The next protocol I'm going to talk about is called TLS,
which stands for Transport Layer Security.
It's also sometimes referred to by it's old name, which was SSL, which was Secure Sockets Layer.
This is the protocol that was invented by Netscape in 1995 with the goal of enabling clients,
meaning web browsers and web servers, to be able to communicate securely.
This is really the essential thing for creating ecommerce.
It's the protocol that, among other things, allows people to send credit card numbers
over the Internet as well as other personal information
with some confidence that it's going only to the intended destination.
It consists of two main parts.
The first is the Handshake Protocol, and that's used to authenticate a server to a client.
It can be in both directions. It can also be used to authenticate clients to servers.
The way it's used on the web, this rarely happens.
This would require clients to have public keys that would be known to the servers.
The other outcomes of the Handshake Protocol
are agreement on the cryptographic protocols to use.
TLS is a very complex protocol that allows many different
encryption algorithms to be used for different parts of it.
Part of the handshake is to agree on which one is to use.
And the final thing is the essential outcome for communication
to establish a shared session key--a key shared between the server and the client.
The second part of the TLS protocol is the TLS record protocol.
That's done after the handshake to enable secured communication
between the client and the server
using the session key that they established from the handshake.
The question for this quiz is which one of these two protocols
is likely to involve asymmetric cryptography?
I haven't described the protocols yet, but based on what they do,
you should be able to figure out which one is likely to use asymmetric cryptography.
