Animation engine by Eric Fikus, content
and animation code modifications by Jedidiah
For a good background reading on S-DES and diffusion see Chapter 3 of Cryptography and Network Security: Principles and Practice by William Stallings
This was created as part of the Cryptography Module of NSF Award No. 0113627: "Increasing Security Expertise in Aviation-oriented Computing Education: A Modular Approach", at Embry-Riddle Aeronautical University in Prescott, Arizona.