Analysis of Simplified DES Algorithms

The Data Encryption Standard (DES) is no longer secure because of its small key size. One way to augment the keyspace is to perform multiple encryptions with DES. This paper examines the cryptographic consequences of multiple encryptions with DES through two simplified DES algorithms. Both simplified algorithms, under multiple encryptions, generate the alternating group of permutations on the message space. Moreover, equivalent keys and key pairs are rare in both cases. These facts support past work that has shown that performing multiple encryptions with DES adds keyspace by demonstrating that the increase in keyspace is significant.