Run a OCSP responder

OCSP, or the Online Certificate Status Protocol provides a second method (besides CRLs) for a client to find out if a certificate has been revoked.

Configure OCSP with django-ca

If you have (correctly) configured a CA_DEFAULT_HOSTNAME and setup the web server under that URL, you do not have to configure anything to run an OCSP responder.

OCSP with docker compose

If you use the docker compose, the setup already provides OCSP services for all issued certificates.

OCSP with other setups

If your setup does not run with a Celery task broker, you need to automatically regenerate the OCSP certificates e.g. once a day. To regenerate them, you only need to keys/certificates using a manage.py command:

$ python manage.py regenerate_ocsp_keys

Note that you need to pass a password if you have a CA where the private key is encrypted. If you have only some CAs with a password, or you use different passwords, you’ll have to generate keys individually:

$ python manage.py list_cas
11:22:33 - CA with password foo
44:55:66 - CA with password bar
$ python manage.py regenerate_ocsp_keys --password foo 11:22:33
$ python manage.py regenerate_ocsp_keys --password bar 44:55:66

Manual setup

django-ca provides the generic view OCSPView for an OCSP service for your certificate authorities. This allows for special OCSP services with “unusual” settings, but is usually not needed, the default setup should do just fine.

The setup involves:

  1. Creating a responder certificate

  2. Configure generic views

  3. Add a OCSP URL to the new certificate

Create an OCSP responder certificate

To run an OCSP responder, you first need a certificate with some special properties. Luckily, django-ca has a profile predefined for you:

$ openssl genrsa -out ocsp.key 4096
$ openssl req -new -key ocsp.key -out ocsp.csr -utf8 -batch
$ python manage.py sign_cert --csr=ocsp.csr --out=ocsp.pem \
>     --subject-format=rfc4514 --subject CN=ocsp.example.com --ocsp

Warning

The CommonName in the certificates subject must match the domain where you host your django-ca installation.

Configure generic views

The final step in configuring an OCSP responder for the CA is configuring the HTTP endpoint. If you’ve installed django-ca as a full project or include django_ca.urls in your root URL configuration, configure the CA_OCSP_URLS setting. It’s a dictionary configuring instances of OCSPView. Keys become part of the URL pattern, the value is a dictionary for the arguments of the view. For example:

CA_OCSP_URLS = {
    'root-ca': {
        'responder_key': '/usr/share/django-ca/ocsp.key',
        'responder_cert': '/usr/share/django-ca/ocsp.pem',

        # optional: The name or serial of the CA. By default, the dictionary key ("Root CA" in
        #           this example is assumed to be the CA name or serial.
        #'ca': '34:D6:02:B5:B8:27:4F:51:9A:16:0C:B8:56:B7:79:3F',

        # optional: How long OCSP responses are valid
        #'expires': 3600,
    },

    # This URL can be added to any intermediate CA using the --ca-ocsp-url parameter
    'intermediate-ca': {
        # Dictionary key is not the name of the root CA, so we pass a serial instead:
        'ca': '34:D6:02:B5:B8:27:4F:51:9A:16:0C:B8:56:B7:79:3F',
        'responder_key': '/usr/share/django-ca/ocsp.key',
        'responder_cert': '/usr/share/django-ca/ocsp.pem',

        # optional: This URL serves OCSP responses for Child CAs, not signed enduser certs:
        #'ca_ocsp': True,
    }
}

This would mean that your OCSP responder would be located at /django_ca/ocsp/root-ca/ at whatever domain you have configured your WSGI daemon. If you’re using your own URL configuration, pass the same parameters to the as_view() method. Please see the the class documentation for possible options:

Add OCSP URL to new certificates

To include the URL to an OCSP service to newly issued certificates (you cannot add it to already issued certificates, obviously), either set it in the admin interface or via the command line:

$ python manage.py list_cas
34:D6:02:B5:B8:27:4F:51:9A:16:0C:B8:56:B7:79:3F - Root CA
$ python manage.py edit_ca --ocsp-url=http://ocsp.example.com/django_ca/ocsp/root-ca/ \
>     34:D6:02:B5:B8:27:4F:51:9A:16:0C:B8:56:B7:79:3F