X.509 Reference¶
Loading Certificates¶
-
cryptography.x509.
load_pem_x509_certificate
(data, backend=None)¶ New in version 0.7.
Deserialize a certificate from PEM encoded data. PEM certificates are base64 decoded and have delimiters that look like
-----BEGIN CERTIFICATE-----
.Parameters: - data (bytes) – The PEM encoded certificate data.
- backend – An optional backend supporting the
X509Backend
interface.
Returns: An instance of
Certificate
.>>> from cryptography import x509 >>> cert = x509.load_pem_x509_certificate(pem_data) >>> cert.serial_number 2
-
cryptography.x509.
load_der_x509_certificate
(data, backend=None)¶ New in version 0.7.
Deserialize a certificate from DER encoded data. DER is a binary format and is commonly found in files with the
.cer
extension (although file extensions are not a guarantee of encoding type).Parameters: - data (bytes) – The DER encoded certificate data.
- backend – An optional backend supporting the
X509Backend
interface.
Returns: An instance of
Certificate
.
Loading Certificate Revocation Lists¶
-
cryptography.x509.
load_pem_x509_crl
(data, backend=None)¶ New in version 1.1.
Deserialize a certificate revocation list (CRL) from PEM encoded data. PEM requests are base64 decoded and have delimiters that look like
-----BEGIN X509 CRL-----
.Parameters: - data (bytes) – The PEM encoded request data.
- backend – An optional backend supporting the
X509Backend
interface.
Returns: An instance of
CertificateRevocationList
.>>> from cryptography import x509 >>> from cryptography.hazmat.primitives import hashes >>> crl = x509.load_pem_x509_crl(pem_crl_data) >>> isinstance(crl.signature_hash_algorithm, hashes.SHA256) True
-
cryptography.x509.
load_der_x509_crl
(data, backend=None)¶ New in version 1.1.
Deserialize a certificate revocation list (CRL) from DER encoded data. DER is a binary format.
Parameters: - data (bytes) – The DER encoded request data.
- backend – An optional backend supporting the
X509Backend
interface.
Returns: An instance of
CertificateRevocationList
.
Loading Certificate Signing Requests¶
-
cryptography.x509.
load_pem_x509_csr
(data, backend=None)¶ New in version 0.9.
Deserialize a certificate signing request (CSR) from PEM encoded data. PEM requests are base64 decoded and have delimiters that look like
-----BEGIN CERTIFICATE REQUEST-----
. This format is also known as PKCS#10.Parameters: - data (bytes) – The PEM encoded request data.
- backend – An optional backend supporting the
X509Backend
interface.
Returns: An instance of
CertificateSigningRequest
.>>> from cryptography import x509 >>> from cryptography.hazmat.primitives import hashes >>> csr = x509.load_pem_x509_csr(pem_req_data) >>> isinstance(csr.signature_hash_algorithm, hashes.SHA256) True
-
cryptography.x509.
load_der_x509_csr
(data, backend=None)¶ New in version 0.9.
Deserialize a certificate signing request (CSR) from DER encoded data. DER is a binary format and is not commonly used with CSRs.
Parameters: - data (bytes) – The DER encoded request data.
- backend – An optional backend supporting the
X509Backend
interface.
Returns: An instance of
CertificateSigningRequest
.
X.509 Certificate Object¶
-
class
cryptography.x509.
Certificate
¶ New in version 0.7.
-
version
¶ Type: Version
The certificate version as an enumeration. Version 3 certificates are the latest version and also the only type you should see in practice.
Raises: cryptography.x509.InvalidVersion – If the version in the certificate is not a known X.509 version
.>>> cert.version <Version.v3: 2>
-
fingerprint
(algorithm)¶ Parameters: algorithm – The HashAlgorithm
that will be used to generate the fingerprint.Return bytes: The fingerprint using the supplied hash algorithm, as bytes. >>> from cryptography.hazmat.primitives import hashes >>> cert.fingerprint(hashes.SHA256()) b'\x86\xd2\x187Gc\xfc\xe7}[+E9\x8d\xb4\x8f\x10\xe5S\xda\x18u\xbe}a\x03\x08[\xac\xa04?'
-
public_key
()¶ The public key associated with the certificate.
Returns: One of RSAPublicKey
,DSAPublicKey
,EllipticCurvePublicKey
,Ed25519PublicKey
orEd448PublicKey
>>> from cryptography.hazmat.primitives.asymmetric import rsa >>> public_key = cert.public_key() >>> isinstance(public_key, rsa.RSAPublicKey) True
-
not_valid_before
¶ Type: datetime.datetime
A naïve datetime representing the beginning of the validity period for the certificate in UTC. This value is inclusive.
>>> cert.not_valid_before datetime.datetime(2010, 1, 1, 8, 30)
-
not_valid_after
¶ Type: datetime.datetime
A naïve datetime representing the end of the validity period for the certificate in UTC. This value is inclusive.
>>> cert.not_valid_after datetime.datetime(2030, 12, 31, 8, 30)
-
signature_hash_algorithm
¶ Type: HashAlgorithm
Returns the
HashAlgorithm
which was used in signing this certificate. Can beNone
if signature did not use separate hash (ED25519
,ED448
).>>> from cryptography.hazmat.primitives import hashes >>> isinstance(cert.signature_hash_algorithm, hashes.SHA256) True
-
signature_algorithm_oid
¶ New in version 1.6.
Type: ObjectIdentifier
Returns the
ObjectIdentifier
of the signature algorithm used to sign the certificate. This will be one of the OIDs fromSignatureAlgorithmOID
.>>> cert.signature_algorithm_oid <ObjectIdentifier(oid=1.2.840.113549.1.1.11, name=sha256WithRSAEncryption)>
-
extensions
¶ Type: Extensions
The extensions encoded in the certificate.
Raises: - cryptography.x509.DuplicateExtension – If more than one extension of the same type is found within the certificate.
- cryptography.x509.UnsupportedGeneralNameType – If an extension contains a general name that is not supported.
>>> for ext in cert.extensions: ... print(ext) <Extension(oid=<ObjectIdentifier(oid=2.5.29.35, name=authorityKeyIdentifier)>, critical=False, value=<AuthorityKeyIdentifier(key_identifier=b'\xe4}_\xd1\\\x95\x86\x08,\x05\xae\xbeu\xb6e\xa7\xd9]\xa8f', authority_cert_issuer=None, authority_cert_serial_number=None)>)> <Extension(oid=<ObjectIdentifier(oid=2.5.29.14, name=subjectKeyIdentifier)>, critical=False, value=<SubjectKeyIdentifier(digest=b'X\x01\x84$\x1b\xbc+R\x94J=\xa5\x10r\x14Q\xf5\xaf:\xc9')>)> <Extension(oid=<ObjectIdentifier(oid=2.5.29.15, name=keyUsage)>, critical=True, value=<KeyUsage(digital_signature=False, content_commitment=False, key_encipherment=False, data_encipherment=False, key_agreement=False, key_cert_sign=True, crl_sign=True, encipher_only=False, decipher_only=False)>)> <Extension(oid=<ObjectIdentifier(oid=2.5.29.32, name=certificatePolicies)>, critical=False, value=<CertificatePolicies([<PolicyInformation(policy_identifier=<ObjectIdentifier(oid=2.16.840.1.101.3.2.1.48.1, name=Unknown OID)>, policy_qualifiers=None)>])>)> <Extension(oid=<ObjectIdentifier(oid=2.5.29.19, name=basicConstraints)>, critical=True, value=<BasicConstraints(ca=True, path_length=None)>)>
-
tbs_certificate_bytes
¶ New in version 1.2.
Type: bytes The DER encoded bytes payload (as defined by RFC 5280) that is hashed and then signed by the private key of the certificate’s issuer. This data may be used to validate a signature, but use extreme caution as certificate validation is a complex problem that involves much more than just signature checks.
To validate the signature on a certificate you can do the following. Note: This only verifies that the certificate was signed with the private key associated with the public key provided and does not perform any of the other checks needed for secure certificate validation. Additionally, this example will only work for RSA public keys with
PKCS1v15
signatures, and so it can’t be used for general purpose signature verification.>>> from cryptography.hazmat.primitives.serialization import load_pem_public_key >>> from cryptography.hazmat.primitives.asymmetric import padding >>> issuer_public_key = load_pem_public_key(pem_issuer_public_key) >>> cert_to_check = x509.load_pem_x509_certificate(pem_data_to_check) >>> issuer_public_key.verify( ... cert_to_check.signature, ... cert_to_check.tbs_certificate_bytes, ... # Depends on the algorithm used to create the certificate ... padding.PKCS1v15(), ... cert_to_check.signature_hash_algorithm, ... ) An :class:`~cryptography.exceptions.InvalidSignature` exception will be raised if the signature fails to verify.
-
X.509 CRL (Certificate Revocation List) Object¶
-
class
cryptography.x509.
CertificateRevocationList
¶ New in version 1.0.
A CertificateRevocationList is an object representing a list of revoked certificates. The object is iterable and will yield the RevokedCertificate objects stored in this CRL.
