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A Description of the MISTY1 Encryption Algorithm (RFC2994)

IP.com Disclosure Number: IPCOM000005188D
Original Publication Date: 2000-Nov-01
Included in the Prior Art Database: 2005-May-17
Document File: 11 page(s) / 18K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

H. Ohta: AUTHOR [+2]

Abstract

This document describes a secret-key cryptosystem MISTY1, which is block cipher with a 128-bit key, a 64-bit block and a variable number of rounds. It documents the algorithm description including key scheduling part and data randomizing part.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 15% of the total text.

Network Working Group                                            H. Ohta
Request for Comments: 2994                                     M. Matsui
Category: Informational                  Mitsubishi Electric Corporation
                                                           November 2000


            A Description of the MISTY1 Encryption Algorithm

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2000).  All Rights Reserved.

Abstract

   This document describes a secret-key cryptosystem MISTY1, which is
   block cipher with a 128-bit key, a 64-bit block and a variable number
   of rounds.  It documents the algorithm description including key
   scheduling part and data randomizing part.

1. Introduction

   This document describes a secret-key cryptosystem MISTY1, which is
   block cipher with a 128-bit key, a 64-bit block and a variable number
   of rounds.  It is designed on the basis of the theory of provable
   security against differential and linear cryptanalysis, and moreover
   it realizes high-speed encryption on hardware platforms as well as on
   software environments.  As the result of weighing strength and speed,
   8-rounds of MISTY1 is recommended and used in most cases.

   Our implementation shows that MISTY1 with eight rounds can encrypt a
   data stream in CBC mode at a speed of 57Mbps and 40Mbps on Pentium
   II/266MHz and PA-7200/120MHz, respectively.  For its hardware
   performance, we have produced a prototype LSI by a process of 0.8-
   micron CMOS gate-array and confirmed a speed of 512Mbps.

2. Algorithm Description

   Algorithm [1] could be divided into two parts, namely "key scheduling
   part" and "data randomizing part".  Key scheduling part takes a 128-
   bit input key and produces a 128-bit expanded key.  Data randomizing

Ohta & Matsui                Informational                      [Page 1]
RFC 2994                         MISTY1                    November 2000


   part takes a 64-bit input data and mixes it, namely encryption.  If
   data randomizing part is processed in reverse order, mixed data is
   transformed to input data, namely decryption.

2.1 Terminology

   Some operators are used in this document to describe the algorithm.
   The operator `+' indicates two's complement addition.  The operator
   `*' indicates multiplication.  The operator `/' yields the quotient,
   and the operator `%' yields the remainder from the division.  The
   operator `&' indicates bitwise AND operation.  The operator `|'
...