Block Cipher Explanation

Jinuyr

I was wondering if the community can help explain a concept for me since the Official CISSP CBK book and Shon Harris AIO is confusing the heck out of me. I tried looking it up online (Wikipedia, etc...) and that was more confusing.

Page 692 on Shon Harris AIO
Page 347 on Official CISSP CBK

Anyone have a relatively simple to understand explanation of Block Ciphers and the S-box? More specifically when the Substitute Bytes happens.

JDMurray

Which edition of both books?


A Stick Figure Guide to the Advanced Encryption Standard (AES)

Jinuyr

2nd Edition Official and 5th Edition AIO

JDMurray

For the CISSP, you'll only need to know the purpose of the S-boxes and not exactly how they do what they do. I think of them as algorithmic machines that process data in different ways based on the key and plain-text data patterns fed into them. Also understand about confusion, diffusion, and transposition. The comic in the link in my previous post covers that pretty well.

Jinuyr

Oh thank goodness! I was bashing my head against a wall trying to memorize all those figures and pictures.