crypto — Generic cryptographic module

Note

pyca/cryptography is likely a better choice than using this module. It contains a complete set of cryptographic primitives as well as a significantly better and more powerful X509 API. If necessary you can convert to and from cryptography objects using the to_cryptography and from_cryptography methods on X509, X509Req, CRL, and PKey.

Elliptic curves

OpenSSL.crypto.get_elliptic_curves()

Return a set of objects representing the elliptic curves supported in the OpenSSL build in use.

The curve objects have a unicode name attribute by which they identify themselves.

The curve objects are useful as values for the argument accepted by Context.set_tmp_ecdh() to specify which elliptical curve should be used for ECDHE key exchange.

OpenSSL.crypto.get_elliptic_curve(name)

Return a single curve object selected by name.

See get_elliptic_curves() for information about curve objects.

Parameters

name (unicode) – The OpenSSL short name identifying the curve object to retrieve.

If the named curve is not supported then ValueError is raised.

Serialization and deserialization

The following serialization functions take one of these constants to determine the format.

OpenSSL.crypto.FILETYPE_PEM

FILETYPE_PEM serializes data to a Base64-encoded encoded representation of the underlying ASN.1 data structure. This representation includes delimiters that define what data structure is contained within the Base64-encoded block: for example, for a certificate, the delimiters are -----BEGIN CERTIFICATE----- and -----END CERTIFICATE-----.

OpenSSL.crypto.FILETYPE_ASN1

FILETYPE_ASN1 serializes data to the underlying ASN.1 data structure. The format used by FILETYPE_ASN1 is also sometimes referred to as DER.

Certificates

OpenSSL.crypto.dump_certificate(type, cert)

Dump the certificate cert into a buffer string encoded with the type type.

Parameters
  • type – The file type (one of FILETYPE_PEM, FILETYPE_ASN1, or FILETYPE_TEXT)

  • cert – The certificate to dump

Returns

The buffer with the dumped certificate in

OpenSSL.crypto.load_certificate(type, buffer)

Load a certificate (X509) from the string buffer encoded with the type type.

Parameters
  • type – The file type (one of FILETYPE_PEM, FILETYPE_ASN1)

  • buffer (bytes) – The buffer the certificate is stored in

Returns

The X509 object

Certificate signing requests

OpenSSL.crypto.dump_certificate_request(type, req)

Dump the certificate request req into a buffer string encoded with the type type.

Parameters
  • type – The file type (one of FILETYPE_PEM, FILETYPE_ASN1)

  • req – The certificate request to dump

Returns

The buffer with the dumped certificate request in

OpenSSL.crypto.load_certificate_request(type, buffer)

Load a certificate request (X509Req) from the string buffer encoded with the type type.

Parameters
  • type – The file type (one of FILETYPE_PEM, FILETYPE_ASN1)

  • buffer – The buffer the certificate request is stored in

Returns

The X509Req object

Private keys

OpenSSL.crypto.dump_privatekey(type, pkey, cipher=None, passphrase=None)

Dump the private key pkey into a buffer string encoded with the type type. Optionally (if type is FILETYPE_PEM) encrypting it using cipher and passphrase.

Parameters
  • type – The file type (one of FILETYPE_PEM, FILETYPE_ASN1, or FILETYPE_TEXT)

  • pkey (PKey) – The PKey to dump

  • cipher – (optional) if encrypted PEM format, the cipher to use

  • passphrase – (optional) if encrypted PEM format, this can be either the passphrase to use, or a callback for providing the passphrase.

Returns

The buffer with the dumped key in

Return type

bytes

OpenSSL.crypto.load_privatekey(type, buffer, passphrase=None)

Load a private key (PKey) from the string buffer encoded with the type type.

Parameters
  • type – The file type (one of FILETYPE_PEM, FILETYPE_ASN1)

  • buffer – The buffer the key is stored in

  • passphrase – (optional) if encrypted PEM format, this can be either the passphrase to use, or a callback for providing the passphrase.

Returns

The PKey object

Public keys

OpenSSL.crypto.dump_publickey(type, pkey)

Dump a public key to a buffer.

Parameters
Returns

The buffer with the dumped key in it.

Return type

bytes

OpenSSL.crypto.load_publickey(type, buffer)

Load a public key from a buffer.

