Simplified DES (SDES) is a "toy" symmetric encryption algorithm created by Ed Schaefer. It is meant for instructional purposes as a companion to Data Encryption Standard (DES). The idea is to impart a feeling for the real DES without the large amount of computation that is required of industrial-strength DES. Still, computing SDES can be error-prone and tedious. This calculator will do the necessary computations, while exposing each and every intermediate result on request. With this tool, a student can work out examples by hand (which is preferable in this case) while checking the intermediate steps so that errors do not propogate.
A group of students might also use this calculator for a distributed brute-force attack on SDES when given pairs of plaintext and ciphertext all generated with the same key. The 10-bit key size might allow for reasonable size partitions if each student is asked to check all possible keys with the first few bits fixed.
The interested user should consult one of the references below for a complete treatment of SDES. I've relied mostly on Stallings during development.
References:
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
GNU Public License Information
Source and class files are available here for download as a JAR file.
Rob Beezer, BEEZER(at)UPS(dot)EDU, Updated: May 22, 2003