الفهرس 
CHAPTER 1: INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Steganography is the art or science used in a secret communication. It aims to conceal the existence of a secret message without any suspicion in the existence of this message. This secret message is amalgamated inside another public message which is any cover media such as text, audio, image and video. It may be any type of a digital media and there is no relationship between the two messages where the cover is just to safeguard the secret message from any infringement of privacy.
In this thesis, the audio steganography is used that is based on amalgamating the secret message into an audio file. This is because the audio files have high capacity and also they spread, availability and popularity in the human society. However, the human auditory system (HAS) is more sensitive than the human visual system (HVS) and this needs more challenging and more accuracy in the process of concealment.
This thesis proposes two audio steganography methods. The first method is based on the least significant bit (LSB) technique with some modifications using lifting wavelet transform (LWT) technique, and three random keys. These random keys are used to increase the robustness of the LSB technique. The second proposed method is based on a hybrid between two techniques of audio steganography. These techniques are LSB technique and modifications of phase coding technique. This hybrid is to improve the performance of the phase coding technique where the performance of it is very low and to increase the robustness of the LSB technique.
These proposed methods are tested on different types of the secret message such as text, audio, gray image and color image. These methods
are tested using the audio steganography evaluation tests and also are compared with some known methods. from the results of the signal to noise ratio (SNR) and the comparison with the previous methods, we find that the result of the first method is better than other methods and also the result of the second method is better than using LSB and phase coding technique individually.