Parameters
  • type – The file type (one of FILETYPE_PEM, FILETYPE_ASN1).

  • buffer (A Python string object, either unicode or bytestring.) – The buffer the key is stored in.

Returns

The PKey object.

Return type

PKey

Certificate revocation lists

OpenSSL.crypto.dump_crl(type, crl)

Dump a certificate revocation list to a buffer.

Parameters
  • type – The file type (one of FILETYPE_PEM, FILETYPE_ASN1, or FILETYPE_TEXT).

  • crl (CRL) – The CRL to dump.

Returns

The buffer with the CRL.

Return type

bytes

OpenSSL.crypto.load_crl(type, buffer)

Load Certificate Revocation List (CRL) data from a string buffer. buffer encoded with the type type.

Parameters
  • type – The file type (one of FILETYPE_PEM, FILETYPE_ASN1)

  • buffer – The buffer the CRL is stored in

Returns

The PKey object

OpenSSL.crypto.load_pkcs7_data(type, buffer)

Load pkcs7 data from the string buffer encoded with the type type.

Parameters
  • type – The file type (one of FILETYPE_PEM or FILETYPE_ASN1)

  • buffer – The buffer with the pkcs7 data.

Returns

The PKCS7 object

OpenSSL.crypto.load_pkcs12(buffer, passphrase=None)

Load pkcs12 data from the string buffer. If the pkcs12 structure is encrypted, a passphrase must be included. The MAC is always checked and thus required.

See also the man page for the C function PKCS12_parse().

Parameters
  • buffer – The buffer the certificate is stored in

  • passphrase – (Optional) The password to decrypt the PKCS12 lump

Returns

The PKCS12 object

Signing and verifying signatures

OpenSSL.crypto.sign(pkey, data, digest)

Sign a data string using the given key and message digest.

Parameters
  • pkey – PKey to sign with

  • data – data to be signed

  • digest – message digest to use

Returns

signature

New in version 0.11.

OpenSSL.crypto.verify(cert, signature, data, digest)

Verify the signature for a data string.

Parameters
  • cert – signing certificate (X509 object) corresponding to the private key which generated the signature.

  • signature – signature returned by sign function

  • data – data to be verified

  • digest – message digest to use

Returns

None if the signature is correct, raise exception otherwise.

New in version 0.11.

X509 objects

class OpenSSL.crypto.X509

An X.509 certificate.

add_extensions(extensions)

Add extensions to the certificate.

Parameters

extensions (An iterable of X509Extension objects.) – The extensions to add.

Returns

None

digest(digest_name)

Return the digest of the X509 object.

Parameters

digest_name (bytes) – The name of the digest algorithm to use.

Returns

The digest of the object, formatted as b":"-delimited hex pairs.

Return type

bytes

classmethod from_cryptography(crypto_cert)

Construct based on a cryptography crypto_cert.

Parameters

crypto_key (cryptography.x509.Certificate) – A cryptography X.509 certificate.

Return type

X509

New in version 17.1.0.

get_extension(index)

Get a specific extension of the certificate by index.

Extensions on a certificate are kept in order. The index parameter selects which extension will be returned.

Parameters

index (int) – The index of the extension to retrieve.

Returns

The extension at the specified index.

Return type

X509Extension

Raises

IndexError – If the extension index was out of bounds.

New in version 0.12.

get_extension_count()

Get the number of extensions on this certificate.

Returns

The number of extensions.

Return type

int

New in version 0.12.

get_issuer()

Return the issuer of this certificate.

This creates a new X509Name that wraps the underlying issuer name field on the certificate. Modifying it will modify the underlying certificate, and will have the effect of modifying any other X509Name that refers to this issuer.

Returns

The issuer of this certificate.

Return type

X509Name

get_notAfter()

Get the timestamp at which the certificate stops being valid.

The timestamp is formatted as an ASN.1 TIME:

YYYYMMDDhhmmssZ
Returns

A timestamp string, or None if there is none.

Return type

bytes or NoneType

get_notBefore()

Get the timestamp at which the certificate starts being valid.

The timestamp is formatted as an ASN.1 TIME:

YYYYMMDDhhmmssZ
Returns

A timestamp string, or None if there is none.

Return type

bytes or NoneType

get_pubkey()

Get the public key of the certificate.

Returns

The public key.

Return type

PKey

get_serial_number()

Return the serial number of this certificate.

