Spectral Magnitude Speech Steganography

Abstract

This paper presents a speech-hiding framework that exploits spectral properties of the Fourier magnitude and phase of digital speech signals for the purpose of hiding secret speech messages inside other speech signals for secure transmissions over unsecured networks. The technique used exploits low-pass spectral properties of the speech magnitude spectrum to embed a secret speech signal in the low-amplitude-high-frequency regions of the host speech signal's spectral magnitude. Experimental evaluations on real male and female voice segments show that our technique is capable of hiding one speech message inside another host speech segment to produce a stego speech segment that is indistinguishable from the original host speech, while being able to extract the hidden speech message without any perceived degradations in quality.

Speech Bandwidth Extension Using Data Hiding Based on Discrete Hartley Transform Domain

“…TDDH is robust signal domain speech steganography that converts a binary signal into a hidden vector and embeds it into a magnitude spectrum in the high-frequency bandwidth of 3.4-4 kHz, not depending on the power of the NB speech signal. Since human hearing is little sensitive to the distortion of the magnitude spectrum in the high-frequency bandwidth due to TDDH [31,32], the quality of the CNB speech signal is almost equivalent to that of the NB speech signal. However, the hidden vector may contain negative values despite that the magnitude spectrum accepts only nonnegative values.…”