Welcome to pyOpenSSL’s documentation!¶
Release v17.2.0 (What’s new?).
pyOpenSSL is a rather thin wrapper around (a subset of) the OpenSSL library. With thin wrapper we mean that a lot of the object methods do nothing more than calling a corresponding function in the OpenSSL library.
Contents:¶
Introduction¶
History¶
pyOpenSSL was originally created by Martin Sjögren because the SSL support in the standard library in Python 2.1 (the contemporary version of Python when the pyOpenSSL project was begun) was severely limited. Other OpenSSL wrappers for Python at the time were also limited, though in different ways.
Later it was maintained by Jean-Paul Calderone who among other things managed to make pyOpenSSL a pure Python project which the current maintainers are very grateful for.
Over the time the standard library’s ssl
module improved, never reaching the completeness of pyOpenSSL’s API coverage.
Despite PEP 466 many useful features remain Python 3-only and pyOpenSSL remains the only alternative for full-featured TLS code across all noteworthy Python versions from 2.6 through 3.5 and PyPy.
Development¶
pyOpenSSL is collaboratively developed by the Python Cryptography Authority (PyCA) that also maintains the low-level bindings called cryptography.
Current maintainer and release manager is Hynek Schlawack.
Contributing¶
First of all, thank you for your interest in contributing to pyOpenSSL! This project has no company backing its development therefore we’re dependent on help by the community.
Filing bug reports¶
Bug reports are very welcome. Please file them on the GitHub issue tracker. Good bug reports come with extensive descriptions of the error and how to reproduce it. Reporters are strongly encouraged to include an short, self contained, correct example.
Patches¶
All patches to pyOpenSSL should be submitted in the form of pull requests to the main pyOpenSSL repository, pyca/pyopenssl. These pull requests should satisfy the following properties:
Code¶
- The pull request should focus on one particular improvement to pyOpenSSL. Create different pull requests for unrelated features or bugfixes.
- Code should follow PEP 8, especially in the “do what code around you does” sense. Follow OpenSSL naming for callables whenever possible is preferred.
- Pull requests that introduce code must test all new behavior they introduce as well as for previously untested or poorly tested behavior that they touch.
- Pull requests are not allowed to break existing tests. We usually don’t comment on pull requests that are breaking the CI because we consider them work in progress. Please note that not having 100% code coverage for the code you wrote/touched also causes our CI to fail.
Documentation¶
When introducing new functionality, please remember to write documentation.
New functions and methods should have a docstring describing what they do, what parameters they takes, what types those parameters are, and what they return.
def dump_publickey(type, pkey): """ Dump a public key to a buffer. :param type: The file type (one of :data:`FILETYPE_PEM` or :data:`FILETYPE_ASN1`). :param PKey pkey: The PKey to dump. :return: The buffer with the dumped key in it. :rtype: bytes """
Don’t forget to add an
.. auto(function|class|method)::
statement to the relevant API document found indoc/api/
to actually add your function to the Sphinx documentation.Do not use
:py:
prefixes when cross-linking (Python is default). Do not use the generic:data:
or:obj:
. Instead use more specific types like:class:
,:func:
or:meth:
if applicable.Pull requests that introduce features or fix bugs should note those changes in the CHANGELOG.rst file. Please add new entries to the top of the current Changes section followed by a line linking to the relevant pull request:
- Added ``OpenSSL.crypto.some_func()`` to do something awesome. [`#1 <https://github.com/pyca/pyopenssl/pull/1>`_]
Use semantic newlines in reStructuredText files (files ending in
.rst
).
Review¶
Finally, pull requests must be reviewed before merging. This process mirrors the cryptography code review process. Everyone can perform reviews; this is a very valuable way to contribute, and is highly encouraged.
Pull requests are merged by members of PyCA.
They should, of course, keep all the requirements detailed in this document as well as the pyca/cryptography
merge requirements in mind.
The final responsibility for the reviewing of merged code lies with the person merging it. Since pyOpenSSL is a sensitive project from a security perspective, reviewers are strongly encouraged to take this review and merge process very seriously.
Finding Help¶
If you need any help with the contribution process, you’ll find us hanging out at #cryptography-dev
on Freenode IRC.
You can also ask questions on our mailing list.
Please note that this project is released with a Contributor Code of Conduct. By participating in this project you agree to abide by its terms.
Security¶
If you feel that you found a security-relevant bug that you would prefer to discuss in private, please send us a GPG-encrypted e-mail.
The maintainer can be reached at hs@ox.cx and his GPG key ID is 0xAE2536227F69F181
(Fingerprint: C2A0 4F86 ACE2 8ADC F817 DBB7 AE25 3622 7F69 F181
).
Feel free to cross-check this information with Keybase.
Installation¶
To install pyOpenSSL:
$ pip install pyopenssl
If you are installing in order to develop on pyOpenSSL, move to the root directory of a pyOpenSSL checkout, and run:
$ pip install -e .
Warning
As of 0.14, pyOpenSSL is a pure-Python project. That means that if you encounter any kind of compiler errors, pyOpenSSL’s bugtracker is the wrong place to report them because we cannot help you.
Please take the time to read the errors and report them/ask help from the appropriate project. The most likely culprit being cryptography that contains OpenSSL’s library bindings.
Supported OpenSSL Versions¶
pyOpenSSL supports the same platforms and releases as the upstream cryptography project does. Currently that means:
- 1.0.1
- 1.0.2
- 1.1.0
If you need support for older releases, the following pinned versions will work:
- OpenSSL 0.9.8:
'pyOpenSSL<17.0' 'cryptography<1.4'
- OpenSSL 1.0.0:
'pyOpenSSL<17.1' 'cryptography<1.7'
You can always find out the versions of pyOpenSSL, cryptography, and the linked OpenSSL by running python -m OpenSSL.debug
.
