PKI for busy people
The part about signatures is not really correct.It says:
"    To sign a message, encrypt it with the private key
    To verify a signature, decrypt it with the public key and make sure it matches the message"This is only half true for one algorithm: RSA. But even there it's only true for something called "Textbook RSA", which is an insecure variant of RSA nobody should be using. It's not true for any real algorithm.I'm really not a fan of such sloppy "I want to explain it easy" crypto introductions that are simply not correct.(Also found it odd that he uses "Verisign" as an example for a CA. Verisign has been bought by Symantec and Symantec was distrusted by browsers recently, so it's as dead as it can be.)