>>> len(crl) 1 >>> revoked_certificate = crl[0] >>> type(revoked_certificate) <class 'cryptography.hazmat.backends.openssl.x509._RevokedCertificate'> >>> for r in crl: ... print(r.serial_number) 0
-
fingerprint
(algorithm)¶ Parameters: algorithm – The HashAlgorithm
that will be used to generate the fingerprint.Return bytes: The fingerprint using the supplied hash algorithm, as bytes. >>> from cryptography.hazmat.primitives import hashes >>> crl.fingerprint(hashes.SHA256()) b'e\xcf.\xc4:\x83?1\xdc\xf3\xfc\x95\xd7\xb3\x87\xb3\x8e\xf8\xb93!\x87\x07\x9d\x1b\xb4!\xb9\xe4W\xf4\x1f'
-
get_revoked_certificate_by_serial_number
(serial_number)¶ New in version 2.3.
Parameters: serial_number – The serial as a Python integer. Returns: RevokedCertificate
if theserial_number
is present in the CRL orNone
if it is not.
-
signature_hash_algorithm
¶ Type: HashAlgorithm
Returns the
HashAlgorithm
which was used in signing this CRL. Can beNone
if signature did not use separate hash (ED25519
,ED448
).>>> from cryptography.hazmat.primitives import hashes >>> isinstance(crl.signature_hash_algorithm, hashes.SHA256) True
-
signature_algorithm_oid
¶ New in version 1.6.
Type: ObjectIdentifier
Returns the
ObjectIdentifier
of the signature algorithm used to sign the CRL. This will be one of the OIDs fromSignatureAlgorithmOID
.>>> crl.signature_algorithm_oid <ObjectIdentifier(oid=1.2.840.113549.1.1.11, name=sha256WithRSAEncryption)>
-
next_update
¶ Type: datetime.datetime
A naïve datetime representing when the next update to this CRL is expected.
>>> crl.next_update datetime.datetime(2016, 1, 1, 0, 0)
-
last_update
¶ Type: datetime.datetime
A naïve datetime representing when this CRL was last updated.
>>> crl.last_update datetime.datetime(2015, 1, 1, 0, 0)
-
extensions
¶ Type: Extensions
The extensions encoded in the CRL.
-
tbs_certlist_bytes
¶ New in version 1.2.
Type: bytes The DER encoded bytes payload (as defined by RFC 5280) that is hashed and then signed by the private key of the CRL’s issuer. This data may be used to validate a signature, but use extreme caution as CRL validation is a complex problem that involves much more than just signature checks.
-
X.509 Certificate Builder¶
-
class
cryptography.x509.
CertificateBuilder
¶ New in version 1.0.
>>> from cryptography import x509 >>> from cryptography.hazmat.primitives import hashes >>> from cryptography.hazmat.primitives.asymmetric import rsa >>> from cryptography.x509.oid import NameOID >>> import datetime >>> one_day = datetime.timedelta(1, 0, 0) >>> private_key = rsa.generate_private_key( ... public_exponent=65537, ... key_size=2048, ... ) >>> public_key = private_key.public_key() >>> builder = x509.CertificateBuilder() >>> builder = builder.subject_name(x509.Name([ ... x509.NameAttribute(NameOID.COMMON_NAME, u'cryptography.io'), ... ])) >>> builder = builder.issuer_name(x509.Name([ ... x509.NameAttribute(NameOID.COMMON_NAME, u'cryptography.io'), ... ])) >>> builder = builder.not_valid_before(datetime.datetime.today() - one_day) >>> builder = builder.not_valid_after(datetime.datetime.today() + (one_day * 30)) >>> builder = builder.serial_number(x509.random_serial_number()) >>> builder = builder.public_key(public_key) >>> builder = builder.add_extension( ... x509.SubjectAlternativeName( ... [x509.DNSName(u'cryptography.io')] ... ), ... critical=False ... ) >>> builder = builder.add_extension( ... x509.BasicConstraints(ca=False, path_length=None), critical=True, ... ) >>> certificate = builder.sign( ... private_key=private_key, algorithm=hashes.SHA256(), ... ) >>> isinstance(certificate, x509.Certificate) True
-
issuer_name
(name)¶ Sets the issuer’s distinguished name.
Parameters: name – The Name
that describes the issuer (CA).
-
subject_name
(name)¶ Sets the subject’s distinguished name.
Parameters: name – The Name
that describes the subject.
-
public_key
(public_key)¶ Sets the subject’s public key.
Parameters: public_key – The subject’s public key. This can be one of RSAPublicKey
,DSAPublicKey
,EllipticCurvePublicKey
,Ed25519PublicKey
orEd448PublicKey
.
-
serial_number
(serial_number)¶ Sets the certificate’s serial number (an integer). The CA’s policy determines how it attributes serial numbers to certificates. This number must uniquely identify the certificate given the issuer. CABForum Guidelines require entropy in the serial number to provide protection against hash collision attacks. For more information on secure random number generation, see Random number generation.
Parameters: serial_number – Integer number that will be used by the CA to identify this certificate (most notably during certificate revocation checking). Users should consider using random_serial_number()
when possible.
-
not_valid_before
(time)¶ Sets the certificate’s activation time. This is the time from which clients can start trusting the certificate. It may be different from the time at which the certificate was created.
Parameters: time – The datetime.datetime
object (in UTC) that marks the activation time for the certificate. The certificate may not be trusted clients if it is used before this time.
-
not_valid_after
(time)¶ Sets the certificate’s expiration time. This is the time from which clients should no longer trust the certificate. The CA’s policy will determine how long the certificate should remain in use.
Parameters: time – The datetime.datetime
object (in UTC) that marks the expiration time for the certificate. The certificate may not be trusted clients if it is used after this time.
-
add_extension
(extval, critical)¶ Adds an X.509 extension to the certificate.
Parameters: - extval – An extension conforming to the
ExtensionType
interface. - critical – Set to
True
if the extension must be understood and handled by whoever reads the certificate.
- extval – An extension conforming to the
-
sign
(private_key, algorithm, backend=None)¶ Sign the certificate using the CA’s private key.
Parameters: - private_key – The
RSAPrivateKey
,DSAPrivateKey
,EllipticCurvePrivateKey
,Ed25519PrivateKey
orEd448PrivateKey
that will be used to sign the certificate. - algorithm – The
HashAlgorithm
that will be used to generate the signature. This must beNone
if theprivate_key
is anEd25519PrivateKey
or anEd448PrivateKey
and an instance of aHashAlgorithm
otherwise. - backend – An optional backend used to build the certificate.
Must support the
X509Backend
interface.
Returns: - private_key – The
-
X.509 CSR (Certificate Signing Request) Object¶
-
class
cryptography.x509.
CertificateSigningRequest
¶ New in version 0.9.
-
public_key
()¶ The public key associated with the request.
Returns: One of RSAPublicKey
,DSAPublicKey
,EllipticCurvePublicKey
,Ed25519PublicKey
orEd448PublicKey
.>>> from cryptography.hazmat.primitives.asymmetric import rsa >>> public_key = csr.public_key() >>> isinstance(public_key, rsa.RSAPublicKey) True
-
signature_hash_algorithm
¶ Type: HashAlgorithm
Returns the
HashAlgorithm
which was used in signing this request. Can beNone
if signature did not use separate hash (ED25519
,ED448
).>>> from cryptography.hazmat.primitives import hashes >>> isinstance(csr.signature_hash_algorithm, hashes.SHA256) True
-
signature_algorithm_oid
¶ New in version 1.6.
Type: ObjectIdentifier
Returns the
ObjectIdentifier
of the signature algorithm used to sign the request. This will be one of the OIDs fromSignatureAlgorithmOID
.>>> csr.signature_algorithm_oid <ObjectIdentifier(oid=1.2.840.113549.1.1.11, name=sha256WithRSAEncryption)>
-
extensions
¶ Type: Extensions
The extensions encoded in the certificate signing request.
Raises: - cryptography.x509.DuplicateExtension – If more than one extension of the same type is found within the certificate signing request.
- cryptography.x509.UnsupportedGeneralNameType – If an extension contains a general name that is not supported.
-
get_attribute_for_oid
(oid)¶ New in version 3.0.
Parameters: oid – An ObjectIdentifier
instance.Returns: The bytes value of the attribute or an exception if not found. Raises: cryptography.x509.AttributeNotFound – If the request does not have the attribute requested.
-
public_bytes
(encoding)¶ New in version 1.0.
Parameters: encoding – The Encoding
that will be used to serialize the certificate request.Return bytes: The data that can be written to a file or sent over the network to be signed by the certificate authority.
-
tbs_certrequest_bytes
¶ New in version 1.2.
Type: bytes The DER encoded bytes payload (as defined by RFC 2986) that is hashed and then signed by the private key (corresponding to the public key embedded in the CSR). This data may be used to validate the CSR signature.
-
is_signature_valid
¶ New in version 1.3.
Returns True if the CSR signature is correct, False otherwise.
-
X.509 Certificate Revocation List Builder¶
-
class
cryptography.x509.
CertificateRevocationListBuilder
¶ New in version 1.2.
