`django_ca.models` - django-ca models¶

django-ca uses three classes, called “models” in Django terminology, to store everything in the database. They are the core classes for this project, if you want to use this project programatically, you’ll have to use these classes:

CertificateAuthority is used to store certificate authorities.
Certificate is used to store certificates.
Finally, Watcher stores email addresses for who should be notified if certificates expire.

Note that both CertificateAuthority and Certificate inherit from X509CertMixin, which provides many common convenience methods.

CertificateAuthority¶

class django_ca.models.CertificateAuthority(id, created, valid_from, expires, pub, cn, serial, revoked, revoked_date, revoked_reason, name, enabled, parent, private_key_path, crl_url, issuer_url, ocsp_url, issuer_alt_name)[source]¶

allows_intermediate_ca¶: Wether this CA allows creating intermediate CAs.

bundle¶

A list of any parent CAs, including this CA.

The list is ordered so the Root CA will be the first.

get_authority_key_identifier()[source]¶: Return the AuthorityKeyIdentifier extension used in certificates signed by this CA.

max_pathlen¶

The maximum pathlen for any intermediate CAs signed by this CA.

This value is either None, if this and all parent CAs don’t have a pathlen attribute, or an int if any parent CA has the attribute.

name¶: Human-readable name of the CA, only used for displaying the CA.

pathlen¶: The pathlen attribute of the BasicConstraints extension (either an int or None).

Creating CAs¶

Use CertificateAuthority.objects.init() to create new certificate authorities. The method has many options but is designed to provide defaults that work in most cases:

>>> from django_ca.models import CertificateAuthority
>>> ca = CertificateAuthority.objects.init(
...   name='ca', subject='/CN=ca.example.com',
...   pathlen=1  # so we can create one level of intermediate CAs
... )
>>> ca
<CertificateAuthority: ca>

This CA will contain all properties and X509 extensions to be a fully functioning CA. To create an intermediate CA, simply pass the parent:

>>> child = CertificateAuthority.objects.init(
...   name='child', subject='/CN=child.example.com',
...   parent=ca)
>>> child.parent
<CertificateAuthority: ca>
>>> ca.children.all()
<CertificateAuthorityQuerySet [<CertificateAuthority: child>]>

Or to create a CA with all extensions that live CAs have, you can pass many more parameters:

>>> full = CertificateAuthority.objects.init(
...   name='full', subject='/CN=full.example.com',
...   parent=ca,  # some extensions are only valid for intermediate CAs
...   issuer_url='http://full.example.com/full.der',
...   # this CA can only sign for *.com domains:
...   name_constraints=(['DNS:.com'], []),
...
...   # CRL/OCSP URLs for signed certificates. These can be changed later:
...   crl_url=['http://full.example.com/full.crl', ],
...   ocsp_url='http://full.example.com/ocsp',
...
...   # CRL/OCSP/Issuer URLs for the CA. These are only meaningful for
...   # intermediate CAs:
...   ca_crl_url=['http://parent.example.com/parent.crl', ],
...   ca_ocsp_url='http://parent.example.com/ocsp',
...   ca_issuer_url='http://parent.example.com/parent.crt'
... )

There are some more parameters to configure how the CA will be signed:

>>> CertificateAuthority.objects.init(
...   name='props', subject='/CN=child.example.com',
...   algorithm='SHA256',  # sha512 would be the default
...   pathlen=3,  # three levels of intermediate CAs allowed,
...   password=b'foobar',  # encrypt private key with this password
...   key_size=4096,  # key size for RSA keys - unused in this example
...   key_type='ECC',  # create an ECC private key
...   ecc_curve='SECP256R1'
... )
<CertificateAuthority: props>

Here are all parameters for creating CAs:

CertificateAuthorityManager.init(name, subject, expires=None, algorithm=None, parent=None, pathlen=None, issuer_url=None, issuer_alt_name='', crl_url=None, ocsp_url=None, ca_issuer_url=None, ca_crl_url=None, ca_ocsp_url=None, name_constraints=None, password=None, parent_password=None, ecc_curve=None, key_type='RSA', key_size=None, extra_extensions=None)[source]¶

Create a new certificate authority.

Parameters

namestr: The name of the CA. This is a human-readable string and is used for administrative purposes only.
subjectdict or str or Subject: Subject string, e.g. "/CN=example.com" or Subject("/CN=example.com"). The value is actually passed to Subject if it is not already an instance of that class.
expiresdatetime, optional: Datetime for when this certificate authority will expire, defaults to CA_DEFAULT_EXPIRES.
algorithmstr or HashAlgorithm, optional: Hash algorithm used when signing the certificate, passed to parse_hash_algorithm(). The default is the value of the CA_DIGEST_ALGORITHM setting.
parentCertificateAuthority, optional: Parent certificate authority for the new CA. Passing this value makes the CA an intermediate authority.
pathlenint, optional: Value of the path length attribute for the BasicConstraints extension.
issuer_urlstr: URL for the DER/ASN1 formatted certificate that is signing certificates.
issuer_alt_nameIssuerAlternativeName or str, optional: IssuerAlternativeName used when signing certificates. If the value is not an instance of IssuerAlternativeName, it will be passed as argument to the constructor of the class.
crl_urllist of str, optional: CRL URLs used for certificates signed by this CA.
ocsp_urlstr, optional: OCSP URL used for certificates signed by this CA.
ca_issuer_urlstr, optional: URL for the DER/ASN1 formatted certificate that is signing this CA. For intermediate CAs, this would usually be the issuer_url of the parent CA.
ca_crl_urllist of str, optional: CRL URLs used for this CA. This value is only meaningful for intermediate CAs.
ca_ocsp_urlstr, optional: OCSP URL used for this CA. This value is only meaningful for intermediate CAs.
name_constraintslist of lists or NameConstraints: List of names that this CA can sign and/or cannot sign. The value is passed to NameConstraints if the value is not already an instance of that class.
passwordbytes, optional: Password to encrypt the private key with.
parent_passwordbytes, optional: Password that the private key of the parent CA is encrypted with.
ecc_curvestr or EllipticCurve, optional: The elliptic curve to use for ECC type keys, passed verbatim to parse_key_curve().
key_type: str, optional: The type of private key to generate, must be one of "RSA", "DSA" or "ECC", with "RSA" being the default.
key_sizeint, optional: Integer specifying the key size, must be a power of two (e.g. 2048, 4096, …). Defaults to the CA_DEFAULT_KEY_SIZE, unused if key_type="ECC".
extra_extensionslist of cryptography.x509.Extension or django_ca.extensions.Extension, optional: An optional list of additional extensions to add to the certificate.

