Securing sockets with TLS/SSL

You have probably come across the discussion around secure web communication using Secure Socket Layer (SSL), or more precisely Transport Layer Security (TLS), which is adopted by many other high-level protocols. Let us see how we can wrap a plain sockets connection with SSL. Python has the built-in ssl module, which serves this purpose.

In this example, we would like to create a plain TCP socket and connect to an HTTPS enabled web server. Then, we can wrap that connection using SSL and check the various properties of the connection. For example, to check the identity of the remote web server, we can see if the hostname is same in the SSL certificate as we expect it to be. The following is an example of a secure socket-based client:

import socket
import ssl
from ssl import wrap_socket, CERT_NONE, PROTOCOL_TLSv1, SSLError
from ssl import SSLContext
from ssl import HAS_SNI

from pprint import pprint

TARGET_HOST = 'www.google.com'
SSL_PORT = 443
# Use the path...