Frequently Asked Questions

How can I extract a public / private key from a x509 certificate?

The load_pem_x509_certificate() function from cryptography can be used to extract the public or private keys from a x509 certificate in PEM format.

from cryptography.x509 import load_pem_x509_certificate
from cryptography.hazmat.backends import default_backend

cert_str = "-----BEGIN CERTIFICATE-----MIIDETCCAfm..."
cert_obj = load_pem_x509_certificate(cert_str, default_backend())
public_key = cert_obj.public_key()
private_key = cert_obj.private_key()

I’m using Google App Engine and can’t install cryptography, what can I do?

Some platforms like Google App Engine don’t allow you to install libraries that require C extensions to be built (like cryptography). If you’re deploying to one of those environments, you should check out Legacy Dependencies