>>> from cryptography import x509 >>> from cryptography.hazmat.primitives import hashes >>> from cryptography.hazmat.primitives.asymmetric import rsa >>> from cryptography.x509.oid import NameOID >>> import datetime >>> one_day = datetime.timedelta(1, 0, 0) >>> private_key = rsa.generate_private_key( ... public_exponent=65537, ... key_size=2048, ... ) >>> builder = x509.CertificateRevocationListBuilder() >>> builder = builder.issuer_name(x509.Name([ ... x509.NameAttribute(NameOID.COMMON_NAME, u'cryptography.io CA'), ... ])) >>> builder = builder.last_update(datetime.datetime.today()) >>> builder = builder.next_update(datetime.datetime.today() + one_day) >>> revoked_cert = x509.RevokedCertificateBuilder().serial_number( ... 333 ... ).revocation_date( ... datetime.datetime.today() ... ).build() >>> builder = builder.add_revoked_certificate(revoked_cert) >>> crl = builder.sign( ... private_key=private_key, algorithm=hashes.SHA256(), ... ) >>> len(crl) 1
-
issuer_name
(name)¶ Sets the issuer’s distinguished name.
Parameters: name – The Name
that describes the issuer (CA).
-
last_update
(time)¶ Sets this CRL’s activation time. This is the time from which clients can start trusting this CRL. It may be different from the time at which this CRL was created. This is also known as the
thisUpdate
time.Parameters: time – The datetime.datetime
object (in UTC) that marks the activation time for this CRL. The CRL may not be trusted if it is used before this time.
-
next_update
(time)¶ Sets this CRL’s next update time. This is the time by which a new CRL will be issued. The CA is allowed to issue a new CRL before this date, however clients are not required to check for it.
Parameters: time – The datetime.datetime
object (in UTC) that marks the next update time for this CRL.
-
add_extension
(extval, critical)¶ Adds an X.509 extension to this CRL.
Parameters: - extval – An extension with the
ExtensionType
interface. - critical – Set to
True
if the extension must be understood and handled by whoever reads the CRL.
- extval – An extension with the
-
add_revoked_certificate
(revoked_certificate)¶ Adds a revoked certificate to this CRL.
Parameters: revoked_certificate – An instance of RevokedCertificate
. These can be obtained from an existing CRL or created withRevokedCertificateBuilder
.
-
sign
(private_key, algorithm, backend=None)¶ Sign this CRL using the CA’s private key.
Parameters: - private_key – The
RSAPrivateKey
,DSAPrivateKey
,EllipticCurvePrivateKey
,Ed25519PrivateKey
orEd448PrivateKey
that will be used to sign the certificate. - algorithm – The
HashAlgorithm
that will be used to generate the signature. This must beNone
if theprivate_key
is anEd25519PrivateKey
or anEd448PrivateKey
and an instance of aHashAlgorithm
otherwise. - backend – An optional backend used to build the CRL.
Must support the
X509Backend
interface.
Returns: - private_key – The
-
X.509 Revoked Certificate Object¶
-
class
cryptography.x509.
RevokedCertificate
¶ New in version 1.0.
-
serial_number
¶ Type: int
An integer representing the serial number of the revoked certificate.
>>> revoked_certificate.serial_number 0
-
revocation_date
¶ Type: datetime.datetime
A naïve datetime representing the date this certificates was revoked.
>>> revoked_certificate.revocation_date datetime.datetime(2015, 1, 1, 0, 0)
-
extensions
¶ Type: Extensions
The extensions encoded in the revoked certificate.
>>> for ext in revoked_certificate.extensions: ... print(ext) <Extension(oid=<ObjectIdentifier(oid=2.5.29.24, name=invalidityDate)>, critical=False, value=<InvalidityDate(invalidity_date=2015-01-01 00:00:00)>)> <Extension(oid=<ObjectIdentifier(oid=2.5.29.21, name=cRLReason)>, critical=False, value=<CRLReason(reason=ReasonFlags.key_compromise)>)>
-
X.509 Revoked Certificate Builder¶
-
class
cryptography.x509.
RevokedCertificateBuilder
¶ This class is used to create
RevokedCertificate
objects that can be used with theCertificateRevocationListBuilder
.New in version 1.2.
>>> from cryptography import x509 >>> import datetime >>> builder = x509.RevokedCertificateBuilder() >>> builder = builder.revocation_date(datetime.datetime.today()) >>> builder = builder.serial_number(3333) >>> revoked_certificate = builder.build() >>> isinstance(revoked_certificate, x509.RevokedCertificate) True
-
serial_number
(serial_number)¶ Sets the revoked certificate’s serial number.
Parameters: serial_number – Integer number that is used to identify the revoked certificate.
-
revocation_date
(time)¶ Sets the certificate’s revocation date.
Parameters: time – The datetime.datetime
object (in UTC) that marks the revocation time for the certificate.
-
add_extension
(extval, critical)¶ Adds an X.509 extension to this revoked certificate.
Parameters: - extval – An instance of one of the CRL entry extensions.
- critical – Set to
True
if the extension must be understood and handled.
-
build
(backend=None)¶ Create a revoked certificate object using the provided backend.
Parameters: backend – An optional backend used to build the revoked certificate. Must support the X509Backend
interface.Returns: RevokedCertificate
-
X.509 CSR (Certificate Signing Request) Builder Object¶
-
class
cryptography.x509.
CertificateSigningRequestBuilder
¶ New in version 1.0.
>>> from cryptography import x509 >>> from cryptography.hazmat.primitives import hashes >>> from cryptography.hazmat.primitives.asymmetric import rsa >>> from cryptography.x509.oid import AttributeOID, NameOID >>> private_key = rsa.generate_private_key( ... public_exponent=65537, ... key_size=2048, ... ) >>> builder = x509.CertificateSigningRequestBuilder() >>> builder = builder.subject_name(x509.Name([ ... x509.NameAttribute(NameOID.COMMON_NAME, u'cryptography.io'), ... ])) >>> builder = builder.add_extension( ... x509.BasicConstraints(ca=False, path_length=None), critical=True, ... ) >>> builder = builder.add_attribute( ... AttributeOID.CHALLENGE_PASSWORD, b"changeit" ... ) >>> request = builder.sign( ... private_key, hashes.SHA256() ... ) >>> isinstance(request, x509.CertificateSigningRequest) True
-
subject_name
(name)¶ Parameters: name – The Name
of the certificate subject.Returns: A new CertificateSigningRequestBuilder
.
-
add_extension
(extension, critical)¶ Parameters: - extension – An extension conforming to the
ExtensionType
interface. - critical – Set to True if the extension must be understood and handled by whoever reads the certificate.
Returns: - extension – An extension conforming to the
-
add_attribute
(oid, value)¶ New in version 3.0.
Parameters: - oid – An
ObjectIdentifier
instance. - value (bytes) – The value of the attribute.
Returns: - oid – An
-
sign
(private_key, algorithm, backend=None)¶ Parameters: - backend – An optional backend used to sign the request.
Must support the
X509Backend
interface. - private_key – The
RSAPrivateKey
,DSAPrivateKey
,EllipticCurvePrivateKey
,Ed25519PrivateKey
orEd448PrivateKey
that will be used to sign the request. When the request is signed by a certificate authority, the private key’s associated public key will be stored in the resulting certificate. - algorithm – The
HashAlgorithm
that will be used to generate the request signature. This must beNone
if theprivate_key
is anEd25519PrivateKey
or anEd448PrivateKey
and an instance of aHashAlgorithm
otherwise.
Returns: A new
CertificateSigningRequest
.- backend – An optional backend used to sign the request.
Must support the
-
-
class
cryptography.x509.
Name
¶ New in version 0.8.
An X509 Name is an ordered list of attributes. The object is iterable to get every attribute or you can use
Name.get_attributes_for_oid()
to obtain the specific type you want. Names are sometimes represented as a slash or comma delimited string (e.g./CN=mydomain.com/O=My Org/C=US
orCN=mydomain.com,O=My Org,C=US
).Technically, a Name is a list of sets of attributes, called Relative Distinguished Names or RDNs, although multi-valued RDNs are rarely encountered. The iteration order of values within a multi-valued RDN is preserved. If you need to handle multi-valued RDNs, the
rdns
property gives access to an ordered list ofRelativeDistinguishedName
objects.A Name can be initialized with an iterable of
NameAttribute
(the common case where each RDN has a single attribute) or an iterable ofRelativeDistinguishedName
objects (in the rare case of multi-valued RDNs).>>> len(cert.subject) 3 >>> for attribute in cert.subject: ... print(attribute) <NameAttribute(oid=<ObjectIdentifier(oid=2.5.4.6, name=countryName)>, value='US')> <NameAttribute(oid=<ObjectIdentifier(oid=2.5.4.10, name=organizationName)>, value='Test Certificates 2011')> <NameAttribute(oid=<ObjectIdentifier(oid=2.5.4.3, name=commonName)>, value='Good CA')>
-
rdns
¶ New in version 1.6.
Type: list of RelativeDistinguishedName
-
get_attributes_for_oid
(oid)¶ Parameters: oid – An ObjectIdentifier
instance.Returns: A list of NameAttribute
instances that match the OID provided. If nothing matches an empty list will be returned.>>> cert.subject.get_attributes_for_oid(NameOID.COMMON_NAME) [<NameAttribute(oid=<ObjectIdentifier(oid=2.5.4.3, name=commonName)>, value='Good CA')>]
-
public_bytes
(backend=None)¶ New in version 1.6.
Parameters: backend – An optional backend supporting the X509Backend
interface.Return bytes: The DER encoded name.
-
-
class
cryptography.x509.
Version
¶ New in version 0.7.
An enumeration for X.509 versions.
-
v1
¶ For version 1 X.509 certificates.
