This section provides a quick introduction to SSL client authentication, which is needed if the SSL server wants the client's identity to be authenticated.
As I mentioned earlier in this book, the SSL handshake process follows these steps:
Two identity authentications may happen during this process:
1. Server Authentication - Server program must have access to the server's
"full" certificate, which contains the server's identity, public key and
private key. During handshake process, the server will extract the server's
"public" certificate and send it to the client. On the client side,
the client program must be able to authenticate the server's identity by
validating the server's "public" certificate.
One way to identify the server's identity is to install server's "public"
certificate to client program as a trusted certificate.
Server authentication seems to be always required.
2. Client Authentication - This is the 100% mirror process of server authentication.
However, client authentication is optional for SSL communication.