4.1-4.4 due September 21st

The simplified des type algorithm is really interesting! It takes the bit system we've been working with, but in a different way. It looks simple enough, but must be secure to have worked for so long. 

I had difficultly understanding the s boxes and how to come up with them. I was confused on how they are used. The process for encrypting and decrypting the sea permutations in section 4.4 look tedious. I don't understand how all he boxes and crossing. Arrows work.