-
v3
¶ For version 3 X.509 certificates.
-
-
class
cryptography.x509.
NameAttribute
¶ New in version 0.8.
An X.509 name consists of a list of
RelativeDistinguishedName
instances, which consist of a set ofNameAttribute
instances.-
oid
¶ Type: ObjectIdentifier
The attribute OID.
-
-
class
cryptography.x509.
RelativeDistinguishedName
(attributes)¶ New in version 1.6.
A relative distinguished name is a non-empty set of name attributes. The object is iterable to get every attribute, preserving the original order. Passing duplicate attributes to the constructor raises
ValueError
.-
get_attributes_for_oid
(oid)¶ Parameters: oid – An ObjectIdentifier
instance.Returns: A list of NameAttribute
instances that match the OID provided. The list should contain zero or one values.
-
-
class
cryptography.x509.
ObjectIdentifier
¶ New in version 0.8.
Object identifiers (frequently seen abbreviated as OID) identify the type of a value (see:
NameAttribute
).
General Name Classes¶
-
class
cryptography.x509.
GeneralName
¶ New in version 0.9.
This is the generic interface that all the following classes are registered against.
-
class
cryptography.x509.
RFC822Name
(value)¶ New in version 0.9.
This corresponds to an email address. For example,
user@example.com
.Parameters: value – The email address. If the address contains an internationalized domain name then it must be encoded to an A-label string before being passed. Raises: ValueError – If the provided string is not an A-label.
-
class
cryptography.x509.
DNSName
(value)¶ New in version 0.9.
This corresponds to a domain name. For example,
cryptography.io
.Parameters: value – The domain name. If it is an internationalized domain name then it must be encoded to an A-label string before being passed. Raises: ValueError – If the provided string is not an A-label.
type: text
-
class
cryptography.x509.
DirectoryName
(value)¶ New in version 0.9.
This corresponds to a directory name.
-
class
cryptography.x509.
UniformResourceIdentifier
(value)¶ New in version 0.9.
This corresponds to a uniform resource identifier. For example,
https://cryptography.io
.Parameters: value – The URI. If it contains an internationalized domain name then it must be encoded to an A-label string before being passed. Raises: ValueError – If the provided string is not an A-label.
-
class
cryptography.x509.
IPAddress
(value)¶ New in version 0.9.
This corresponds to an IP address.
-
value
¶ Type: IPv4Address
,IPv6Address
,IPv4Network
, orIPv6Network
.
-
-
class
cryptography.x509.
RegisteredID
(value)¶ New in version 0.9.
This corresponds to a registered ID.
-
value
¶ Type: ObjectIdentifier
-
-
class
cryptography.x509.
OtherName
(type_id, value)¶ New in version 1.0.
This corresponds to an
otherName.
AnotherName
has a type identifier and a value represented in binary DER format.-
type_id
¶ Type: ObjectIdentifier
-
X.509 Extensions¶
-
class
cryptography.x509.
Extensions
¶ New in version 0.9.
An X.509 Extensions instance is an ordered list of extensions. The object is iterable to get every extension.
-
get_extension_for_oid
(oid)¶ Parameters: oid – An ObjectIdentifier
instance.Returns: An instance of the extension class. Raises: cryptography.x509.ExtensionNotFound – If the certificate does not have the extension requested. >>> from cryptography.x509.oid import ExtensionOID >>> cert.extensions.get_extension_for_oid(ExtensionOID.BASIC_CONSTRAINTS) <Extension(oid=<ObjectIdentifier(oid=2.5.29.19, name=basicConstraints)>, critical=True, value=<BasicConstraints(ca=True, path_length=None)>)>
-
get_extension_for_class
(extclass)¶ New in version 1.1.
Parameters: extclass – An extension class. Returns: An instance of the extension class. Raises: cryptography.x509.ExtensionNotFound – If the certificate does not have the extension requested. >>> from cryptography import x509 >>> cert.extensions.get_extension_for_class(x509.BasicConstraints) <Extension(oid=<ObjectIdentifier(oid=2.5.29.19, name=basicConstraints)>, critical=True, value=<BasicConstraints(ca=True, path_length=None)>)>
-
-
class
cryptography.x509.
Extension
¶ New in version 0.9.
-
oid
¶ Type: ObjectIdentifier
One of the
ExtensionOID
OIDs.
-
critical
¶ Type: bool Determines whether a given extension is critical or not. RFC 5280 requires that “A certificate-using system MUST reject the certificate if it encounters a critical extension it does not recognize or a critical extension that contains information that it cannot process”.
-
value
¶ Returns an instance of the extension type corresponding to the OID.
-
-
class
cryptography.x509.
ExtensionType
¶ New in version 1.0.
This is the interface against which all the following extension types are registered.
-
class
cryptography.x509.
KeyUsage
(digital_signature, content_commitment, key_encipherment, data_encipherment, key_agreement, key_cert_sign, crl_sign, encipher_only, decipher_only)¶ New in version 0.9.
The key usage extension defines the purpose of the key contained in the certificate. The usage restriction might be employed when a key that could be used for more than one operation is to be restricted.
-
oid
¶ New in version 1.0.
Type: ObjectIdentifier
Returns
KEY_USAGE
.
-
digital_signature
¶ Type: bool This purpose is set to true when the subject public key is used for verifying digital signatures, other than signatures on certificates (
key_cert_sign
) and CRLs (crl_sign
).
-
content_commitment
¶ Type: bool This purpose is set to true when the subject public key is used for verifying digital signatures, other than signatures on certificates (
key_cert_sign
) and CRLs (crl_sign
). It is used to provide a non-repudiation service that protects against the signing entity falsely denying some action. In the case of later conflict, a reliable third party may determine the authenticity of the signed data. This was callednon_repudiation
in older revisions of the X.509 specification.
-
key_encipherment
¶ Type: bool This purpose is set to true when the subject public key is used for enciphering private or secret keys.
-
data_encipherment
¶ Type: bool This purpose is set to true when the subject public key is used for directly enciphering raw user data without the use of an intermediate symmetric cipher.
-
key_agreement
¶ Type: bool This purpose is set to true when the subject public key is used for key agreement. For example, when a Diffie-Hellman key is to be used for key management, then this purpose is set to true.
-
key_cert_sign
¶ Type: bool This purpose is set to true when the subject public key is used for verifying signatures on public key certificates. If this purpose is set to true then
ca
must be true in theBasicConstraints
extension.
-
crl_sign
¶ Type: bool This purpose is set to true when the subject public key is used for verifying signatures on certificate revocation lists.
-
encipher_only
¶ Type: bool When this purposes is set to true and the
key_agreement
purpose is also set, the subject public key may be used only for enciphering data while performing key agreement.Raises: ValueError – This is raised if accessed when key_agreement
is false.
-
decipher_only
¶ Type: bool When this purposes is set to true and the
key_agreement
purpose is also set, the subject public key may be used only for deciphering data while performing key agreement.Raises: ValueError – This is raised if accessed when key_agreement
is false.
-
-
class
cryptography.x509.
BasicConstraints
(ca, path_length)¶ New in version 0.9.
Basic constraints is an X.509 extension type that defines whether a given certificate is allowed to sign additional certificates and what path length restrictions may exist.
-
oid
¶ New in version 1.0.
Type: ObjectIdentifier
Returns
BASIC_CONSTRAINTS
.
-
path_length
¶ Type: int or None The maximum path length for certificates subordinate to this certificate. This attribute only has meaning if
ca
is true. Ifca
is true then a path length of None means there’s no restriction on the number of subordinate CAs in the certificate chain. If it is zero or greater then it defines the maximum length for a subordinate CA’s certificate chain. For example, apath_length
of 1 means the certificate can sign a subordinate CA, but the subordinate CA is not allowed to create subordinates withca
set to true.
-
-
class
cryptography.x509.
ExtendedKeyUsage
(usages)¶ New in version 0.9.
This extension indicates one or more purposes for which the certified public key may be used, in addition to or in place of the basic purposes indicated in the key usage extension. The object is iterable to obtain the list of
ExtendedKeyUsageOID
OIDs present.Parameters: usages (list) – A list of ExtendedKeyUsageOID
OIDs.-
oid
¶ New in version 1.0.
Type: ObjectIdentifier
Returns
EXTENDED_KEY_USAGE
.
-
-
class
cryptography.x509.
OCSPNoCheck
¶ New in version 1.0.
This presence of this extension indicates that an OCSP client can trust a responder for the lifetime of the responder’s certificate. CAs issuing such a certificate should realize that a compromise of the responder’s key is as serious as the compromise of a CA key used to sign CRLs, at least for the validity period of this certificate. CA’s may choose to issue this type of certificate with a very short lifetime and renew it frequently. This extension is only relevant when the certificate is an authorized OCSP responder.
-
oid
¶ New in version 1.0.
Type: ObjectIdentifier
Returns
OCSP_NO_CHECK
.
-
-
class
cryptography.x509.
TLSFeature
(features)¶ New in version 2.1.
The TLS Feature extension is defined in RFC 7633 and is used in certificates for OCSP Must-Staple. The object is iterable to get every element.
Parameters: features (list) – A list of features to enable from the TLSFeatureType
enum. At this time onlystatus_request
orstatus_request_v2
are allowed.-
oid
¶ Type: ObjectIdentifier
Returns
TLS_FEATURE
.