Returns

The serial number.

Return type

int

get_signature_algorithm()

Return the signature algorithm used in the certificate.

Returns

The name of the algorithm.

Return type

bytes

Raises

ValueError – If the signature algorithm is undefined.

New in version 0.13.

get_subject()

Return the subject of this certificate.

This creates a new X509Name that wraps the underlying subject name field on the certificate. Modifying it will modify the underlying certificate, and will have the effect of modifying any other X509Name that refers to this subject.

Returns

The subject of this certificate.

Return type

X509Name

get_version()

Return the version number of the certificate.

Returns

The version number of the certificate.

Return type

int

gmtime_adj_notAfter(amount)

Adjust the time stamp on which the certificate stops being valid.

Parameters

amount (int) – The number of seconds by which to adjust the timestamp.

Returns

None

gmtime_adj_notBefore(amount)

Adjust the timestamp on which the certificate starts being valid.

Parameters

amount – The number of seconds by which to adjust the timestamp.

Returns

None

has_expired()

Check whether the certificate has expired.

Returns

True if the certificate has expired, False otherwise.

Return type

bool

set_issuer(issuer)

Set the issuer of this certificate.

Parameters

issuer (X509Name) – The issuer.

Returns

None

set_notAfter(when)

Set the timestamp at which the certificate stops being valid.

The timestamp is formatted as an ASN.1 TIME:

YYYYMMDDhhmmssZ
Parameters

when (bytes) – A timestamp string.

Returns

None

set_notBefore(when)

Set the timestamp at which the certificate starts being valid.

The timestamp is formatted as an ASN.1 TIME:

YYYYMMDDhhmmssZ
Parameters

when (bytes) – A timestamp string.

Returns

None

set_pubkey(pkey)

Set the public key of the certificate.

Parameters

pkey (PKey) – The public key.

Returns

None

set_serial_number(serial)

Set the serial number of the certificate.

Parameters

serial (int) – The new serial number.

Returns

:py:data`None`

set_subject(subject)

Set the subject of this certificate.

Parameters

subject (X509Name) – The subject.

Returns

None

set_version(version)

Set the version number of the certificate. Note that the version value is zero-based, eg. a value of 0 is V1.

Parameters

version (int) – The version number of the certificate.

Returns

None

sign(pkey, digest)

Sign the certificate with this key and digest type.

Parameters
  • pkey (PKey) – The key to sign with.

  • digest (bytes) – The name of the message digest to use.

Returns

None

subject_name_hash()

Return the hash of the X509 subject.

Returns

The hash of the subject.

Return type

bytes

to_cryptography()

Export as a cryptography certificate.

Return type

cryptography.x509.Certificate

New in version 17.1.0.

X509Name objects

class OpenSSL.crypto.X509Name(name)

An X.509 Distinguished Name.

Variables
  • countryName – The country of the entity.

  • C – Alias for countryName.

  • stateOrProvinceName – The state or province of the entity.

  • ST – Alias for stateOrProvinceName.

  • localityName – The locality of the entity.

  • L – Alias for localityName.

  • organizationName – The organization name of the entity.

  • O – Alias for organizationName.

  • organizationalUnitName – The organizational unit of the entity.

  • OU – Alias for organizationalUnitName

  • commonName – The common name of the entity.

  • CN – Alias for commonName.

  • emailAddress – The e-mail address of the entity.

__eq__(other)

Return self==value.

__ge__(other)

Return self>=value.

__gt__(other)

Return self>value.

__hash__ = None
__init__(name)

Create a new X509Name, copying the given X509Name instance.

Parameters

name (X509Name) – The name to copy.

__le__(other)

Return self<=value.

__lt__(other)

Return self<value.

__ne__(other)

Return self!=value.

__setattr__(name, value)

Implement setattr(self, name, value).

der()

Return the DER encoding of this name.

Returns

The DER encoded form of this name.

Return type

bytes

get_components()

Returns the components of this name, as a sequence of 2-tuples.

Returns

The components of this name.

Return type

list of name, value tuples.

hash()

Return an integer representation of the first four bytes of the MD5 digest of the DER representation of the name.

This is the Python equivalent of OpenSSL’s X509_NAME_hash.

Returns

The (integer) hash of this name.

