5.1-5.4, due on September 29

1. (Difficult) The most difficult part was probably in section 5.3 where the book discusses different ways of looking at decryption.  I didn't really understand that well in CS465 either.  I also don't understand the advantage of making decryption looking more like encryption: since it's not exactly the same, it seems the implementations for encryption and decryption will have to be different any how?  Perhaps it's to reduce implementation effort?
2. (Reflective) I appreciated the simple explanation of why decryption is slower than encryption (assuming that the more complex matrix does take longer to multiply).
   I thought the last sentence of the reading was interesting: "Of course, the number of rounds could easily be increased if needed."  I guess this is a matter of perspective.  Without being an expert cryptographer, I can see how theoretically it may not be difficult to add more rounds.  Also, as a programmer, I think it would be a pretty small change in an implementation of the AES algorithm itself.  But, I think with how widely used AES appears to be, that it might be quite difficult to change the number of rounds in practice.  I think we learned (or it makes sense) that the changes wouldn't be backwards compatible.  It seems like getting people on the new system, while not breaking backwards compatibility, if possible, would be a significant effort.