Documentation¶
The documentation is written in reStructuredText and built using Sphinx:
$ cd doc
$ make html
OpenSSL
— Python interface to OpenSSL¶
This package provides a high-level interface to the functions in the OpenSSL library. The following modules are defined:
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.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.
-
OpenSSL.crypto.
load_certificate
(type, buffer)¶ Load a certificate (X509) from the string buffer encoded with the type type.
Certificate signing requests¶
-
OpenSSL.crypto.
dump_certificate_request
(type, req)¶ Dump the certificate request req into a buffer string encoded with the type type.
-
OpenSSL.crypto.
load_certificate_request
(type, buffer)¶ Load a certificate request (X509Req) from the string buffer encoded with the type type.
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
, orFILETYPE_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: - type – The file type (one of
-
OpenSSL.crypto.
load_privatekey
(type, buffer[, passphrase])¶ Load a private key (PKey) from the string buffer encoded with the type type (must be one of
FILETYPE_PEM
andFILETYPE_ASN1
).passphrase must be either a string or a callback for providing the pass phrase.
Public keys¶
-
OpenSSL.crypto.
dump_publickey
(type, pkey)¶ Dump a public key to a buffer.
Parameters: - type – The file type (one of
FILETYPE_PEM
orFILETYPE_ASN1
). - pkey (PKey) – The public key to dump
Returns: The buffer with the dumped key in it.
Return type: - type – The file type (one of
-
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: - type – The file type (one of
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
, orFILETYPE_TEXT
). - crl (CRL) – The CRL to dump.
Returns: The buffer with the CRL.
Return type: - type – The file type (one of
-
OpenSSL.crypto.
load_crl
(type, buffer)¶ Load Certificate Revocation List (CRL) data from a string buffer. buffer encoded with the type type. The type type must either
FILETYPE_PEM
orFILETYPE_ASN1
).
-
OpenSSL.crypto.
load_pkcs7_data
(type, buffer)¶ Load pkcs7 data from the string buffer encoded with the type type. The type type must either
FILETYPE_PEM
orFILETYPE_ASN1
).
-
OpenSSL.crypto.
load_pkcs12
(buffer[, passphrase])¶ 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()
.
Signing and verifying signatures¶
-
OpenSSL.crypto.
sign
(key, data, digest)¶ Sign a data string using the given key and message digest.
key is a
PKey
instance. data is astr
instance. digest is astr
naming a supported message digest type, for exampleb"sha256"
.New in version 0.11.
-
OpenSSL.crypto.
verify
(certificate, signature, data, digest)¶ Verify the signature for a data string.
certificate is a
X509
instance corresponding to the private key which generated the signature. signature is a str instance giving the signature itself. data is a str instance giving the data to which the signature applies. digest is a str instance naming the message digest type of the signature, for exampleb"sha256"
.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
) – Acryptography
X.509 certificate.Return type: PKey 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 otherX509Name
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_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 otherX509Name
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.
Parameters: version ( int
) – The version number of the certificate.Returns: None
-
sign
(pkey, digest)¶ Sign the certificate with this key and digest type.
Parameters: Returns:
-
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.
-
__init__
(name)¶ Create a new X509Name, copying the given X509Name instance.
Parameters: name ( X509Name
) – The name to copy.
-
der
()¶ Return the DER encoding of this name.
Returns: The DER encoded form of this name. Return type: bytes
X509Req objects¶
-
class
OpenSSL.crypto.
X509Req
¶ An X.509 certificate signing requests.
-
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
) – Acryptography
X.509 certificate signing requestReturn type: PKey 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
ofX509Extension
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 otherX509Name
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: 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: - TypeError – If the certificate is not an
X509
. - OpenSSL.crypto.Error – If OpenSSL was unhappy with your certificate.
Returns: None
if the certificate was added successfully.- TypeError – If the certificate is not an
-
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.
-
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)¶ 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.
Parameters: -
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
¶
-
CB_ISSUER_CHECK
¶
-
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.) – Acryptography
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: Raises: - TypeError – If
type
orbits
isn’t of the appropriate type. - ValueError – If the number of bits isn’t an integer of the appropriate size.
Returns: None
- TypeError – If
-
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.
-
PKCS7 objects¶
PKCS7 objects have the following methods:
-
PKCS7.
type_is_signed
()¶ FIXME
-
PKCS7.
type_is_enveloped
()¶ FIXME
-
PKCS7.
type_is_signedAndEnveloped
()¶ FIXME
-
PKCS7.
type_is_data
()¶ FIXME
-
PKCS7.
get_type_name
()¶ Get the type name of the PKCS7.
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: - passphrase (
-
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
ofX509
orNone
-
get_certificate
()¶ Get the certificate in the PKCS #12 structure.
Returns: The certificate, or None
if there is none.Return type: X509
orNone
-
get_friendlyname
()¶ Get the friendly name in the PKCS# 12 structure.
Returns: The friendly name, or None
if there is none.Return type: bytes
orNone
-
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
orNone
) – The new CA certificates, orNone
to unset them.Returns: None
-
set_certificate
(cert)¶ Set the certificate in the PKCS #12 structure.
Parameters: cert ( X509
orNone
) – The new certificate, orNone
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.
- type_name (
-
__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.
-
b64_encode
()¶ Generate a base64 encoded representation of this SPKI object.
Returns: The base64 encoded string. Return type: bytes
-
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: 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.