Raises

ValueError: For various cases of wrong input data (e.g. key_size not being the power of two).
PermissionError: If the private key file cannot be written to disk.

Certificate¶

class django_ca.models.Certificate(id, created, valid_from, expires, pub, cn, serial, revoked, revoked_date, revoked_reason, ca, csr)[source]¶

bundle¶: The complete certificate bundle. This includes all CAs as well as the certificates itself.

Manager methods¶

CertificateManager is the default manager for Certificate, meaning you can access it using Certificate.objects, e.g.:

>>> from django_ca.models import Certificate
>>> Certificate.objects.init(csr=csr, ca=ca, subject='/CN=example.com')
<Certificate: example.com>

class django_ca.managers.CertificateManager[source]¶

init(ca, csr, **kwargs)[source]¶

Create a signed certificate from a CSR and store it to the database.

All parameters are passed on to Certificate.objects.sign_cert().

sign_cert(ca, csr, expires=None, algorithm=None, subject=None, cn_in_san=True, csr_format=<Encoding.PEM: 'PEM'>, subject_alternative_name=None, key_usage=None, extended_key_usage=None, tls_feature=None, ocsp_no_check=False, extra_extensions=None, password=None)[source]¶

Create a signed certificate from a CSR.

PLEASE NOTE: This function creates the raw certificate and is usually not invoked directly. It is called by Certificate.objects.init(), which passes along all parameters unchanged and saves the raw certificate to the database.

Parameters

caCertificateAuthority: The certificate authority to sign the certificate with.
csrstr: A valid CSR. The format is given by the csr_format parameter.
expiresdatetime, optional: Datetime for when this certificate will expire, defaults to the CA_DEFAULT_EXPIRES setting.
algorithmstr or HashAlgorithm, optional: Hash algorithm used when signing the certificate, passed to parse_hash_algorithm(). The default is the value of the CA_DIGEST_ALGORITHM setting.
subjectdict or str or Subject: Subject string, e.g. "/CN=example.com" or Subject("/CN=example.com"). The value is actually passed to Subject if it is not already an instance of that class. If this value is not passed or if the value does not contain a CommonName, the first value of the subject_alternative_name parameter is used as CommonName.
cn_in_sanbool, optional: Wether the CommonName should also be included as subjectAlternativeName. The default is True, but the parameter is ignored if no CommonName is given. This is typically set to False when creating a client certificate, where the subjects CommonName has no meaningful value as subjectAlternativeName.
csr_formatEncoding, optional: The format of the CSR. The default is PEM.
subject_alternative_namelist of str or SubjectAlternativeName,: optional A list of alternative names for the certificate. The value is passed to SubjectAlternativeName if not already an instance of that class.
key_usagestr or dict or KeyUsage, optional: Value for the keyUsage X509 extension. The value is passed to KeyUsage if not already an instance of that class.
extended_key_usagestr or dict or ExtendedKeyUsage, optional: Value for the extendedKeyUsage X509 extension. The value is passed to ExtendedKeyUsage if not already an instance of that class.
tls_featurestr or dict or TLSFeature, optional: Value for the TLSFeature X509 extension. The value is passed to TLSFeature if not already an instance of that class.
ocsp_no_checkbool, optional: Add the OCSPNoCheck flag, indicating that an OCSP client should trust this certificate for it’s lifetime. This value only makes sense if you intend to use the certificate for an OCSP responder, the default is False. See RFC 6990, section 4.2.2.2.1 for more information.
extra_extensionslist of cryptography.x509.Extension or django_ca.extensions.Extension, optional: An optional list of additional extensions to add to the certificate.
passwordbytes, optional: Password used to load the private key of the certificate authority. If not passed, the private key is assumed to be unencrypted.

Returns

cryptography.x509.Certificate: The signed certificate.

X509CertMixin¶

X509CertMixin is a common base class to both CertificateAuthority and Certificate and provides many convenience attributes.

class django_ca.models.X509CertMixin(*args, **kwargs)[source]¶

authority_key_identifier¶: The AuthorityKeyIdentifier extension, or None if it doesn’t exist.

extended_key_usage¶: The ExtendedKeyUsage extension, or None if it doesn’t exist.

get_revocation_reason()[source]¶

Get the revocation reason of this certificate.

Note that this method is only used by cryptography>=2.4.

get_revocation_time()[source]¶

Get the revocation time as naive datetime.