Return type

int

X509Req objects

class OpenSSL.crypto.X509Req

An X.509 certificate signing requests.

__init__()
add_extensions(extensions)

Add extensions to the certificate signing request.

Parameters

extensions (iterable of X509Extension) – The X.509 extensions to add.

Returns

None

classmethod from_cryptography(crypto_req)

Construct based on a cryptography crypto_req.

Parameters

crypto_req (cryptography.x509.CertificateSigningRequest) – A cryptography X.509 certificate signing request

Return type

X509Req

New in version 17.1.0.

get_extensions()

Get X.509 extensions in the certificate signing request.

Returns

The X.509 extensions in this request.

Return type

list of X509Extension objects.

New in version 0.15.

get_pubkey()

Get the public key of the certificate signing request.

Returns

The public key.

Return type

PKey

get_subject()

Return the subject of this certificate signing request.

This creates a new X509Name that wraps the underlying subject name field on the certificate signing request. Modifying it will modify the underlying signing request, and will have the effect of modifying any other X509Name that refers to this subject.

Returns

The subject of this certificate signing request.

Return type

X509Name

get_version()

Get the version subfield (RFC 2459, section 4.1.2.1) of the certificate request.

Returns

The value of the version subfield.

Return type

int

set_pubkey(pkey)

Set the public key of the certificate signing request.

Parameters

pkey (PKey) – The public key to use.

Returns

None

set_version(version)

Set the version subfield (RFC 2459, section 4.1.2.1) of the certificate request.

Parameters

version (int) – The version number.

Returns

None

sign(pkey, digest)

Sign the certificate signing request with this key and digest type.

Parameters
  • pkey (PKey) – The key pair to sign with.

  • digest (bytes) – The name of the message digest to use for the signature, e.g. b"sha256".

Returns

None

to_cryptography()

Export as a cryptography certificate signing request.

Return type

cryptography.x509.CertificateSigningRequest

New in version 17.1.0.

verify(pkey)

Verifies the signature on this certificate signing request.

Parameters

key (PKey) – A public key.

Returns

True if the signature is correct.

Return type

bool

Raises

OpenSSL.crypto.Error – If the signature is invalid or there is a problem verifying the signature.

X509Store objects

class OpenSSL.crypto.X509Store

An X.509 store.

An X.509 store is used to describe a context in which to verify a certificate. A description of a context may include a set of certificates to trust, a set of certificate revocation lists, verification flags and more.

An X.509 store, being only a description, cannot be used by itself to verify a certificate. To carry out the actual verification process, see X509StoreContext.

add_cert(cert)

Adds a trusted certificate to this store.

Adding a certificate with this method adds this certificate as a trusted certificate.

Parameters

cert (X509) – The certificate to add to this store.

Raises
Returns

None if the certificate was added successfully.

add_crl(crl)

Add a certificate revocation list to this store.

The certificate revocation lists added to a store will only be used if the associated flags are configured to check certificate revocation lists.

New in version 16.1.0.

Parameters

crl (CRL) – The certificate revocation list to add to this store.

Returns

None if the certificate revocation list was added successfully.

load_locations(cafile, capath=None)

Let X509Store know where we can find trusted certificates for the certificate chain. Note that the certificates have to be in PEM format.

If capath is passed, it must be a directory prepared using the c_rehash tool included with OpenSSL. Either, but not both, of cafile or capath may be None.

Note

Both cafile and capath may be set simultaneously.

Call this method multiple times to add more than one location. For example, CA certificates, and certificate revocation list bundles may be passed in cafile in subsequent calls to this method.

New in version 20.0.

Parameters
  • cafile – In which file we can find the certificates (bytes or unicode).

  • capath – In which directory we can find the certificates (bytes or unicode).

Returns

None if the locations were set successfully.

Raises

OpenSSL.crypto.Error – If both cafile and capath is None or the locations could not be set for any reason.

set_flags(flags)

Set verification flags to this store.

Verification flags can be combined by oring them together.

Note

Setting a verification flag sometimes requires clients to add additional information to the store, otherwise a suitable error will be raised.

For example, in setting flags to enable CRL checking a suitable CRL must be added to the store otherwise an error will be raised.

New in version 16.1.0.

Parameters

flags (int) – The verification flags to set on this store. See X509StoreFlags for available constants.

Returns

None if the verification flags were successfully set.

set_time(vfy_time)

Set the time against which the certificates are verified.