-
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
, orFILETYPE_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"sha2566"
).
Return type:
-
classmethod
from_cryptography
(crypto_crl)¶ Construct based on a
cryptography
crypto_crl.Parameters: crypto_crl ( cryptography.x509.CertificateRevocationList
) – Acryptography
certificate revocation listReturn type: CRL New in version 17.1.0.
-
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
ofRevocation
-
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 udpated.
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:
-
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
ofbytes
-
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
isNone
, delete the reason instead.Parameters: reason ( bytes
orNoneType
) – 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.
-
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
SSL
— An interface to the SSL-specific parts of OpenSSL¶
This module handles things specific to SSL. There are two objects defined: Context, Connection.
-
OpenSSL.SSL.
SSLv2_METHOD
¶ -
OpenSSL.SSL.
SSLv3_METHOD
¶ -
OpenSSL.SSL.
SSLv23_METHOD
¶ -
OpenSSL.SSL.
TLSv1_METHOD
¶ -
OpenSSL.SSL.
TLSv1_1_METHOD
¶ -
OpenSSL.SSL.
TLSv1_2_METHOD
¶ These constants represent the different SSL methods to use when creating a context object. If the underlying OpenSSL build is missing support for any of these protocols, constructing a
Context
using the corresponding*_METHOD
will raise an exception.
-
OpenSSL.SSL.
VERIFY_NONE
¶ -
OpenSSL.SSL.
VERIFY_PEER
¶ -
OpenSSL.SSL.
VERIFY_FAIL_IF_NO_PEER_CERT
¶ These constants represent the verification mode used by the Context object’s
set_verify()
method.
-
OpenSSL.SSL.
FILETYPE_PEM
¶ -
OpenSSL.SSL.
FILETYPE_ASN1
¶ File type constants used with the
use_certificate_file()
anduse_privatekey_file()
methods of Context objects.
-
OpenSSL.SSL.
OP_SINGLE_DH_USE
¶ -
OpenSSL.SSL.
OP_SINGLE_ECDH_USE
¶ Constants used with
set_options()
of Context objects.When these options are used, a new key will always be created when using ephemeral (Elliptic curve) Diffie-Hellman.
-
OpenSSL.SSL.
OP_EPHEMERAL_RSA
¶ Constant used with
set_options()
of Context objects.When this option is used, ephemeral RSA keys will always be used when doing RSA operations.
-
OpenSSL.SSL.
OP_NO_TICKET
¶ Constant used with
set_options()
of Context objects.When this option is used, the session ticket extension will not be used.
-
OpenSSL.SSL.
OP_NO_COMPRESSION
¶ Constant used with
set_options()
of Context objects.When this option is used, compression will not be used.
-
OpenSSL.SSL.
OP_NO_SSLv2
¶ -
OpenSSL.SSL.
OP_NO_SSLv3
¶ -
OpenSSL.SSL.
OP_NO_TLSv1
¶ -
OpenSSL.SSL.
OP_NO_TLSv1_1
¶ -
OpenSSL.SSL.
OP_NO_TLSv1_2
¶ Constants used with
set_options()
of Context objects.Each of these options disables one version of the SSL/TLS protocol. This is interesting if you’re using e.g.
SSLv23_METHOD
to get an SSLv2-compatible handshake, but don’t want to use SSLv2. If the underlying OpenSSL build is missing support for any of these protocols, theOP_NO_*
constant may be undefined.
-
OpenSSL.SSL.
SSLEAY_VERSION
¶ -
OpenSSL.SSL.
SSLEAY_CFLAGS
¶ -
OpenSSL.SSL.
SSLEAY_BUILT_ON
¶ -
OpenSSL.SSL.
SSLEAY_PLATFORM
¶ -
OpenSSL.SSL.
SSLEAY_DIR
¶ Constants used with
SSLeay_version()
to specify what OpenSSL version information to retrieve. See the man page for theSSLeay_version()
C API for details.
-
OpenSSL.SSL.
SESS_CACHE_OFF
¶ -
OpenSSL.SSL.
SESS_CACHE_CLIENT
¶ -
OpenSSL.SSL.
SESS_CACHE_SERVER
¶ -
OpenSSL.SSL.
SESS_CACHE_BOTH
¶ -
OpenSSL.SSL.
SESS_CACHE_NO_AUTO_CLEAR
¶ -
OpenSSL.SSL.
SESS_CACHE_NO_INTERNAL_LOOKUP
¶ -
OpenSSL.SSL.
SESS_CACHE_NO_INTERNAL_STORE
¶ -
OpenSSL.SSL.
SESS_CACHE_NO_INTERNAL
¶ Constants used with
Context.set_session_cache_mode()
to specify the behavior of the session cache and potential session reuse. See the man page for theSSL_CTX_set_session_cache_mode()
C API for details.New in version 0.14.
-
OpenSSL.SSL.
OPENSSL_VERSION_NUMBER
¶ An integer giving the version number of the OpenSSL library used to build this version of pyOpenSSL. See the man page for the
SSLeay_version()
C API for details.
-
OpenSSL.SSL.
SSLeay_version
(type)¶ Retrieve a string describing some aspect of the underlying OpenSSL version. The type passed in should be one of the
SSLEAY_*
constants defined in this module.
-
class
OpenSSL.SSL.
Context
(method)¶ A class representing SSL contexts. Contexts define the parameters of one or more SSL connections.
method should be
SSLv2_METHOD
,SSLv3_METHOD
,SSLv23_METHOD
,TLSv1_METHOD
,TLSv1_1_METHOD
, orTLSv1_2_METHOD
.
-
class
OpenSSL.SSL.
