الفهرس 
Chapter 1: IntroductionOnly 14 pages are availabe for public view
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Abstract
With the expansion in digital communication technologies and the rapid growth of network bandwidth, the Internet has turned out to be a much-used channel for transmitting many documents in digital form. This leads to the need for data security to ensure information safety during communication. Steganography is the technique that encompasses hiding secret information in an appropriate multimedia carrier, such as text, image, audio, video, and 3D (three dimensions) objects with invisible existence. Numerous 3D steganographic techniques have been developed by researchers and academics. 3D steganographic techniques are complex in nature but have better security and capacity compared to basic 2D (two dimensions) steganographic techniques. The 3D steganographic technique can generally be made in several ways: geometrical domain, topological domain, and representation domain steganography. Three techniques are presented in the geometrical domain based on hiding the binary representation of the secret message in the coordinates of the 3D objects, using several sequences (Gray code sequence, Recamán’s sequence, and Lucas sequence). The first objective of the thesis is the development of efficient and high capacity steganographic techniques for 3D objects using the geometrical characteristics of 3D objects. The first presented technique hides the secret message in the x- and y-coordinates of the 3D object vertices using the LSB (Least Significant Bit) technique and Gray code sequence. The second presented technique compresses the secret message to embed it in the LSBs of the x- and y-coordinates of the 3D object vertices utilizing the Gray-code sequence. It uses two secret keys to enhance privacy and security. The first key is used to rearrange the vertices of the 3D cover-object, while the second key generates the Gray code sequence. The third presented technique uses data compression or data encryption in the secret message before dividing it into three blocks and hiding each block in a specific vertex coordinate according to a specific sequence. The second objective of the thesis is the development of efficient and high security steganographic techniques for 3D objects using the geometrical characteristics of the 3D objects. The fourth technique utilizes the geometrical and topological characteristics of the 3D object to embed the binary representation of the secret message according to the Gray code sequence. These four techniques are implemented while preserving a high level of capacity and security, without causing any effects on the 3D object quality. Various performance metrics are used to evaluate these techniques, and remarkable numerical results are achieved in terms of capacity and security.