Study on Security Enhancement of 64-Bit NFSR-based Block Cipher Systems with Ring Structure

摘要

In the modern information society, security techniques (cryptography, authentication) are very important when we exchange secret/private information. In our laboratory, block cipher systems using nonlinear feedback shift register (NFSR) have been proposed and their performance has been evaluated. The NFSR is one of pseudorandom number generators, which is composed of D flip-flops and a combinational logic circuit. In this paper, we improve the NFSR-based 64-bit block cipher systems with ring structure for security enhancement.