Session
¶ A class representing an SSL session. A session defines certain connection parameters which may be re-used to speed up the setup of subsequent connections.
New in version 0.14.
-
OpenSSL.SSL.
ConnectionType
¶ See
Connection
.
-
class
OpenSSL.SSL.
Connection
(context, socket)¶ A class representing SSL connections.
context should be an instance of
Context
and socket should be a socket [1] object. socket may be None; in this case, the Connection is created with a memory BIO: see thebio_read()
,bio_write()
, andbio_shutdown()
methods.
-
exception
OpenSSL.SSL.
Error
¶ This exception is used as a base class for the other SSL-related exceptions, but may also be raised directly.
Whenever this exception is raised directly, it has a list of error messages from the OpenSSL error queue, where each item is a tuple (lib, function, reason). Here lib, function and reason are all strings, describing where and what the problem is. See err(3) for more information.
-
exception
OpenSSL.SSL.
ZeroReturnError
¶ This exception matches the error return code
SSL_ERROR_ZERO_RETURN
, and is raised when the SSL Connection has been closed. In SSL 3.0 and TLS 1.0, this only occurs if a closure alert has occurred in the protocol, i.e. the connection has been closed cleanly. Note that this does not necessarily mean that the transport layer (e.g. a socket) has been closed.It may seem a little strange that this is an exception, but it does match an
SSL_ERROR
code, and is very convenient.
-
exception
OpenSSL.SSL.
WantReadError
¶ The operation did not complete; the same I/O method should be called again later, with the same arguments. Any I/O method can lead to this since new handshakes can occur at any time.
The wanted read is for dirty data sent over the network, not the clean data inside the tunnel. For a socket based SSL connection, read means data coming at us over the network. Until that read succeeds, the attempted
OpenSSL.SSL.Connection.recv()
,OpenSSL.SSL.Connection.send()
, orOpenSSL.SSL.Connection.do_handshake()
is prevented or incomplete. You probably want toselect()
on the socket before trying again.
-
exception
OpenSSL.SSL.
WantWriteError
¶ See
WantReadError
. The socket send buffer may be too full to write more data.
-
exception
OpenSSL.SSL.
WantX509LookupError
¶ The operation did not complete because an application callback has asked to be called again. The I/O method should be called again later, with the same arguments.
Note
This won’t occur in this version, as there are no such callbacks in this version.
-
exception
OpenSSL.SSL.
SysCallError
¶ The
SysCallError
occurs when there’s an I/O error and OpenSSL’s error queue does not contain any information. This can mean two things: An error in the transport protocol, or an end of file that violates the protocol. The parameter to the exception is always a pair (errnum, errstr).
Context objects¶
Context objects have the following methods:
-
Context.
check_privatekey
()¶ Check if the private key (loaded with
use_privatekey()
) matches the certificate (loaded withuse_certificate()
). ReturnsNone
if they match, raisesError
otherwise.
-
Context.
get_app_data
()¶ Retrieve application data as set by
set_app_data()
.
-
Context.
get_cert_store
()¶ Retrieve the certificate store (a X509Store object) that the context uses. This can be used to add “trusted” certificates without using the
load_verify_locations()
method.
-
Context.
get_timeout
()¶ Retrieve session timeout, as set by
set_timeout()
. The default is 300 seconds.
-
Context.
get_verify_depth
()¶ Retrieve the Context object’s verify depth, as set by
set_verify_depth()
.
-
Context.
get_verify_mode
()¶ Retrieve the Context object’s verify mode, as set by
set_verify()
.
-
Context.
load_client_ca
(cafile)¶ Load the trusted certificates that will be sent to the client. Does not actually imply any of the certificates are trusted; that must be configured separately.
Parameters: cafile (bytes) – The path to a certificates file in PEM format. Returns: None
-
Context.
set_client_ca_list
(certificate_authorities)¶ Replace the current list of preferred certificate signers that would be sent to the client when requesting a client certificate with the certificate_authorities sequence of
OpenSSL.crypto.X509Name
‘s.New in version 0.10.
-
Context.
add_client_ca
(certificate_authority)¶ Extract a
OpenSSL.crypto.X509Name
from the certificate_authorityOpenSSL.crypto.X509
certificate and add it to the list of preferred certificate signers sent to the client when requesting a client certificate.New in version 0.10.
-
Context.
load_verify_locations
(pemfile, capath)¶ Specify where CA certificates for verification purposes are located. These are trusted certificates. 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 pemfile or capath may beNone
.
-
Context.
set_default_verify_paths
()¶ Specify that the platform provided CA certificates are to be used for verification purposes. This method has some caveats related to the binary wheels that cryptography (pyOpenSSL’s primary dependency) ships:
- macOS will only load certificates using this method if the user has the
openssl@1.1
Homebrew formula installed in the default location. - Windows will not work.
- manylinux1 cryptography wheels will work on most common Linux distributions in pyOpenSSL 17.1.0 and above. pyOpenSSL detects the manylinux1 wheel and attempts to load roots via a fallback path.
- macOS will only load certificates using this method if the user has the
-
Context.
load_tmp_dh
(dhfile)¶ Load parameters for Ephemeral Diffie-Hellman from dhfile.
-
Context.
set_tmp_ecdh
(curve)¶ Select a curve to use for ECDHE key exchange.
The valid values of curve are the objects returned by
OpenSSL.crypto.get_elliptic_curves()
orOpenSSL.crypto.get_elliptic_curve()
.
-
Context.
set_app_data
(data)¶ Associate data with this Context object. data can be retrieved later using the
get_app_data()
method.
