cert_time_to_seconds function of ssl module in python

Function Name:

cert_time_to_seconds

Function Signature:

cert_time_to_seconds(cert_time)

Parameters:

cert_time – The time string in "%b %d %H:%M:%S %Y %Z" strptime format.

Return Value:

The number of seconds elapsed since Epoch corresponding the time specified in the parameter cert_time.

Overview:

When two hosts communicate through network I/O via stream based sockets, a host can authenticate the identity of the other host involved in the communication through the digital certificate of the other host.
A Certificate Authority issues a digital certificate.
Digital certificates issued by a Certificate Authority have validity for a specific time period.
Validity of a digital certificate starts after the time specified by the field “notBefore” and ends after the elapse of the time specified by the field “notAfter”.
The method ssl.cert_time_to_seconds(cert_time) converts the string format of the time given in the “notBefore” and “notAfter" fields to number of seconds since Epoch. The time returned is in GMT - Greenwich Mean Time.

Example:

import socket

import ssl

import platform

import os

# Create an SSL context

securityContext = ssl.SSLContext();

securityContext.verify_mode = ssl.CERT_REQUIRED;

securityContext.check_hostname = True;

securityContext.load_default_certs();

# Check for OS X platform

if platform.system().lower() == 'darwin':

import certifi

securityContext.load_verify_locations(

cafile=os.path.relpath(certifi.where()),

capath=None,

cadata=None);

# Socket properties

socket_address_family = socket.AF_INET;

socket_type = socket.SOCK_STREAM;

# Create a streaming socket

connection = socket.socket(socket_address_family, socket_type);

# Create a secure socket

secure_connection = securityContext.wrap_socket(connection,

server_hostname="example.org");

# Connect to host

secure_connection.connect(("example.org",443));

# Get the certificate from the host

cert = secure_connection.getpeercert(binary_form=False);

# Get the validity related attributes

print("Certificate validity:");

print("Not before:%s"%cert['notBefore']);

# Convert the time string into timestamp

print("As timestamp:%d"%ssl.cert_time_to_seconds(cert['notBefore']));

print("Not after:%s"%cert['notAfter']);

# Convert the time string into timestamp

print("As timestamp:%d"%ssl.cert_time_to_seconds(cert['notAfter']));

Output:

Certificate validity:

Not before:Nov 28 00:00:00 2018 GMT

As timestamp:1543363200

Not after:Dec 2 12:00:00 2020 GMT

As timestamp:1606910400

Cert_time_to_seconds function of ssl module in python