-
-
class
cryptography.x509.
TLSFeatureType
¶ New in version 2.1.
An enumeration of TLS Feature types.
-
class
cryptography.x509.
NameConstraints
(permitted_subtrees, excluded_subtrees)¶ New in version 1.0.
The name constraints extension, which only has meaning in a CA certificate, defines a name space within which all subject names in certificates issued beneath the CA certificate must (or must not) be in. For specific details on the way this extension should be processed see RFC 5280.
-
oid
¶ New in version 1.0.
Type: ObjectIdentifier
Returns
NAME_CONSTRAINTS
.
-
permitted_subtrees
¶ Type: list of GeneralName
objects or NoneThe set of permitted name patterns. If a name matches this and an element in
excluded_subtrees
it is invalid. At least one ofpermitted_subtrees
andexcluded_subtrees
will be non-None.
-
excluded_subtrees
¶ Type: list of GeneralName
objects or NoneAny name matching a restriction in the
excluded_subtrees
field is invalid regardless of information appearing in thepermitted_subtrees
. At least one ofpermitted_subtrees
andexcluded_subtrees
will be non-None.
-
-
class
cryptography.x509.
AuthorityKeyIdentifier
(key_identifier, authority_cert_issuer, authority_cert_serial_number)¶ New in version 0.9.
The authority key identifier extension provides a means of identifying the public key corresponding to the private key used to sign a certificate. This extension is typically used to assist in determining the appropriate certificate chain. For more information about generation and use of this extension see RFC 5280 section 4.2.1.1.
-
oid
¶ New in version 1.0.
Type: ObjectIdentifier
Returns
AUTHORITY_KEY_IDENTIFIER
.
-
key_identifier
¶ Type: bytes A value derived from the public key used to verify the certificate’s signature.
Type: A list of GeneralName
instances or NoneThe
GeneralName
(one or multiple) of the issuer’s issuer.
-
classmethod
from_issuer_public_key
(public_key)¶ New in version 1.0.
Note
This method should be used if the issuer certificate does not contain a
SubjectKeyIdentifier
. Otherwise, usefrom_issuer_subject_key_identifier()
.Creates a new AuthorityKeyIdentifier instance using the public key provided to generate the appropriate digest. This should be the issuer’s public key. The resulting object will contain
key_identifier
, butauthority_cert_issuer
andauthority_cert_serial_number
will be None. The generatedkey_identifier
is the SHA1 hash of thesubjectPublicKey
ASN.1 bit string. This is the first recommendation in RFC 5280 section 4.2.1.2.Parameters: public_key – One of RSAPublicKey
,DSAPublicKey
,EllipticCurvePublicKey
,Ed25519PublicKey
orEd448PublicKey
.>>> from cryptography import x509 >>> issuer_cert = x509.load_pem_x509_certificate(pem_data) >>> x509.AuthorityKeyIdentifier.from_issuer_public_key(issuer_cert.public_key()) <AuthorityKeyIdentifier(key_identifier=b'X\x01\x84$\x1b\xbc+R\x94J=\xa5\x10r\x14Q\xf5\xaf:\xc9', authority_cert_issuer=None, authority_cert_serial_number=None)>
-
classmethod
from_issuer_subject_key_identifier
(ski)¶ New in version 1.3.
Note
This method should be used if the issuer certificate contains a
SubjectKeyIdentifier
. Otherwise, usefrom_issuer_public_key()
.Creates a new AuthorityKeyIdentifier instance using the SubjectKeyIdentifier from the issuer certificate. The resulting object will contain
key_identifier
, butauthority_cert_issuer
andauthority_cert_serial_number
will be None.Parameters: ski – The SubjectKeyIdentifier
from the issuer certificate.>>> from cryptography import x509 >>> issuer_cert = x509.load_pem_x509_certificate(pem_data) >>> ski_ext = issuer_cert.extensions.get_extension_for_class(x509.SubjectKeyIdentifier) >>> x509.AuthorityKeyIdentifier.from_issuer_subject_key_identifier(ski_ext.value) <AuthorityKeyIdentifier(key_identifier=b'X\x01\x84$\x1b\xbc+R\x94J=\xa5\x10r\x14Q\xf5\xaf:\xc9', authority_cert_issuer=None, authority_cert_serial_number=None)>
-
-
class
cryptography.x509.
SubjectKeyIdentifier
(digest)¶ New in version 0.9.
The subject key identifier extension provides a means of identifying certificates that contain a particular public key.
-
oid
¶ New in version 1.0.
Type: ObjectIdentifier
Returns
SUBJECT_KEY_IDENTIFIER
.
-
classmethod
from_public_key
(public_key)¶ New in version 1.0.
Creates a new SubjectKeyIdentifier instance using the public key provided to generate the appropriate digest. This should be the public key that is in the certificate. The generated digest is the SHA1 hash of the
subjectPublicKey
ASN.1 bit string. This is the first recommendation in RFC 5280 section 4.2.1.2.Parameters: public_key – One of RSAPublicKey
,DSAPublicKey
,EllipticCurvePublicKey
,Ed25519PublicKey
orEd448PublicKey
.>>> from cryptography import x509 >>> csr = x509.load_pem_x509_csr(pem_req_data) >>> x509.SubjectKeyIdentifier.from_public_key(csr.public_key()) <SubjectKeyIdentifier(digest=b'\x8c"\x98\xe2\xb5\xbf]\xe8*2\xf8\xd2\'?\x00\xd2\xc7#\xe4c')>
-
-
class
cryptography.x509.
SubjectAlternativeName
(general_names)¶ New in version 0.9.
Subject alternative name is an X.509 extension that provides a list of general name instances that provide a set of identities for which the certificate is valid. The object is iterable to get every element.
Parameters: general_names (list) – A list of GeneralName
instances.-
oid
¶ New in version 1.0.
Type: ObjectIdentifier
Returns
SUBJECT_ALTERNATIVE_NAME
.
-
get_values_for_type
(type)¶ Parameters: type – A GeneralName
instance. This is one of the general name classes.Returns: A list of values extracted from the matched general names. The type of the returned values depends on the GeneralName
.>>> from cryptography import x509 >>> from cryptography.hazmat.primitives import hashes >>> cert = x509.load_pem_x509_certificate(cryptography_cert_pem) >>> # Get the subjectAltName extension from the certificate >>> ext = cert.extensions.get_extension_for_oid(ExtensionOID.SUBJECT_ALTERNATIVE_NAME) >>> # Get the dNSName entries from the SAN extension >>> ext.value.get_values_for_type(x509.DNSName) ['www.cryptography.io', 'cryptography.io']
-
-
class
cryptography.x509.
IssuerAlternativeName
(general_names)¶ New in version 1.0.
Issuer alternative name is an X.509 extension that provides a list of general name instances that provide a set of identities for the certificate issuer. The object is iterable to get every element.
Parameters: general_names (list) – A list of GeneralName
instances.-
oid
¶ New in version 1.0.
Type: ObjectIdentifier
Returns
ISSUER_ALTERNATIVE_NAME
.
-
get_values_for_type
(type)¶ Parameters: type – A GeneralName
instance. This is one of the general name classes.Returns: A list of values extracted from the matched general names.
-
-
class
cryptography.x509.
PrecertificateSignedCertificateTimestamps
(scts)¶ New in version 2.0.
This extension contains
SignedCertificateTimestamp
instances which were issued for the pre-certificate corresponding to this certificate. These can be used to verify that the certificate is included in a public Certificate Transparency log.It is an iterable containing one or more
SignedCertificateTimestamp
objects.Parameters: scts (list) – A list
ofSignedCertificateTimestamp
objects.-
oid
¶ Type: ObjectIdentifier
-
-
class
cryptography.x509.
PrecertPoison
¶ New in version 2.4.
This extension indicates that the certificate should not be treated as a certificate for the purposes of validation, but is instead for submission to a certificate transparency log in order to obtain SCTs which will be embedded in a
PrecertificateSignedCertificateTimestamps
extension on the final certificate.-
oid
¶ Type: ObjectIdentifier
Returns
PRECERT_POISON
.
-
-
class
cryptography.x509.
SignedCertificateTimestamps
(scts)¶ New in version 3.0.
This extension contains
SignedCertificateTimestamp
instances. These can be used to verify that the certificate is included in a public Certificate Transparency log. This extension is only found in OCSP responses. For SCTs in an X.509 certificate seePrecertificateSignedCertificateTimestamps
.It is an iterable containing one or more
SignedCertificateTimestamp
objects.Parameters: scts (list) – A list
ofSignedCertificateTimestamp
objects.-
oid
¶ Type: ObjectIdentifier
Returns
SIGNED_CERTIFICATE_TIMESTAMPS
.
-
-
class
cryptography.x509.
DeltaCRLIndicator
(crl_number)¶ New in version 2.1.
The delta CRL indicator is a CRL extension that identifies a CRL as being a delta CRL. Delta CRLs contain updates to revocation information previously distributed, rather than all the information that would appear in a complete CRL.
Parameters: crl_number (int) – The CRL number of the complete CRL that the delta CRL is updating. -
oid
¶ Type: ObjectIdentifier
Returns
DELTA_CRL_INDICATOR
.
-
-
class
cryptography.x509.
AuthorityInformationAccess
(descriptions)¶ New in version 0.9.
