 1995 he conducted research in the areas of signal and image processing for
nondestructive evaluation of advanced materials at Argonne National Laboratory, Argonne,
Illinois, first as a summer faculty research participant and later as a consultant. In addition, he
has been a summer faculty research associate at Wright-Patterson Air Force Base, Ohio, and the
Air Force Research Laboratory (AFRL), Rome, New York. His research in speech analysis,
speaker recognition, audio steganography, and keyword recognition has been funded by AFRL,
Rome, NY. He has received three U.S. patents, all on audio steganography and data embedding.
Gopalan gave keynote addresses on Keyword Spotting in Speech Communication – An Overview
at (a) the 8th International Conference on Computing, Communications and Control
Technologies, Orlando, FL, in April 2010, and (b) the International Workshop on Multimedia
Streaming, Kochi, India, in July 2011. He presented a tutorial on audio watermarking and
steganography at the 55th International Midwest Symposium on Circuits and systems (IEEE
MWSCAS 2012), Boise, Idaho, in August 2012, and a one-hour talk on Information Hiding in
Audio Signals at the IEEE Chicago Section meeting in November 2012. In addition, he has
given several invited presentations at universities and colleges in Australia, India, Malaysia and
Singapore.
Gopalan is a Senior Member of the IEEE and is the author of two textbooks, Introduction to Digital Microelectronic Circuits (Irwin/McGraw-Hill, 1996), and Introduction to Signal and
System Analysis (Cengage, 2009).

K. ‘Gopal’ Gopalan is a professor of Electrical and Computer Engineering at Purdue University Calumet, Hammond, Indiana. He has been awarded the Outstanding Sponsored Research Scholar Award in 2009 and the Outstanding Faculty Scholar Award in 2002 and 2010, all at Purdue University Calumet.
From 1987 to 1995 he conducted research in the areas of signal and image processing for nondestructive evaluation of advanced materials at Argonne National Laboratory, Argonne, Illinois, first as a summer faculty research participant and later as a consultant. In addition, he has been a summer faculty research associate at Wright-Patterson Air Force Base, Ohio, and the Air Force Research Laboratory (AFRL), Rome, New York. His research in speech analysis, speaker recognition, audio steganography, and keyword recognition has been funded by AFRL, Rome, NY. He has received three U.S. patents, all on audio steganography and data embedding.
Gopalan gave keynote addresses on Keyword Spotting in Speech Communication – An Overview at (a) the 8th International Conference on Computing, Communications and Control Technologies, Orlando, FL, in April 2010, and (b) the International Workshop on Multimedia Streaming, Kochi, India, in July 2011. He presented a tutorial on audio watermarking and steganography at the 55th International Midwest Symposium on Circuits and systems (IEEE MWSCAS 2012), Boise, Idaho, in August 2012, and a one-hour talk on Information Hiding in Audio Signals at the IEEE Chicago Section meeting in November 2012.
Gopalan is a Senior Member of the IEEE and is the author of two textbooks, Introduction to Digital Microelectronic Circuits (Irwin/McGraw-Hill, 1996), and Introduction to Signal and System Analysis (Cengage, 2009).