The Block Cipher Rijndael Analysis And Refinements

Abstract

Our study of the block cipher Rijndael primarily focuses on two type of problems, 1. refinements and 2. cryptanalysis. Refinement implies suggesting an efficient implementation mechanism that reduces (a) the processing time and/or (b) memory space requirements of the microprocessor. The second problem of cryptanalysis focuses on the security aspect of the algorithm, that is, how fast the key can be guessed or secrecy of the algorithm can be compromised without the knowledge of actual key. In the present work we have focused on both the issues. We selected the most noted cryptographic algorithm Rijndael for our study. newlineThe Block Cipher Rijndael is a symmetric block cipher. It is designed to resist all known linear and differential cryptanalytic attacks as well as many other kind of attacks. It was proposed by Joan Daemen and Vincent Rijmen for the Advanced Encryption Standard (AES) and later selected as AES amongst the fifteen candidate submissions for AES to American National Institute of Stan-dards and Technology (NIST). On Nov.26, 2001, it was announced as Federal Information Processing Standard FIPS 197 by NIST. In the first problem on refinements we have remodel the block cipher Rijndael and propose an efficient byte-vector-matrix representation by convert-ing the four function structure for each round of Rijndael into a five variable exclusive OR (XOR) operation for each round without compromising in the ciphering properties of the Algorithm.