  On the rise of the Internet, digital data became openly public which has
driven IT industries to pay special consideration to data confidentiality. At
present, two main techniques are being used: Cryptography and Steganography. In
effect, cryptography garbles a secret message turning it into a meaningless
form; while, steganography hides the very existence of the message by embedding
it into an intermediate such as a computer file. In fact, in audio
steganography, this computer file is a digital audio file in which secret data
are concealed, predominantly, into the bits that make up its audio samples.
This paper proposes a novel steganography technique for hiding digital data
into uncompressed audio files using a randomized algorithm and a context-free
grammar coupled with a lexicon of words. Furthermore, the proposed technique
uses two intermediates to transmit the secret data between communicating
parties: The first intermediate is an audio file whose audio samples, which are
selected randomly, are used to conceal the secret data; whereas, the second
intermediate is a grammatically correct English text that is generated at
runtime using a context-free grammar and it encodes the location of the random
audio samples in the audio file. The proposed technique is stealthy and
irrecoverable in a sense that it is difficult for unauthorized third parties to
detect the presence of and recover the secret data. Experiments conducted
showed how the covering and the uncovering processes of the proposed technique
work. As future work, a semantic analyzer is to be developed so as to make the
intermediate text not only grammatically correct but also semantically
plausible.