-
Context.
set_cipher_list
(cipher_list)¶ Set the list of ciphers to be used in this context.
See the OpenSSL manual for more information (e.g. ciphers(1)).
Parameters: cipher_list (bytes) – An OpenSSL cipher string. Returns: None
-
Context.
set_info_callback
(callback)¶ Set the information callback to callback. This function will be called from time to time during SSL handshakes.
callback should take three arguments: a Connection object and two integers. The first integer specifies where in the SSL handshake the function was called, and the other the return code from a (possibly failed) internal function call.
-
Context.
set_options
(options)¶ Add SSL options. Options you have set before are not cleared! This method should be used with the
OP_*
constants.
-
Context.
set_mode
(mode)¶ Add SSL mode. Modes you have set before are not cleared! This method should be used with the
MODE_*
constants.
-
Context.
set_passwd_cb
(callback[, userdata])¶ Set the passphrase callback to callback. This function will be called when a private key with a passphrase is loaded. callback must accept three positional arguments. First, an integer giving the maximum length of the passphrase it may return. If the returned passphrase is longer than this, it will be truncated. Second, a boolean value which will be true if the user should be prompted for the passphrase twice and the callback should verify that the two values supplied are equal. Third, the value given as the userdata parameter to
set_passwd_cb()
. If an error occurs, callback should return a false value (e.g. an empty string).
-
Context.
set_session_cache_mode
(mode)¶ Set the behavior of the session cache used by all connections using this Context. The previously set mode is returned. See
SESS_CACHE_*
for details about particular modes.New in version 0.14.
-
Context.
get_session_cache_mode
()¶ Get the current session cache mode.
New in version 0.14.
-
Context.
set_session_id
(buf)¶ Set the session id to buf within which a session can be reused for this Context object. This is needed when doing session resumption, because there is no way for a stored session to know which Context object it is associated with.
Parameters: buf (bytes) – The session id. Returns: None
-
Context.
set_timeout
(timeout)¶ Set the timeout for newly created sessions for this Context object to timeout. timeout must be given in (whole) seconds. The default value is 300 seconds. See the OpenSSL manual for more information (e.g. SSL_CTX_set_timeout(3)).
-
Context.
set_verify
(mode, callback)¶ Set the verification flags for this Context object to mode and specify that callback should be used for verification callbacks. mode should be one of
VERIFY_NONE
andVERIFY_PEER
. IfVERIFY_PEER
is used, mode can be OR:ed withVERIFY_FAIL_IF_NO_PEER_CERT
andVERIFY_CLIENT_ONCE
to further control the behaviour.callback should take five arguments: A Connection object, an X509 object, and three integer variables, which are in turn potential error number, error depth and return code. callback should return true if verification passes and false otherwise.
-
Context.
set_verify_depth
(depth)¶ Set the maximum depth for the certificate chain verification that shall be allowed for this Context object.
-
Context.
use_certificate
(cert)¶ Use the certificate cert which has to be a X509 object.
-
Context.
add_extra_chain_cert
(cert)¶ Adds the certificate cert, which has to be a X509 object, to the certificate chain presented together with the certificate.
-
Context.
use_certificate_chain_file
(file)¶ Load a certificate chain from file which must be PEM encoded.
-
Context.
use_privatekey
(pkey)¶ Use the private key pkey which has to be a PKey object.
-
Context.
use_certificate_file
(file[, format])¶ Load the first certificate found in file. The certificate must be in the format specified by format, which is either
FILETYPE_PEM
orFILETYPE_ASN1
. The default isFILETYPE_PEM
.
-
Context.
use_privatekey_file
(file[, format])¶ Load the first private key found in file. The private key must be in the format specified by format, which is either
FILETYPE_PEM
orFILETYPE_ASN1
. The default isFILETYPE_PEM
.
-
Context.
set_tlsext_servername_callback
(callback)¶ Specify a one-argument callable to use as the TLS extension server name callback. When a connection using the server name extension is made using this context, the callback will be invoked with the
Connection
instance.New in version 0.13.
-
Context.
set_npn_advertise_callback
(callback)¶ Specify a callback function that will be called when offering Next Protocol Negotiation as a server.
callback should be the callback function. It will be invoked with one argument, the
Connection
instance. It should return a list of bytestrings representing the advertised protocols, like[b'http/1.1', b'spdy/2']
.New in version 0.15.
-
Context.set_npn_select_callback(callback):
Specify a callback function that will be called when a server offers Next Protocol Negotiation options.
callback should be the callback function. It will be invoked with two arguments: the
Connection
, and a list of offered protocols as bytestrings, e.g.[b'http/1.1', b'spdy/2']
. It should return one of those bytestrings, the chosen protocol.New in version 0.15.
-
Context.
set_alpn_protos
(protos)¶ Specify the protocols that the client is prepared to speak after the TLS connection has been negotiated using Application Layer Protocol Negotiation.
protos should be a list of protocols that the client is offering, each as a bytestring. For example,
[b'http/1.1', b'spdy/2']
.
-
Context.
set_alpn_select_callback
(callback)¶ Specify a callback function that will be called on the server when a client offers protocols using Application Layer Protocol Negotiation.
callback should be the callback function. It will be invoked with two arguments: the
Connection
and a list of offered protocols as bytestrings, e.g.[b'http/1.1', b'spdy/2']
. It should return one of these bytestrings, the chosen protocol.
Session objects¶
Session objects have no methods.
Connection objects¶
Connection objects have the following methods:
-
Connection.
accept
()¶ Call the
accept()
method of the underlying socket and set up SSL on the returned socket, using the Context object supplied to this Connection object at creation. Returns a pair (conn, address). where conn is the new Connection object created, and address is as returned by the socket’saccept()
.
