This paper describes a very fast software implementation of the Federa
l Data Encryption Standard (DES) for the 8086 processor family. The c
omplex instruction set of this processor family is exploited to implem
ent the low-level bit manipulation of the DES in an efficient manner.
A 386/33 MHz PC is capable of data rates of over 200 kpbs, including t
ime taken to read from and write to hard disk.