DESvisual: a visualization tool for the DES cipher

Abstract

This paper describes a visualization tool DESvisual that helps students understand and instructors teach the building blocks of symmetric encryption. In particular, the tool depicts the primitive operations required to perform the initial permutation and one Feistel round of DES using either an eight or 16 bit input. A student can trace through an encryption performed by the tool, or can be guided through an encryption or decryption, computing the output of each operation herself. This helps students to understand the primitive operations, how these operations are composed into the DES algorithm, and how functions and their composition are depicted and documented. Furthermore, the opportunity for self-study provides an instructor greater flexibility in selecting a lecture pace over this detail-filled material. Security concerns impact an ever increasing number of the applications that computer scientists design and develop. Many security problems are solved through use of cryptography. Unfortunately, computer science students commonly have difficulty with the sophisticated mathematics used in cryptographic algorithms.