Example of how to do certificate fingerprinting with cryptography

fingerprinting.py

# Needed for boring connection logic
import ssl
import socket

# Needed for the cert work
from binascii import hexlify

from cryptography import x509
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import hashes

HOSTNAME = 'http2bin.org'

# Boring connection logic
s = socket.socket()
c = ssl.create_default_context()
s = c.wrap_socket(s, server_hostname=HOSTNAME)
s.connect((HOSTNAME, 443))

# The meat of the work.
der = s.getpeercert(binary_form=True)
cert = x509.load_der_x509_certificate(der, default_backend())
print hexlify(cert.fingerprint(hashes.SHA256()))