Development of an Audio Steganography System Using Discrete Cosine Transform and Spread Spectrum Techniques

Abstract

In today’s electronic society, security of information is an issue of major concern especially in the communication domain. Indeed, there is a very serious need for schemes that guarantee security of information exchanged between entities, over public networks. Several techniques such as cryptography and/or steganography have been proposed in existing literature. Audio steganography has certain advantages over conventional steganography. Existing audio steganography systems suffer from limitations that includes, their inability to embed information in multiple audio file formats, high distortion rate and low level of robustness of their resultant stego-files. To overcome these limitations, this current research focused on the development of an efficient and robust audio steganography system for the security of information whether in store or on transit across the Internet. This is achieved by first encrypting a given secret information, compressing the resultant cipher-text, then embedding the compressed file in a suitable cover (audio file) using frequency hopping spread spectrum technique, to yield as output, an audio stego file which is not distinguishable from the original audio cover file. To allow for the embedding of the secret compressed file, the selected audio cover file is first broken into frames using one dimensional Discrete Cosine Transform (DCT). Results of performance evaluation of this developed system shows that it has very low level of distortion as revealed by the Signal to Noise Ratio (SNR). The compression ratio obtained is also equal to one (1), which shows that the cover audio file is identical to the resultant stego-file.