BLOCK ENCRYPTION ALGORITHM HAVING ROBUST SECURITY AGAINST DIFFERENTIAL CRYPTOGRAPHIC ANALYSIS, LINEAR CRYPTOGRAPHIC ANALYSIS, AND HIGHER DIFFERENTIAL CRYPTOGRAPHIC ANALYSIS

摘要

The present invention relates to a block encryption algorithm based on the prior Feistel type block encryption algorithm (or analogous to a DES algorithm). Usually, the security of the Feistel type block encryption algorithm depends on the structure of its tower function. More particularly, the present invention relates to the tower function structure of the Feistel type block encryption algorithm in the case where the tower input data block is divided into 8-bit blocks, and where the sub- divided blocks are provided, with the combined output data from the previous S box, in S box of 256 x 8, except for the first data input sub-block. The first data sub-block is supplied directly to the first box S. The total output data block is rotated by 8 bits, after these steps, and this result thus turned constitutes the output of the current lathe function. / P