TLS protocol is a successor of SSL or Secure Socket Layer. This ensures that the communication between the client and the server is secure. This is done by sending the message in an encrypted format so that unauthorized people cannot see the message. It is not difficult to use TLS with smtplib. After you create an SMTP session object, you need to call the starttls() method. Before sending an e-mail, you need to login to the server by using the SMTP server credentials.

Here is an example for the second e-mail client:

#!/usr/bin/env python3
# Listing 2
import getpass
import smtplib

from email.mime.image import MIMEImage
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText

SMTP_SERVER = 'smtp.gmail.com'
SMTP_PORT = 587 # ssl port 465, tls port 587

def send_email(sender, recipient):
    """ Send email message """
    msg = MIMEMultipart()
    msg['To'] = recipient
    msg['From'] = sender
    msg['Subject'] = input('Enter your...