Chaos and NDFT-based spread spectrum concealing of fingerprint-biometric data into audio signals

In this paper, we propose a chaos and NDFT-based spread spectrum technique to conceal fingerprint-biometrics templates into audio signals. Fingerprint templates are encrypted by chaotic encryption, encoded by the BCH codes, modulated by chaotic parameter modulation (CPM), and then hid into the chaotically selected random sampling points of the host speech signal by a novel non-uniform discrete Fourier transform (NDFT)-based data hiding method. The template extraction process is completely blind and does not require original speech signal, thus the extraction depends on the secret key. Experimental and simulation results show that the proposed scheme is robust against common signal processing attacks, secure by secret keys, efficient in performance, and accomplishes perceptual transparency by exploiting the masking effects of human auditory system (HAS).