الفهرس 
Cryptography
DES AND ELLIPTIC CURVESOnly 14 pages are availabe for public view
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Abstract
Recently, digital data communications are the most indispensable part of our life. Everything around us today is done using either the Internet or the intranet networks. The transferred data through these networks may have different levels of secrecy or privacy that could be compromised. Consequently, this entails a kind of protective measures to be taken to ensure the data’s security against any threat. Information security is the involved field of study that is responsible for learn- ing how to defend the transferred data from an unauthorized access. As a science, it categorizes the data security requirements to different services. This thesis con- cerns with the data confidentiality service, which is needed for retaining the trans- ferred data unrevealed to any unauthorized user. Cryptography is the employed
security mechanism to accomplish the task of data confidentiality.
Data Encryption Standard (DES) was an encryption algorithm that was used to conceal the transferred data content to ensure its privacy. It was introduced in 1977 and was the most prevalent algorithm at that time. Although DES showed a great immunity to different types of the analytical attacks, it was very weak to withstand the brute-force attack. Accordingly, DES was withdrawn in 1999 and was acknowledged as an insecure algorithm. However, many existing algorithms still depend mostly on the design of DES especially its successor, the Triple DES. This thesis addresses the main issue of the DES’s algorithm, which is its vul- nerability to the brute-force attack. Two approaches are introduced that overcome this issue entirely and bring the withdrawn DES to live. The first approach em- ploys the art of the Elliptic Curve Cryptography (ECC) to fortify the classical DES
algorithm. On the other hand, the second approach employs both the ECC and the chaotic logistic map to achieve the same goal. This thesis demonstrates the soft- ware implementation for both approaches. It exhibits the designs and the adopted algorithms and techniques to realize each of them.
The presented approaches are applied in establishing a communication session between two entities to transfer securely any kind of the multimedia files (Image, Audio, Video). Detailed experimental analyses are done to assess the robustness of the two approaches against different kinds of attacks. The experimental analy- ses show that the brute-force attack on either of the two approaches is extremely infeasible. In addition, the two approaches are very immune to the different kinds of the analytical attacks.