In cryptography, hash functions have very important effects when it's used in the message integrity, digital time stamping, and digital signature. Hash functions compute hash value by a set of logical (primitive) operations that perform on a (32) bit words for authentication. Authentication process becomes very important especially manipulated message undetected that can have disastrous effects in Network Management and E-Commerce. In this paper, a proposal for new hash function based on MD5 is developed. The length of message digest is 224-bit through (4) rounds that each round has a pair of (16) steps. The final number of steps is (128) that make stronger function against collision attests and more secure than MD5.

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The main aim of this article is to provide a short review of the most important argumentation frameworks (AFs) systems being used. This paper presents the overall thought of unique argumentation, featuring the work way of these theoretical systems in the argumentation interaction and surveys the first Dung structures. It introduces how these systems give acceptable arguments by focused on the argumentation frameworks structures and how to deal with the arguments and the basic rules to give the result. Finally, it surveys the idea of theoretical rationalistic structures, quite possibly the broadest frameworks for dynamic argumentation, and gives a short description of several argumentation frameworks that are more famous.

There are two very important characteristics in the block cipher, the amount of time for encryption process and key complexity which caused increasing the complexity of encryption process. This research aims to enhance the key generation of Advanced Encryption Standard (AES) algorithm with high efficiency. The proposed enhancement method architecture based on modifying cipher feedback (MCFB) mode which produce key block from each key generation step in addition to represent current output that is repeated lyre used as input to produce next key block. In the block cipher encryption step, two processes are implemented: Substitution bytes process and Shift rows process. This proposed method improves the performance, efficiency, and speed of the encryption algorithm.