Cryptography, defined as the science and study of secret writing, concerns the ways in which communications and data can be encoded to prevent disclosure of their contents through eavesdropping or message interception, using codes, ciphers and other methods, so that only intended people can see the real message. In this paper, we propose the design and implementation of a new symmetric key algorithm. The algorithm encrypts the plaintext file by using the password of the file as the key. The plaintext and key are split in equal numbers and shift cipher is applied to each block of the plaintext. This new algorithm can be considered as a hybrid approach to its precursors.

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Symmetric cryptosystem split-plaintext-key pair