SUBSTITUTION- SHIFTING- FOLDING CIPHER ALGORITHM WITH DYNAMIC SYMMETRIC ENCRYPTION KEY

Abstract

In modern security models, cryptography plays a fundamental role in protecting data integrity and confidentiality in information systems. However, cryptography itself is subject to cryptanalysis attacks. To reduce the cryptanalysis attack risk Encryption/Decryption application is presents in this paper. Encryption involves several processes which is implemented in reverse order in decryption , this method ensure make hard to intruder to guess the true sequences to solve encrypted message .The algorithm involves substitution ,shifting , and folding , these process will be implemented in reverse order in decryption causes a confusion for intruder who does not know the right sequence of the algorithm. Encryption key is dynamic and generated independently for each text depending on the length of the message to be encrypted and Practical because there is no need to exchange encryption keys between sender and receiver cause the receiver knowing how to generate them. As a result, the proposed system diffusion is accomplished by using folding algorithm which rearrange the character of the message after encryption in such away that the frequency of characters will not be appear clearly. Confusion also is performed by using several keys for the same message each key should consist of 2 digits then each digit is used alone with single letter of plaintext then the remaining encryption keys used sequentially according to their generating sequence. For a small amount of data this algorithm will work very smoothly and quickly