The authority information access extension indicates how to access information and services for the issuer of the certificate in which the extension appears. Information and services may include online validation services (such as OCSP) and issuer data. It is an iterable, containing one or more
AccessDescription
instances.Parameters: descriptions (list) – A list of AccessDescription
objects.-
oid
¶ New in version 1.0.
Type: ObjectIdentifier
Returns
AUTHORITY_INFORMATION_ACCESS
.
-
-
class
cryptography.x509.
SubjectInformationAccess
(descriptions)¶ New in version 3.0.
The subject information access extension indicates how to access information and services for the subject of the certificate in which the extension appears. When the subject is a CA, information and services may include certificate validation services and CA policy data. When the subject is an end entity, the information describes the type of services offered and how to access them. It is an iterable, containing one or more
AccessDescription
instances.Parameters: descriptions (list) – A list of AccessDescription
objects.-
oid
¶ Type: ObjectIdentifier
Returns
SUBJECT_INFORMATION_ACCESS
.
-
-
class
cryptography.x509.
AccessDescription
(access_method, access_location)¶ New in version 0.9.
-
access_method
¶ Type: ObjectIdentifier
The access method defines what the
access_location
means. It must beOCSP
orCA_ISSUERS
when used withAuthorityInformationAccess
orCA_REPOSITORY
when used withSubjectInformationAccess
.If it is
OCSP
the access location will be where to obtain OCSP information for the certificate. If it isCA_ISSUERS
the access location will provide additional information about the issuing certificate. Finally, if it isCA_REPOSITORY
the access location will be the location of the CA’s repository.
-
access_location
¶ Type: GeneralName
Where to access the information defined by the access method.
-
-
class
cryptography.x509.
FreshestCRL
(distribution_points)¶ New in version 2.1.
The freshest CRL extension (also known as Delta CRL Distribution Point) identifies how delta CRL information is obtained. It is an iterable, containing one or more
DistributionPoint
instances.Parameters: distribution_points (list) – A list of DistributionPoint
instances.-
oid
¶ Type: ObjectIdentifier
Returns
FRESHEST_CRL
.
-
-
class
cryptography.x509.
CRLDistributionPoints
(distribution_points)¶ New in version 0.9.
The CRL distribution points extension identifies how CRL information is obtained. It is an iterable, containing one or more
DistributionPoint
instances.Parameters: distribution_points (list) – A list of DistributionPoint
instances.-
oid
¶ New in version 1.0.
Type: ObjectIdentifier
Returns
CRL_DISTRIBUTION_POINTS
.
-
-
class
cryptography.x509.
DistributionPoint
(full_name, relative_name, reasons, crl_issuer)¶ New in version 0.9.
-
full_name
¶ Type: list of GeneralName
instances or NoneThis field describes methods to retrieve the CRL. At most one of
full_name
orrelative_name
will be non-None.
-
relative_name
¶ Type: RelativeDistinguishedName
or NoneThis field describes methods to retrieve the CRL relative to the CRL issuer. At most one of
full_name
orrelative_name
will be non-None.Changed in version 1.6: Changed from
Name
toRelativeDistinguishedName
.
-
crl_issuer
¶ Type: list of GeneralName
instances or NoneInformation about the issuer of the CRL.
-
reasons
¶ Type: frozenset of ReasonFlags
or NoneThe reasons a given distribution point may be used for when performing revocation checks.
-
-
class
cryptography.x509.
ReasonFlags
¶ New in version 0.9.
An enumeration for CRL reasons.
-
unspecified
¶ It is unspecified why the certificate was revoked. This reason cannot be used as a reason flag in a
DistributionPoint
.
-
key_compromise
¶ This reason indicates that the private key was compromised.
-
ca_compromise
¶ This reason indicates that the CA issuing the certificate was compromised.
-
affiliation_changed
¶ This reason indicates that the subject’s name or other information has changed.
-
superseded
¶ This reason indicates that a certificate has been superseded.
-
cessation_of_operation
¶ This reason indicates that the certificate is no longer required.
-
certificate_hold
¶ This reason indicates that the certificate is on hold.
-
privilege_withdrawn
¶ This reason indicates that the privilege granted by this certificate have been withdrawn.
-
aa_compromise
¶ When an attribute authority has been compromised.
-
remove_from_crl
¶ This reason indicates that the certificate was on hold and should be removed from the CRL. This reason cannot be used as a reason flag in a
DistributionPoint
.
-
-
class
cryptography.x509.
InhibitAnyPolicy
(skip_certs)¶ New in version 1.0.
The inhibit
anyPolicy
extension indicates that the special OIDANY_POLICY
, is not considered an explicit match for otherCertificatePolicies
except when it appears in an intermediate self-issued CA certificate. The value indicates the number of additional non-self-issued certificates that may appear in the path beforeANY_POLICY
is no longer permitted. For example, a value of one indicates thatANY_POLICY
may be processed in certificates issued by the subject of this certificate, but not in additional certificates in the path.-
oid
¶ New in version 1.0.
Type: ObjectIdentifier
Returns
INHIBIT_ANY_POLICY
.
-
-
class
cryptography.x509.
PolicyConstraints
¶ New in version 1.3.
The policy constraints extension is used to inhibit policy mapping or require that each certificate in a chain contain an acceptable policy identifier. For more information about the use of this extension see RFC 5280.
-
oid
¶ Type: ObjectIdentifier
Returns
POLICY_CONSTRAINTS
.
-
require_explicit_policy
¶ Type: int or None If this field is not None, the value indicates the number of additional certificates that may appear in the chain before an explicit policy is required for the entire path. When an explicit policy is required, it is necessary for all certificates in the chain to contain an acceptable policy identifier in the certificate policies extension. An acceptable policy identifier is the identifier of a policy required by the user of the certification path or the identifier of a policy that has been declared equivalent through policy mapping.
-
inhibit_policy_mapping
¶ Type: int or None If this field is not None, the value indicates the number of additional certificates that may appear in the chain before policy mapping is no longer permitted. For example, a value of one indicates that policy mapping may be processed in certificates issued by the subject of this certificate, but not in additional certificates in the chain.
-
-
class
cryptography.x509.
CRLNumber
(crl_number)¶ New in version 1.2.
The CRL number is a CRL extension that conveys a monotonically increasing sequence number for a given CRL scope and CRL issuer. This extension allows users to easily determine when a particular CRL supersedes another CRL. RFC 5280 requires that this extension be present in conforming CRLs.
-
oid
¶ Type: ObjectIdentifier
Returns
CRL_NUMBER
.
-
-
class
cryptography.x509.
IssuingDistributionPoint
(full_name, relative_name, only_contains_user_certs, only_contains_ca_certs, only_some_reasons, indirect_crl, only_contains_attribute_certs)¶ New in version 2.5.
Issuing distribution point is a CRL extension that identifies the CRL distribution point and scope for a particular CRL. It indicates whether the CRL covers revocation for end entity certificates only, CA certificates only, attribute certificates only, or a limited set of reason codes. For specific details on the way this extension should be processed see RFC 5280.
-
oid
¶ Type: ObjectIdentifier
Returns
ISSUING_DISTRIBUTION_POINT
.
-
only_contains_user_certs
¶ Type: bool Set to
True
if the CRL this extension is embedded within only contains information about user certificates.
-
only_contains_ca_certs
¶ Type: bool Set to
True
if the CRL this extension is embedded within only contains information about CA certificates.
-
indirect_crl
¶ Type: bool Set to
True
if the CRL this extension is embedded within includes certificates issued by one or more authorities other than the CRL issuer.
-
only_contains_attribute_certs
¶ Type: bool Set to
True
if the CRL this extension is embedded within only contains information about attribute certificates.
-
only_some_reasons
¶ Type: frozenset of ReasonFlags
or NoneThe reasons for which the issuing distribution point is valid. None indicates that it is valid for all reasons.
-
full_name
¶ Type: list of GeneralName
instances or NoneThis field describes methods to retrieve the CRL. At most one of
full_name
orrelative_name
will be non-None.
-
relative_name
¶ Type: RelativeDistinguishedName
or NoneThis field describes methods to retrieve the CRL relative to the CRL issuer. At most one of
full_name
orrelative_name
will be non-None.
-
-
class
cryptography.x509.
UnrecognizedExtension
¶ New in version 1.2.
A generic extension class used to hold the raw value of extensions that
cryptography
does not know how to parse. This can also be used when creating new certificates, CRLs, or OCSP requests and responses to encode extensions thatcryptography
does not know how to generate.-
oid
¶ Type: ObjectIdentifier
Returns the OID associated with this extension.
-
-
class
cryptography.x509.
CertificatePolicies
(policies)¶ New in version 0.9.
The certificate policies extension is an iterable, containing one or more
PolicyInformation
instances.Parameters: policies (list) – A list of PolicyInformation
instances.As an example of how
CertificatePolicies
might be used, if you wanted to check if a certificated contained the CAB Forum’s “domain-validated” policy, you might write code like:def contains_domain_validated(policies): return any( policy.oid.dotted_string == "2.23.140.1.2.1" for policy in policies )
-
oid
¶ New in version 1.0.
Type: ObjectIdentifier
Returns
CERTIFICATE_POLICIES
.
-
Certificate Policies Classes¶
These classes may be present within a CertificatePolicies
instance.
-
class
cryptography.x509.
