Date Added: Dec 2011
A session based symmetric key cryptographic system has been proposed in this paper and it is termed as Bit Orientation Technique (BOT). This technique is more fast, suitable and secure for encryption of large files. BOT 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 diagonally upward from left to right into a square matrix of suitable order. Bits are taken row-wise 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 BOT.