5.1-5.4 due on September 29

1. I had some difficulty with the key schedule. I didn't understand the whole process of how the key was selected from the original key. I also had some trouble following the decryption; especially the part about why the MC step was not used on the last round of the encryption process.

2. I found it interesting that the other four algorithm methods where secure and could have future possible use. What was the criteria for selection? Why was the Rijndael picked? I also found interesting how the S-box construction was carefully chosen to maximized bit diffusion and open so to avoid the mystery that was common with DES.