PolicyInformation
(policy_identifier, policy_qualifiers)¶ New in version 0.9.
Contains a policy identifier and an optional list of qualifiers.
-
policy_identifier
¶ Type: ObjectIdentifier
-
policy_qualifiers
¶ Type: list A list consisting of text and/or
UserNotice
objects. If the value is text it is a pointer to the practice statement published by the certificate authority. If it is a user notice it is meant for display to the relying party when the certificate is used.
-
-
class
cryptography.x509.
UserNotice
(notice_reference, explicit_text)¶ New in version 0.9.
User notices are intended for display to a relying party when a certificate is used. In practice, few if any UIs expose this data and it is a rarely encoded component.
-
notice_reference
¶ Type: NoticeReference
or NoneThe notice reference field names an organization and identifies, by number, a particular statement prepared by that organization.
-
-
class
cryptography.x509.
NoticeReference
(organization, notice_numbers)¶ Notice reference can name an organization and provide information about notices related to the certificate. For example, it might identify the organization name and notice number 1. Application software could have a notice file containing the current set of notices for the named organization; the application would then extract the notice text from the file and display it. In practice this is rarely seen.
New in version 0.9.
CRL Entry Extensions¶
These extensions are only valid within a RevokedCertificate
object.
-
class
cryptography.x509.
CertificateIssuer
(general_names)¶ New in version 1.2.
The certificate issuer is an extension that is only valid inside
RevokedCertificate
objects. If theindirectCRL
property of the parent CRL’s IssuingDistributionPoint extension is set, then this extension identifies the certificate issuer associated with the revoked certificate. The object is iterable to get every element.Parameters: general_names (list) – A list of GeneralName
instances.-
oid
¶ Type: ObjectIdentifier
Returns
CERTIFICATE_ISSUER
.
-
get_values_for_type
(type)¶ Parameters: type – A GeneralName
instance. This is one of the general name classes.Returns: A list of values extracted from the matched general names. The type of the returned values depends on the GeneralName
.
-
-
class
cryptography.x509.
CRLReason
(reason)¶ New in version 1.2.
CRL reason (also known as
reasonCode
) is an extension that is only valid insideRevokedCertificate
objects. It identifies a reason for the certificate revocation.Parameters: reason – An element from ReasonFlags
.-
oid
¶ Type: ObjectIdentifier
Returns
CRL_REASON
.
-
reason
¶ Type: An element from ReasonFlags
-
-
class
cryptography.x509.
InvalidityDate
(invalidity_date)¶ New in version 1.2.
Invalidity date is an extension that is only valid inside
RevokedCertificate
objects. It provides the date on which it is known or suspected that the private key was compromised or that the certificate otherwise became invalid. This date may be earlier than the revocation date in the CRL entry, which is the date at which the CA processed the revocation.Parameters: invalidity_date – The datetime.datetime
when it is known or suspected that the private key was compromised.-
oid
¶ Type: ObjectIdentifier
Returns
INVALIDITY_DATE
.
-
invalidity_date
¶ Type: datetime.datetime
-
OCSP Extensions¶
-
class
cryptography.x509.
OCSPNonce
(nonce)¶ New in version 2.4.
OCSP nonce is an extension that is only valid inside
OCSPRequest
andOCSPResponse
objects. The nonce cryptographically binds a request and a response to prevent replay attacks. In practice nonces are rarely used in OCSP due to the desire to precompute OCSP responses at large scale.-
oid
¶ Type: ObjectIdentifier
Returns
NONCE
.
-
Object Identifiers¶
X.509 elements are frequently identified by ObjectIdentifier
instances. The following common OIDs are available as constants.
-
class
cryptography.x509.oid.
NameOID
¶ These OIDs are typically seen in X.509 names.
New in version 1.0.
-
COMMON_NAME
¶ Corresponds to the dotted string
"2.5.4.3"
. Historically the domain name would be encoded here for server certificates. RFC 2818 deprecates this practice and names of that type should now be located in aSubjectAlternativeName
extension.
-
COUNTRY_NAME
¶ Corresponds to the dotted string
"2.5.4.6"
.
-
LOCALITY_NAME
¶ Corresponds to the dotted string
"2.5.4.7"
.
-
STATE_OR_PROVINCE_NAME
¶ Corresponds to the dotted string
"2.5.4.8"
.
-
STREET_ADDRESS
¶ New in version 1.6.
Corresponds to the dotted string
"2.5.4.9"
.
-
ORGANIZATION_NAME
¶ Corresponds to the dotted string
"2.5.4.10"
.
-
ORGANIZATIONAL_UNIT_NAME
¶ Corresponds to the dotted string
"2.5.4.11"
.
-
SERIAL_NUMBER
¶ Corresponds to the dotted string
"2.5.4.5"
. This is distinct from the serial number of the certificate itself (which can be obtained withserial_number()
).
-
SURNAME
¶ Corresponds to the dotted string
"2.5.4.4"
.
-
GIVEN_NAME
¶ Corresponds to the dotted string
"2.5.4.42"
.
-
TITLE
¶ Corresponds to the dotted string
"2.5.4.12"
.
-
GENERATION_QUALIFIER
¶ Corresponds to the dotted string
"2.5.4.44"
.
-
X500_UNIQUE_IDENTIFIER
¶ New in version 1.6.
Corresponds to the dotted string
"2.5.4.45"
.
-
DN_QUALIFIER
¶ Corresponds to the dotted string
"2.5.4.46"
. This specifies disambiguating information to add to the relative distinguished name of an entry. See RFC 2256.
-
PSEUDONYM
¶ Corresponds to the dotted string
"2.5.4.65"
.
-
USER_ID
¶ New in version 1.6.
Corresponds to the dotted string
"0.9.2342.19200300.100.1.1"
.
-
DOMAIN_COMPONENT
¶ Corresponds to the dotted string
"0.9.2342.19200300.100.1.25"
. A string holding one component of a domain name. See RFC 4519.
-
EMAIL_ADDRESS
¶ Corresponds to the dotted string
"1.2.840.113549.1.9.1"
.
-
JURISDICTION_COUNTRY_NAME
¶ Corresponds to the dotted string
"1.3.6.1.4.1.311.60.2.1.3"
.
-
JURISDICTION_LOCALITY_NAME
¶ Corresponds to the dotted string
"1.3.6.1.4.1.311.60.2.1.1"
.
-
JURISDICTION_STATE_OR_PROVINCE_NAME
¶ Corresponds to the dotted string
"1.3.6.1.4.1.311.60.2.1.2"
.
-
BUSINESS_CATEGORY
¶ Corresponds to the dotted string
"2.5.4.15"
.
-
POSTAL_ADDRESS
¶ New in version 1.6.
Corresponds to the dotted string
"2.5.4.16"
.
-
POSTAL_CODE
¶ New in version 1.6.
Corresponds to the dotted string
"2.5.4.17"
.
-
UNSTRUCTURED_NAME
¶ New in version 3.0.
Corresponds to the dotted string
"1.2.840.113549.1.9.2"
.
-
-
class
cryptography.x509.oid.
SignatureAlgorithmOID
¶ New in version 1.0.
-
RSA_WITH_MD5
¶ Corresponds to the dotted string
"1.2.840.113549.1.1.4"
. This is an MD5 digest signed by an RSA key.
-
RSA_WITH_SHA1
¶ Corresponds to the dotted string
"1.2.840.113549.1.1.5"
. This is a SHA1 digest signed by an RSA key.
-
RSA_WITH_SHA224
¶ Corresponds to the dotted string
"1.2.840.113549.1.1.14"
. This is a SHA224 digest signed by an RSA key.
-
RSA_WITH_SHA256
¶ Corresponds to the dotted string
"1.2.840.113549.1.1.11"
. This is a SHA256 digest signed by an RSA key.
-
RSA_WITH_SHA384
¶ Corresponds to the dotted string
"1.2.840.113549.1.1.12"
. This is a SHA384 digest signed by an RSA key.
-
RSA_WITH_SHA512
¶ Corresponds to the dotted string
"1.2.840.113549.1.1.13"
. This is a SHA512 digest signed by an RSA key.
-
RSASSA_PSS
¶ New in version 2.3.
Corresponds to the dotted string
"1.2.840.113549.1.1.10"
. This is signed by an RSA key using the Probabilistic Signature Scheme (PSS) padding from RFC 4055. The hash function and padding are defined by signature algorithm parameters.
-
ECDSA_WITH_SHA1
¶ Corresponds to the dotted string
"1.2.840.10045.4.1"
. This is a SHA1 digest signed by an ECDSA key.
-
ECDSA_WITH_SHA224
¶ Corresponds to the dotted string
"1.2.840.10045.4.3.1"
. This is a SHA224 digest signed by an ECDSA key.
-
ECDSA_WITH_SHA256
¶ Corresponds to the dotted string
"1.2.840.10045.4.3.2"
. This is a SHA256 digest signed by an ECDSA key.
-
ECDSA_WITH_SHA384
¶ Corresponds to the dotted string
"1.2.840.10045.4.3.3"
. This is a SHA384 digest signed by an ECDSA key.
-
ECDSA_WITH_SHA512
¶ Corresponds to the dotted string
"1.2.840.10045.4.3.4"
. This is a SHA512 digest signed by an ECDSA key.
