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Computers are now found in every layer of the society, and information is being communicated and processed automatically on a large scale. So that daily communications of all kinds over the internet have become incredibly popular. Since the rise of the internet, one of the most important factors of information technology and communication has been the security of information. Thus many applications are Internet-based and in some cases, it is desired that the communication be made secret. In essence, the internet is an open channel and security problems such as interception, modification and others are very real. Several approaches have been proposed to make communication via the internet secure. One of these approaches is Cryptography, where the sender uses an encryption key to scramble the message, this scrambled message is transmitted through the insecure public channel, and the reconstruction of the original, unencrypted message is possible only if the receiver has the appropriate decryption key.

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Ghada Salim Mohamed is a lecturer in the University of Madenat Al-Elm, have Bachelors degree in computer science/information systems branch, Master degree in computer science/data security branch from the University of Technology/2008, published many researches in the field of cryptography.

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