PC-RSA A cryptographic toolkit for MS-DOS

Abstract

In MS-DOS environments RSA encryption is very unusual. This is mainly due to throughput limitations of RSA-software. Still RSA is one of the most secure encryption methods and it is necessary to provide cryptographic methods that can be viewed as safe also for PC and MS-DOS environment. Increasing applications in the area of remote banking and in many other areas demand more and more for safe public key encryption. This paper presents a software package and its implementational aspects. The implementation bases on the assumption that no party can use the prime factors of the key. Algortihms for highly parallel execution are adopted and their efficiency on single instruction single data machines is discussed and found out to be adequate. This package is designed to be a compact module without large precomputed arrays. It exhibits about 850 bit/sec on a 33MHz 386 PC and over 400 bit/sec cyphering rate on a Toshiba 5200 Laptop with a 512 bit key.