-
Connection.
close
()¶ Call the
close()
method of the underlying socket. Note: If you want correct SSL closure, you need to call theshutdown()
method first.
-
Connection.
connect
(address)¶ Call the
connect()
method of the underlying socket and set up SSL on the socket, using the Context object supplied to this Connection object at creation.
-
Connection.
connect_ex
(address)¶ Call the
connect_ex()
method of the underlying socket and set up SSL on the socket, using the Context object supplied to this Connection object at creation. Note that if theconnect_ex()
method of the socket doesn’t return 0, SSL won’t be initialized.
-
Connection.
do_handshake
()¶ Perform an SSL handshake (usually called after
renegotiate()
or one ofset_accept_state()
orset_accept_state()
). This can raise the same exceptions assend()
andrecv()
.
-
Connection.
fileno
()¶ Retrieve the file descriptor number for the underlying socket.
-
Connection.
get_app_data
()¶ Retrieve application data as set by
set_app_data()
.
-
Connection.
get_cipher_list
()¶ Retrieve the list of ciphers used by the Connection object.
Returns: A list of native cipher strings.
-
Connection.
get_protocol_version
()¶ Retrieve the version of the SSL or TLS protocol used by the Connection. For example, it will return
0x769
for connections made over TLS version 1.
-
Connection.
get_protocol_version_name
()¶ Retrieve the version of the SSL or TLS protocol used by the Connection as a unicode string. For example, it will return
TLSv1
for connections made over TLS version 1, orUnknown
for connections that were not successfully established.
-
Connection.
get_client_ca_list
()¶ Retrieve the list of preferred client certificate issuers sent by the server as
OpenSSL.crypto.X509Name
objects.If this is a client
Connection
, the list will be empty until the connection with the server is established.If this is a server
Connection
, return the list of certificate authorities that will be sent or has been sent to the client, as controlled by thisConnection
‘sContext
.New in version 0.10.
-
Connection.
get_context
()¶ Retrieve the Context object associated with this Connection.
-
Connection.
set_context
(context)¶ Specify a replacement Context object for this Connection.
-
Connection.
get_peer_certificate
()¶ Retrieve the other side’s certificate (if any)
-
Connection.
get_peer_cert_chain
()¶ Retrieve the tuple of the other side’s certificate chain (if any)
-
Connection.
getpeername
()¶ Call the
getpeername()
method of the underlying socket.
-
Connection.
getsockname
()¶ Call the
getsockname()
method of the underlying socket.
-
Connection.
getsockopt
(level, optname[, buflen])¶ Call the
getsockopt()
method of the underlying socket.
-
Connection.
pending
()¶ Retrieve the number of bytes that can be safely read from the SSL buffer (not the underlying transport buffer).
-
Connection.
recv
(bufsize[, flags])¶ Receive data from the Connection. The return value is a string representing the data received. The maximum amount of data to be received at once, is specified by bufsize. The only supported flag is
MSG_PEEK
, all other flags are ignored.
-
Connection.
recv_into
(buffer[, nbytes[, flags]])¶ Receive data from the Connection and copy it directly into the provided buffer. The return value is the number of bytes read from the connection. The maximum amount of data to be received at once is specified by nbytes. The only supported flag is
MSG_PEEK
, all other flags are ignored.
-
Connection.
bio_write
(bytes)¶ If the Connection was created with a memory BIO, this method can be used to add bytes to the read end of that memory BIO. The Connection can then read the bytes (for example, in response to a call to
recv()
).
-
Connection.
renegotiate
()¶ Renegotiate the session.
Returns: True if the renegotiation can be started, False otherwise Return type: bool
-
Connection.
renegotiate_pending
()¶ Check if there’s a renegotiation in progress, it will return False once a renegotiation is finished.
Returns: Whether there’s a renegotiation in progress Return type: bool
-
Connection.
total_renegotiations
()¶ Find out the total number of renegotiations.
Returns: The number of renegotiations. Return type: int
-
Connection.
send
(string)¶ Send the string data to the Connection.
-
Connection.
bio_read
(bufsize)¶ If the Connection was created with a memory BIO, this method can be used to read bytes from the write end of that memory BIO. Many Connection methods will add bytes which must be read in this manner or the buffer will eventually fill up and the Connection will be able to take no further actions.
-
Connection.
sendall
(string)¶ Send all of the string data to the Connection. This calls
send()
repeatedly until all data is sent. If an error occurs, it’s impossible to tell how much data has been sent.
-
Connection.
set_accept_state
()¶ Set the connection to work in server mode. The handshake will be handled automatically by read/write.
-
Connection.
set_app_data
(data)¶ Associate data with this Connection object. data can be retrieved later using the
get_app_data()
method.
-
Connection.
set_connect_state
()¶ Set the connection to work in client mode. The handshake will be handled automatically by read/write.
-
Connection.
setblocking
(flag)¶ Call the
setblocking()
method of the underlying socket.
-
Connection.
setsockopt
(level, optname, value)¶ Call the
setsockopt()
method of the underlying socket.
-
Connection.
shutdown
()¶ Send the shutdown message to the Connection. Returns true if the shutdown message exchange is completed and false otherwise (in which case you call
recv()
orsend()
when the connection becomes readable/writeable.
-
Connection.
get_shutdown
()¶ Get the shutdown state of the Connection. Returns a bitvector of either or both of SENT_SHUTDOWN and RECEIVED_SHUTDOWN.
-
Connection.
set_shutdown
(state)¶ Set the shutdown state of the Connection. state is a bitvector of either or both of SENT_SHUTDOWN and RECEIVED_SHUTDOWN.