Normally the current time is used.

Note

For example, you can determine if a certificate was valid at a given time.

New in version 17.0.0.

Parameters

vfy_time (datetime) – The verification time to set on this store.

Returns

None if the verification time was successfully set.

X509StoreContextError objects

class OpenSSL.crypto.X509StoreContextError(message, certificate)

An exception raised when an error occurred while verifying a certificate using OpenSSL.X509StoreContext.verify_certificate.

Variables

certificate – The certificate which caused verificate failure.

X509StoreContext objects

class OpenSSL.crypto.X509StoreContext(store, certificate, chain=None)

An X.509 store context.

An X.509 store context is used to carry out the actual verification process of a certificate in a described context. For describing such a context, see X509Store.

Variables
  • _store_ctx – The underlying X509_STORE_CTX structure used by this instance. It is dynamically allocated and automatically garbage collected.

  • _store – See the store __init__ parameter.

  • _cert – See the certificate __init__ parameter.

  • _chain – See the chain __init__ parameter.

Parameters
  • store (X509Store) – The certificates which will be trusted for the purposes of any verifications.

  • certificate (X509) – The certificate to be verified.

  • chain (list of X509) – List of untrusted certificates that may be used for building the certificate chain. May be None.

get_verified_chain()

Verify a certificate in a context and return the complete validated chain.

Raises

X509StoreContextError – If an error occurred when validating a certificate in the context. Sets certificate attribute to indicate which certificate caused the error.

New in version 20.0.

set_store(store)

Set the context’s X.509 store.

New in version 0.15.

Parameters

store (X509Store) – The store description which will be used for the purposes of any future verifications.

verify_certificate()

Verify a certificate in a context.

New in version 0.15.

Raises

X509StoreContextError – If an error occurred when validating a certificate in the context. Sets certificate attribute to indicate which certificate caused the error.

X509StoreFlags constants

class OpenSSL.crypto.X509StoreFlags

Flags for X509 verification, used to change the behavior of X509Store.

See OpenSSL Verification Flags for details.

CRL_CHECK
CRL_CHECK_ALL
IGNORE_CRITICAL
X509_STRICT
ALLOW_PROXY_CERTS
POLICY_CHECK
EXPLICIT_POLICY
INHIBIT_MAP
NOTIFY_POLICY
CHECK_SS_SIGNATURE

PKey objects

class OpenSSL.crypto.PKey

A class representing an DSA or RSA public key or key pair.

bits()

Returns the number of bits of the key

Returns

The number of bits of the key.

check()

Check the consistency of an RSA private key.

This is the Python equivalent of OpenSSL’s RSA_check_key.

Returns

True if key is consistent.

Raises
  • OpenSSL.crypto.Error – if the key is inconsistent.

  • TypeError – if the key is of a type which cannot be checked. Only RSA keys can currently be checked.

classmethod from_cryptography_key(crypto_key)

Construct based on a cryptography crypto_key.

Parameters

crypto_key (One of cryptography’s key interfaces.) – A cryptography key.

Return type

PKey

New in version 16.1.0.

generate_key(type, bits)

Generate a key pair of the given type, with the given number of bits.

This generates a key “into” the this object.

Parameters
  • type (TYPE_RSA or TYPE_DSA) – The key type.

  • bits (int >= 0) – The number of bits.

Raises
  • TypeError – If type or bits isn’t of the appropriate type.

  • ValueError – If the number of bits isn’t an integer of the appropriate size.

Returns

None

to_cryptography_key()

Export as a cryptography key.

Return type

One of cryptography’s key interfaces.

New in version 16.1.0.

type()

Returns the type of the key

Returns

The type of the key.

OpenSSL.crypto.TYPE_RSA
OpenSSL.crypto.TYPE_DSA

Key type constants.

PKCS7 objects

PKCS7 objects have the following methods:

class OpenSSL.crypto.PKCS7
get_type_name()

Returns the type name of the PKCS7 structure

Returns

A string with the typename

type_is_data()

Check if this NID_pkcs7_data object

Returns

True if the PKCS7 is of type data

type_is_enveloped()

Check if this NID_pkcs7_enveloped object

Returns

True if the PKCS7 is of type enveloped

type_is_signed()

Check if this NID_pkcs7_signed object

Returns

True if the PKCS7 is of type signed

type_is_signedAndEnveloped()

Check if this NID_pkcs7_signedAndEnveloped object

Returns

True if the PKCS7 is of type signedAndEnveloped

PKCS12 objects

class OpenSSL.crypto.PKCS12

A PKCS #12 archive.

export(passphrase=None, iter=2048, maciter=1)

Dump a PKCS12 object as a string.

