ABSTRACT

In this paper, a session based symmetric key cryptographic system has been proposed and it is termed as Bit Shuffle Technique (BST). This proposed technique is very fast, suitable and secure for encryption of large files. BST consider the plain text (i.e. the input file) as binary string with finite no. of bits. The input binary string is broken down into manageable-sized blocks to fit row-wise from left to right into a square matrix of suitable order. Bits are taken diagonally upward from the square matrix to form the encrypted binary string and from this string cipher text is formed. Combination of values of block length and no. of blocks of a session generates the session key for BST. For decryption the cipher text is considered as binary string. Using the session key information, this binary string is broken down into manageable-sized blocks to fit diagonally upward from left to right into a square matrix of suitable order. Bits are taken row-wise from left to right from the square matrix to form the decrypted binary string and from this string plain text is formed. A comparison of BST with existing and industrially accepted TDES and AES has been done.