-
Connection.
sock_shutdown
(how)¶ Call the
shutdown()
method of the underlying socket.
-
Connection.
bio_shutdown
()¶ If the Connection was created with a memory BIO, this method can be used to indicate that end of file has been reached on the read end of that memory BIO.
-
Connection.
get_state_string
()¶ Retrieve a verbose string detailing the state of the Connection.
Returns: A string representing the state Return type: bytes
-
Connection.
client_random
()¶ Retrieve the random value used with the client hello message.
-
Connection.
server_random
()¶ Retrieve the random value used with the server hello message.
-
Connection.
master_key
()¶ Retrieve the value of the master key for this session.
-
Connection.
want_read
()¶ Checks if more data has to be read from the transport layer to complete an operation.
-
Connection.
want_write
()¶ Checks if there is data to write to the transport layer to complete an operation.
-
Connection.
set_tlsext_host_name
(name)¶ Specify the byte string to send as the server name in the client hello message.
New in version 0.13.
-
Connection.
get_servername
()¶ Get the value of the server name received in the client hello message.
New in version 0.13.
-
Connection.
get_session
()¶ Get a
Session
instance representing the SSL session in use by the connection, orNone
if there is no session.New in version 0.14.
-
Connection.
set_session
(session)¶ Set a new SSL session (using a
Session
instance) to be used by the connection.New in version 0.14.
-
Connection.
get_finished
()¶ Obtain latest TLS Finished message that we sent, or
None
if handshake is not completed.New in version 0.15.
-
Connection.
get_peer_finished
()¶ Obtain latest TLS Finished message that we expected from peer, or
None
if handshake is not completed.New in version 0.15.
-
Connection.
get_cipher_name
()¶ Obtain the name of the currently used cipher.
New in version 0.15.
-
Connection.
get_cipher_bits
()¶ Obtain the number of secret bits of the currently used cipher.
New in version 0.15.
-
Connection.
get_cipher_version
()¶ Obtain the protocol name of the currently used cipher.
New in version 0.15.
-
Connection.get_next_proto_negotiated():
Get the protocol that was negotiated by Next Protocol Negotiation. Returns a bytestring of the protocol name. If no protocol has been negotiated yet, returns an empty string.
New in version 0.15.
-
Connection.
set_alpn_protos
(protos)¶ Specify the protocols that the client is prepared to speak after the TLS connection has been negotiated using Application Layer Protocol Negotiation.
protos should be a list of protocols that the client is offering, each as a bytestring. For example,
[b'http/1.1', b'spdy/2']
.
-
Connection.
get_alpn_proto_negotiated
()¶ Get the protocol that was negotiated by Application Layer Protocol Negotiation. Returns a bytestring of the protocol name. If no protocol has been negotiated yet, returns an empty string.
Footnotes
[1] | Actually, all that is required is an object that behaves like a socket, you could even use files, even though it’d be tricky to get the handshakes right! |
Internals¶
We ran into three main problems developing this: Exceptions, callbacks and accessing socket methods. This is what this chapter is about.
Exceptions¶
We realized early that most of the exceptions would be raised by the I/O
functions of OpenSSL, so it felt natural to mimic OpenSSL’s error code system,
translating them into Python exceptions. This naturally gives us the exceptions
SSL.ZeroReturnError
, SSL.WantReadError
,
SSL.WantWriteError
, SSL.WantX509LookupError
and
SSL.SysCallError
.
For more information about this, see section SSL — An interface to the SSL-specific parts of OpenSSL.
Callbacks¶
Callbacks were more of a problem when pyOpenSSL was written in C. Having switched to being written in Python using cffi, callbacks are now straightforward. The problems that originally existed no longer do (if you are interested in the details you can find descriptions of those problems in the version control history for this document).
Accessing Socket Methods¶
We quickly saw the benefit of wrapping socket methods in the
SSL.Connection
class, for an easy transition into using SSL. The
problem here is that the socket
module lacks a C API, and all the
methods are declared static. One approach would be to have OpenSSL
as
a submodule to the socket
module, placing all the code in
socketmodule.c
, but this is obviously not a good solution, since you
might not want to import tonnes of extra stuff you’re not going to use when
importing the socket
module. The other approach is to somehow get a
pointer to the method to be called, either the C function, or a callable Python
object. This is not really a good solution either, since there’s a lot of
lookups involved.
The way it works is that you have to supply a socket
- like transport
object to the SSL.Connection
. The only requirement of this object is
that it has a fileno()
method that returns a file descriptor that’s
valid at the C level (i.e. you can use the system calls read and write). If you
want to use the connect()
or accept()
methods of the
SSL.Connection
object, the transport object has to supply such
methods too. Apart from them, any method lookups in the SSL.Connection
object that fail are passed on to the underlying transport object.
Future changes might be to allow Python-level transport objects, that instead
of having fileno()
methods, have read()
and write()
methods, so more advanced features of Python can be used. This would probably
entail some sort of OpenSSL BIOs, but converting Python strings back and
forth is expensive, so this shouldn’t be used unless necessary. Other nice
things would be to be able to pass in different transport objects for reading
and writing, but then the fileno()
method of SSL.Connection
becomes virtually useless. Also, should the method resolution be used on the
read-transport or the write-transport?
There are also examples in the pyOpenSSL repository that may help you getting started.
Meta¶
Backward Compatibility¶
pyOpenSSL has a very strong backward compatibility policy. Generally speaking, you shouldn’t ever be afraid of updating.
If breaking changes are needed do be done, they are:
- …announced in the Changelog.