For more information, see the PKCS12_create() man page.

Parameters
  • passphrase (bytes) – The passphrase used to encrypt the structure. Unlike some other passphrase arguments, this must be a string, not a callback.

  • iter (int) – Number of times to repeat the encryption step.

  • maciter (int) – Number of times to repeat the MAC step.

Returns

The string representation of the PKCS #12 structure.

Return type

get_ca_certificates()

Get the CA certificates in the PKCS #12 structure.

Returns

A tuple with the CA certificates in the chain, or None if there are none.

Return type

tuple of X509 or None

get_certificate()

Get the certificate in the PKCS #12 structure.

Returns

The certificate, or None if there is none.

Return type

X509 or None

get_friendlyname()

Get the friendly name in the PKCS# 12 structure.

Returns

The friendly name, or None if there is none.

Return type

bytes or None

get_privatekey()

Get the private key in the PKCS #12 structure.

Returns

The private key, or None if there is none.

Return type

PKey

set_ca_certificates(cacerts)

Replace or set the CA certificates within the PKCS12 object.

Parameters

cacerts (An iterable of X509 or None) – The new CA certificates, or None to unset them.

Returns

None

set_certificate(cert)

Set the certificate in the PKCS #12 structure.

Parameters

cert (X509 or None) – The new certificate, or None to unset it.

Returns

None

set_friendlyname(name)

Set the friendly name in the PKCS #12 structure.

Parameters

name (bytes or None) – The new friendly name, or None to unset.

Returns

None

set_privatekey(pkey)

Set the certificate portion of the PKCS #12 structure.

Parameters

pkey (PKey or None) – The new private key, or None to unset it.

Returns

None

X509Extension objects

class OpenSSL.crypto.X509Extension(type_name, critical, value, subject=None, issuer=None)

An X.509 v3 certificate extension.

__init__(type_name, critical, value, subject=None, issuer=None)

Initializes an X509 extension.

Parameters
  • type_name (bytes) – The name of the type of extension to create.

  • critical (bool) – A flag indicating whether this is a critical extension.

  • value (bytes) – The value of the extension.

  • subject (X509) – Optional X509 certificate to use as subject.

  • issuer (X509) – Optional X509 certificate to use as issuer.

__str__()
Returns

a nice text representation of the extension

get_critical()

Returns the critical field of this X.509 extension.

Returns

The critical field.

get_data()

Returns the data of the X509 extension, encoded as ASN.1.

Returns

The ASN.1 encoded data of this X509 extension.

Return type

bytes

New in version 0.12.

get_short_name()

Returns the short type name of this X.509 extension.

The result is a byte string such as b"basicConstraints".

Returns

The short type name.

Return type

bytes

New in version 0.12.

NetscapeSPKI objects

class OpenSSL.crypto.NetscapeSPKI

A Netscape SPKI object.

__init__()
b64_encode()

Generate a base64 encoded representation of this SPKI object.

Returns

The base64 encoded string.

Return type

bytes

get_pubkey()

Get the public key of this certificate.

Returns

The public key.

Return type

PKey

set_pubkey(pkey)

Set the public key of the certificate

Parameters

pkey – The public key

Returns

None

sign(pkey, digest)

Sign the certificate request with this key and digest type.

Parameters
  • pkey (PKey) – The private key to sign with.

  • digest (bytes) – The message digest to use.

Returns

None

verify(key)

Verifies a signature on a certificate request.

Parameters

key (PKey) – The public key that signature is supposedly from.

Returns

True if the signature is correct.

Return type

bool

Raises

OpenSSL.crypto.Error – If the signature is invalid, or there was a problem verifying the signature.

CRL objects

class OpenSSL.crypto.CRL

A certificate revocation list.

__init__()
add_revoked(revoked)

Add a revoked (by value not reference) to the CRL structure

This revocation will be added by value, not by reference. That means it’s okay to mutate it after adding: it won’t affect this CRL.

