The article explains how to create a secure encryption system using a method called pseudorandom permutations. By using a pseudorandom function generator, researchers were able to construct a way to generate random, reversible permutations efficiently. This method is based on the design of the Data Encryption Standard and can protect against strong attacks on a cryptosystem. This means that any pseudorandom bit generator can be used to create a secure encryption system that can withstand chosen plaintext attacks.