-
DSA_WITH_SHA1
¶ Corresponds to the dotted string
"1.2.840.10040.4.3"
. This is a SHA1 digest signed by a DSA key.
-
DSA_WITH_SHA224
¶ Corresponds to the dotted string
"2.16.840.1.101.3.4.3.1"
. This is a SHA224 digest signed by a DSA key.
-
DSA_WITH_SHA256
¶ Corresponds to the dotted string
"2.16.840.1.101.3.4.3.2"
. This is a SHA256 digest signed by a DSA key.
-
ED25519
¶ New in version 2.8.
Corresponds to the dotted string
"1.3.101.112"
. This is a signature using an ed25519 key.
-
ED448
¶ New in version 2.8.
Corresponds to the dotted string
"1.3.101.113"
. This is a signature using an ed448 key.
-
-
class
cryptography.x509.oid.
ExtendedKeyUsageOID
¶ New in version 1.0.
-
SERVER_AUTH
¶ Corresponds to the dotted string
"1.3.6.1.5.5.7.3.1"
. This is used to denote that a certificate may be used for TLS web server authentication.
-
CLIENT_AUTH
¶ Corresponds to the dotted string
"1.3.6.1.5.5.7.3.2"
. This is used to denote that a certificate may be used for TLS web client authentication.
-
CODE_SIGNING
¶ Corresponds to the dotted string
"1.3.6.1.5.5.7.3.3"
. This is used to denote that a certificate may be used for code signing.
-
EMAIL_PROTECTION
¶ Corresponds to the dotted string
"1.3.6.1.5.5.7.3.4"
. This is used to denote that a certificate may be used for email protection.
-
TIME_STAMPING
¶ Corresponds to the dotted string
"1.3.6.1.5.5.7.3.8"
. This is used to denote that a certificate may be used for time stamping.
-
OCSP_SIGNING
¶ Corresponds to the dotted string
"1.3.6.1.5.5.7.3.9"
. This is used to denote that a certificate may be used for signing OCSP responses.
-
ANY_EXTENDED_KEY_USAGE
¶ New in version 2.0.
Corresponds to the dotted string
"2.5.29.37.0"
. This is used to denote that a certificate may be used for _any_ purposes. However, RFC 5280 additionally notes that applications that require the presence of a particular purpose _MAY_ reject certificates that include theanyExtendedKeyUsage
OID but not the particular OID expected for the application. Therefore, the presence of this OID does not mean a given application will accept the certificate for all purposes.
-
-
class
cryptography.x509.oid.
AuthorityInformationAccessOID
¶ New in version 1.0.
-
OCSP
¶ Corresponds to the dotted string
"1.3.6.1.5.5.7.48.1"
. Used as the identifier for OCSP data inAccessDescription
objects.
-
CA_ISSUERS
¶ Corresponds to the dotted string
"1.3.6.1.5.5.7.48.2"
. Used as the identifier for CA issuer data inAccessDescription
objects.
-
-
class
cryptography.x509.oid.
SubjectInformationAccessOID
¶ New in version 3.0.
-
CA_REPOSITORY
¶ Corresponds to the dotted string
"1.3.6.1.5.5.7.48.5"
. Used as the identifier for CA repository data inAccessDescription
objects.
-
-
class
cryptography.x509.oid.
CertificatePoliciesOID
¶ New in version 1.0.
-
CPS_QUALIFIER
¶ Corresponds to the dotted string
"1.3.6.1.5.5.7.2.1"
.
-
CPS_USER_NOTICE
¶ Corresponds to the dotted string
"1.3.6.1.5.5.7.2.2"
.
-
ANY_POLICY
¶ Corresponds to the dotted string
"2.5.29.32.0"
.
-
-
class
cryptography.x509.oid.
ExtensionOID
¶ New in version 1.0.
-
BASIC_CONSTRAINTS
¶ Corresponds to the dotted string
"2.5.29.19"
. The identifier for theBasicConstraints
extension type.
-
KEY_USAGE
¶ Corresponds to the dotted string
"2.5.29.15"
. The identifier for theKeyUsage
extension type.
-
SUBJECT_ALTERNATIVE_NAME
¶ Corresponds to the dotted string
"2.5.29.17"
. The identifier for theSubjectAlternativeName
extension type.
-
ISSUER_ALTERNATIVE_NAME
¶ Corresponds to the dotted string
"2.5.29.18"
. The identifier for theIssuerAlternativeName
extension type.
-
SUBJECT_KEY_IDENTIFIER
¶ Corresponds to the dotted string
"2.5.29.14"
. The identifier for theSubjectKeyIdentifier
extension type.
-
NAME_CONSTRAINTS
¶ Corresponds to the dotted string
"2.5.29.30"
. The identifier for theNameConstraints
extension type.
-
CRL_DISTRIBUTION_POINTS
¶ Corresponds to the dotted string
"2.5.29.31"
. The identifier for theCRLDistributionPoints
extension type.
-
CERTIFICATE_POLICIES
¶ Corresponds to the dotted string
"2.5.29.32"
. The identifier for theCertificatePolicies
extension type.
-
AUTHORITY_KEY_IDENTIFIER
¶ Corresponds to the dotted string
"2.5.29.35"
. The identifier for theAuthorityKeyIdentifier
extension type.
-
EXTENDED_KEY_USAGE
¶ Corresponds to the dotted string
"2.5.29.37"
. The identifier for theExtendedKeyUsage
extension type.
-
AUTHORITY_INFORMATION_ACCESS
¶ Corresponds to the dotted string
"1.3.6.1.5.5.7.1.1"
. The identifier for theAuthorityInformationAccess
extension type.
-
SUBJECT_INFORMATION_ACCESS
¶ New in version 3.0.
Corresponds to the dotted string
"1.3.6.1.5.5.7.1.11"
. The identifier for theSubjectInformationAccess
extension type.
-
INHIBIT_ANY_POLICY
¶ Corresponds to the dotted string
"2.5.29.54"
. The identifier for theInhibitAnyPolicy
extension type.
-
OCSP_NO_CHECK
¶ Corresponds to the dotted string
"1.3.6.1.5.5.7.48.1.5"
. The identifier for theOCSPNoCheck
extension type.
-
TLS_FEATURE
¶ Corresponds to the dotted string
"1.3.6.1.5.5.7.1.24"
. The identifier for theTLSFeature
extension type.
-
CRL_NUMBER
¶ Corresponds to the dotted string
"2.5.29.20"
. The identifier for theCRLNumber
extension type. This extension only has meaning for certificate revocation lists.
-
DELTA_CRL_INDICATOR
¶ New in version 2.1.
Corresponds to the dotted string
"2.5.29.27"
. The identifier for theDeltaCRLIndicator
extension type. This extension only has meaning for certificate revocation lists.
-
PRECERT_SIGNED_CERTIFICATE_TIMESTAMPS
¶ New in version 1.9.
Corresponds to the dotted string
"1.3.6.1.4.1.11129.2.4.2"
.
-
PRECERT_POISON
¶ New in version 2.4.
Corresponds to the dotted string
"1.3.6.1.4.1.11129.2.4.3"
.
-
SIGNED_CERTIFICATE_TIMESTAMPS
¶ New in version 3.0.
Corresponds to the dotted string
"1.3.6.1.4.1.11129.2.4.5"
.
-
POLICY_CONSTRAINTS
¶ Corresponds to the dotted string
"2.5.29.36"
. The identifier for thePolicyConstraints
extension type.
-
FRESHEST_CRL
¶ Corresponds to the dotted string
"2.5.29.46"
. The identifier for theFreshestCRL
extension type.
-
ISSUING_DISTRIBUTION_POINT
¶ New in version 2.4.
Corresponds to the dotted string
"2.5.29.28"
.
-
-
class
cryptography.x509.oid.
CRLEntryExtensionOID
¶ New in version 1.2.
-
CERTIFICATE_ISSUER
¶ Corresponds to the dotted string
"2.5.29.29"
.
-
CRL_REASON
¶ Corresponds to the dotted string
"2.5.29.21"
.
-
INVALIDITY_DATE
¶ Corresponds to the dotted string
"2.5.29.24"
.
-
Helper Functions¶
-
cryptography.x509.
random_serial_number
()¶ New in version 1.6.
Generates a random serial number suitable for use when constructing certificates.
Exceptions¶
-
class
cryptography.x509.
InvalidVersion
¶ This is raised when an X.509 certificate has an invalid version number.
-
class
cryptography.x509.
DuplicateExtension
¶ This is raised when more than one X.509 extension of the same type is found within a certificate.
-
oid
¶ Type: ObjectIdentifier
Returns the OID.
-
-
class
cryptography.x509.
ExtensionNotFound
¶ This is raised when calling
Extensions.get_extension_for_oid()
with an extension OID that is not present in the certificate.-
oid
¶ Type: ObjectIdentifier
Returns the OID.
-
-
class
cryptography.x509.
AttributeNotFound
¶ This is raised when calling
CertificateSigningRequest.get_attribute_for_oid()
with an attribute OID that is not present in the request.-
oid
¶ Type: ObjectIdentifier
Returns the OID.
-
-
class
cryptography.x509.
UnsupportedGeneralNameType
¶ This is raised when a certificate contains an unsupported general name type in an extension.
-
type
¶ Type: int The integer value of the unsupported type. The complete list of types can be found in RFC 5280 section 4.2.1.6.
-