Parameters

revoked (Revoked) – The new revocation.

Returns

None

export(cert, key, type=1, days=100, digest=<object object>)

Export the CRL as a string.

Parameters
  • cert (X509) – The certificate used to sign the CRL.

  • key (PKey) – The key used to sign the CRL.

  • type (int) – The export format, either FILETYPE_PEM, FILETYPE_ASN1, or FILETYPE_TEXT.

  • days (int) – The number of days until the next update of this CRL.

  • digest (bytes) – The name of the message digest to use (eg b"sha256").

Return type

bytes

classmethod from_cryptography(crypto_crl)

Construct based on a cryptography crypto_crl.

Parameters

crypto_crl (cryptography.x509.CertificateRevocationList) – A cryptography certificate revocation list

Return type

CRL

New in version 17.1.0.

get_issuer()

Get the CRL’s issuer.

New in version 16.1.0.

Return type

X509Name

get_revoked()

Return the revocations in this certificate revocation list.

These revocations will be provided by value, not by reference. That means it’s okay to mutate them: it won’t affect this CRL.

Returns

The revocations in this CRL.

Return type

tuple of Revocation

set_lastUpdate(when)

Set when the CRL was last updated.

The timestamp is formatted as an ASN.1 TIME:

YYYYMMDDhhmmssZ

New in version 16.1.0.

Parameters

when (bytes) – A timestamp string.

Returns

None

set_nextUpdate(when)

Set when the CRL will next be updated.

The timestamp is formatted as an ASN.1 TIME:

YYYYMMDDhhmmssZ

New in version 16.1.0.

Parameters

when (bytes) – A timestamp string.

Returns

None

set_version(version)

Set the CRL version.

New in version 16.1.0.

Parameters

version (int) – The version of the CRL.

Returns

None

sign(issuer_cert, issuer_key, digest)

Sign the CRL.

Signing a CRL enables clients to associate the CRL itself with an issuer. Before a CRL is meaningful to other OpenSSL functions, it must be signed by an issuer.

This method implicitly sets the issuer’s name based on the issuer certificate and private key used to sign the CRL.

New in version 16.1.0.

Parameters
  • issuer_cert (X509) – The issuer’s certificate.

  • issuer_key (PKey) – The issuer’s private key.

  • digest (bytes) – The digest method to sign the CRL with.

to_cryptography()

Export as a cryptography CRL.

Return type

cryptography.x509.CertificateRevocationList

New in version 17.1.0.

Revoked objects

class OpenSSL.crypto.Revoked

A certificate revocation.

all_reasons()

Return a list of all the supported reason strings.

This list is a copy; modifying it does not change the supported reason strings.

Returns

A list of reason strings.

Return type

list of bytes

get_reason()

Get the reason of this revocation.

Returns

The reason, or None if there is none.

Return type

bytes or NoneType

See also

all_reasons(), which gives you a list of all supported reasons this method might return.

get_rev_date()

Get the revocation timestamp.

Returns

The timestamp of the revocation, as ASN.1 TIME.

Return type

bytes

get_serial()

Get the serial number.

The serial number is formatted as a hexadecimal number encoded in ASCII.

Returns

The serial number.

Return type

bytes

set_reason(reason)

Set the reason of this revocation.

If reason is None, delete the reason instead.

Parameters

reason (bytes or NoneType) – The reason string.

Returns

None

See also

all_reasons(), which gives you a list of all supported reasons which you might pass to this method.

set_rev_date(when)

Set the revocation timestamp.

Parameters

when (bytes) – The timestamp of the revocation, as ASN.1 TIME.

Returns

None

set_serial(hex_str)

Set the serial number.

The serial number is formatted as a hexadecimal number encoded in ASCII.

Parameters

hex_str (bytes) – The new serial number.

Returns

None

Exceptions

exception OpenSSL.crypto.Error

Generic exception used in the crypto module.

Digest names

Several of the functions and methods in this module take a digest name. These must be strings describing a digest algorithm supported by OpenSSL (by EVP_get_digestbyname, specifically). For example, b"sha256" or b"sha384".

More information and a list of these digest names can be found in the EVP_DigestInit(3) man page of your OpenSSL installation. This page can be found online for the latest version of OpenSSL: https://www.openssl.org/docs/manmaster/man3/EVP_DigestInit.html