Chapter 7: Cryptography - Public Key Infrastructure

I have found a website that explains PKI in a way that I understand a little better than the way the book puts it. Here is the link.

http://searchsecurity.techtarget.com/definition/PKI

Also, here is a diagram from the website that is helpful in describing whose key to use and what type of key to use.

To do this	Use whose	Kind of key
Send an encrypted message	Use the receiver's	Public key
Send an encrypted signature	Use the sender's	Private key
Decrypt an encrypted message	Use the receiver's	Private key
Decrypt an encrypted signature (and authenticate the sender)	Use the sender's	Public key

Below is another diagram that shows how PKI works in digital communication from http://www.asu.edu/ecure/2002/dollar/