الفهرس 
Chapter 1: IntroductionOnly 14 pages are availabe for public view
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Abstract
Since the early days of communication, diplomats and military commanders understood that it was necessary to provide some mechanism to protect the confidentiality of correspondence. And nowadays, network security is an important aspect of information sharing. The amount of data, transferred, is not a basic factor. The basic factor is, how much security, the channel provides while transmitting data. Attempts are made to remove various insecurities over internet. For this purpose, many technological implementations and security policies have been developed. Cryptography which is the art of secret writing and steganography which is the art of hidden writing are two of the most common techniques that used to achieve the required security and privacy for the information sharing.
In this work we will combine cryptography and steganography together to get a high level of security. First we will present a proposed triple Hill cipher algorithm as a cryptographic technique. The algorithm consists of three stages of Hill cipher. Each considered stage is a block cipher with a block length of 128 bits and key length of 256 bits. The message to be encrypted is processed by this block cipher three times. The keys are taken from random number generator. Each stage consists of eight rounds. Each round includes three operations; key and plaintext matrix multiplication, stir operation and XOR operation. Secondly we will present a proposed dynamic Least Significant Bit (LSB) image steganographic system that uses random number generator for selecting pixels from cover image randomly for the embedding process. Also it enables the user to select the number of LSBs needed for the embedding process with a dynamic behaviour in case of using two, three or four LSBs. The dynamic behaviour changes the embedding locations of LSBs according to the message needed to be hidden in order to make LSB technique more robust against statistical analysis.
The proposed techniques are coded in VHDL language and implemented using FPGA, which is flexible and reconfigurable integrated circuit. Implementing the proposed techniques on FPGA provides major benefits; namely high speed and high flexibility. FPGA implementation was accomplished on Space-Grade Virtex-4QV XQR4VSX55-10CF1140 device using Xilinx ISE Design Suite 13.2. The implementation results show fast designs with good area utilizations. The thesis includes seven chapters:-
Chapter 1: is the thesis introduction.
Chapter 2: is an introduction to cryptography.
Chapter 3: describes the proposed triple Hill cipher algorithm.
Chapter 4: is an introduction to steganography.
Chapter 5: describes the proposed dynamic LSB image steganographic system.
Chapter 6: gives an overview of FPGAs and discusses the simulation and the implementation results of the proposed systems.
Chapter 7: discusses the conclusions of this work and the recommendations for future work.