الفهرس 
Chapter 1 IntroductionOnly 14 pages are availabe for public view
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Abstract
With the huge advancements in information technology and data communication fields, steganography and cryptography become a major information security concerns when building a data hiding system and hence gained wide importance in the researcher’s studies. DNA based steganography depends on exploiting the DNA nucleotides with their distinctive features as confidential information carriers which enhance the data hiding process massively, but in spite of that a lot of security-related issues and drawbacks emerged and must be addressed like maximizing the sequence embedding Capacity, minimizing its modification rate, and ensuring the system robustness, and visual imperceptibility for the hidden data.In an attempt to tackle these problems and treat these issues, a special kind of hiding mechanism is adopted in this thesis using DNA sequences that depend on iterating a 3D logistic chaotic map to generate three pseudo-random key sequences. The proposed approach encodes the secret message in a binary form together with two of the random keys into DNA sequences. It ensures extra DNA encryption, by carrying out some DNA sequence operations. Besides, it creates a fake sequence by embedding the generated sequence into another public reference sequence. The fake sequence is then hidden back into the cover image to achieve a double layer of data hiding. The proposed data hiding system is considered as a double layer of security as; the secret data encrypted using the DNA before hidden in another reference sequence to produce the fake sequence, dual hiding because; the fake sequence is then hidden back into the cover image before sends it to the recipient, not pure data hiding system due to; the secret key generated by the 3D chaotic map parameters, and with adequate visual imperceptibility. Compared to similar approaches, experiments verifies that our approach satisfies the robustness of data hiding under reasonable average embedding capacity of 0.83 ,blindness, zero-payload, low modification rate of 5.16% (on average), zero-expansion rate, and high probability cracking.