- …the old behavior raises a
DeprecationWarning
for a year. - …are done with another announcement in the Changelog.
Changelog¶
Versions are year-based with a strict backward-compatibility policy. The third digit is only for regressions.
17.1.0 (2017-06-30)¶
Backward-incompatible changes:¶
- Removed the deprecated
OpenSSL.rand.egd()
function. Applications should preferos.urandom()
for random number generation. #630 - Removed the deprecated default
digest
argument toOpenSSL.crypto.CRL.export()
. Callers must now always pass an explicitdigest
. #652 - Fixed a bug with
ASN1_TIME
casting inX509.set_notBefore()
,X509.set_notAfter()
,Revoked.set_rev_date()
,Revoked.set_nextUpdate()
, andRevoked.set_lastUpdate()
. You must now pass times in the formYYYYMMDDhhmmssZ
.YYYYMMDDhhmmss+hhmm
andYYYYMMDDhhmmss-hhmm
will no longer work. #612
Deprecations:¶
- Deprecated the legacy “Type” aliases:
ContextType
,ConnectionType
,PKeyType
,X509NameType
,X509ExtensionType
,X509ReqType
,X509Type
,X509StoreType
,CRLType
,PKCS7Type
,PKCS12Type
,NetscapeSPKIType
. The names without the “Type”-suffix should be used instead.
Changes:¶
- Added
OpenSSL.crypto.X509.from_cryptography()
andOpenSSL.crypto.X509.to_cryptography()
for converting X.509 certificate to and from pyca/cryptography objects. #640 - Added
OpenSSL.crypto.X509Req.from_cryptography()
,OpenSSL.crypto.X509Req.to_cryptography()
,OpenSSL.crypto.CRL.from_cryptography()
, andOpenSSL.crypto.CRL.to_cryptography()
for converting X.509 CSRs and CRLs to and from pyca/cryptography objects. #645 - Added
OpenSSL.debug
that allows to get an overview of used library versions (including linked OpenSSL) and other useful runtime information usingpython -m OpenSSL.debug
. #620 - Added a fallback path to
Context.set_default_verify_paths()
to accommodate the upcoming release ofcryptography
manylinux1
wheels. #633
17.0.0 (2017-04-20)¶
Backward-incompatible changes:¶
none
Deprecations:¶
none
Changes:¶
- Added
OpenSSL.X509Store.set_time()
to set a custom verification time when verifying certificate chains. #567 - Added a collection of functions for working with OCSP stapling.
None of these functions make it possible to validate OCSP assertions, only to staple them into the handshake and to retrieve the stapled assertion if provided.
Users will need to write their own code to handle OCSP assertions.
We specifically added:
Context.set_ocsp_server_callback()
,Context.set_ocsp_client_callback()
, andConnection.request_ocsp()
. #580 - Changed the
SSL
module’s memory allocation policy to avoid zeroing memory it allocates when unnecessary. This reduces CPU usage and memory allocation time by an amount proportional to the size of the allocation. For applications that process a lot of TLS data or that use very lage allocations this can provide considerable performance improvements. #578 - Automatically set
SSL_CTX_set_ecdh_auto()
onOpenSSL.SSL.Context
. #575 - Fix empty exceptions from
OpenSSL.crypto.load_privatekey()
. #581
16.1.0 (2016-08-26)¶
Backward-incompatible changes:¶
none
Deprecations:¶
- Dropped support for OpenSSL 0.9.8.
Changes:¶
- Fix memory leak in
OpenSSL.crypto.dump_privatekey()
withFILETYPE_TEXT
. #496 - Enable use of CRL (and more) in verify context. #483
OpenSSL.crypto.PKey
can now be constructed fromcryptography
objects and also exported as such. #439- Support newer versions of
cryptography
which use opaque structs for OpenSSL 1.1.0 compatibility.
16.0.0 (2016-03-19)¶
This is the first release under full stewardship of PyCA. We have made many changes to make local development more pleasing. The test suite now passes both on Linux and OS X with OpenSSL 0.9.8, 1.0.1, and 1.0.2. It has been moved to pytest, all CI test runs are part of tox and the source code has been made fully flake8 compliant.
We hope to have lowered the barrier for contributions significantly but are open to hear about any remaining frustrations.
Backward-incompatible changes:¶
- Python 3.2 support has been dropped.
It never had significant real world usage and has been dropped by our main dependency
cryptography
. Affected users should upgrade to Python 3.3 or later.
Deprecations:¶
The support for EGD has been removed. The only affected function
OpenSSL.rand.egd()
now usesos.urandom()
to seed the internal PRNG instead. Please see pyca/cryptography#1636 for more background information on this decision. In accordance with our backward compatibility policyOpenSSL.rand.egd()
will be removed no sooner than a year from the release of 16.0.0.Please note that you should use urandom for all your secure random number needs.
Python 2.6 support has been deprecated. Our main dependency
cryptography
deprecated 2.6 in version 0.9 (2015-05-14) with no time table for actually dropping it. pyOpenSSL will drop Python 2.6 support oncecryptography
does.
Changes:¶
- Fixed
OpenSSL.SSL.Context.set_session_id
,OpenSSL.SSL.Connection.renegotiate
,OpenSSL.SSL.Connection.renegotiate_pending
, andOpenSSL.SSL.Context.load_client_ca
. They were lacking an implementation since 0.14. #422 - Fixed segmentation fault when using keys larger than 4096-bit to sign data. #428
- Fixed
AttributeError
whenOpenSSL.SSL.Connection.get_app_data()
was called before setting any app data. #304 - Added
OpenSSL.crypto.dump_publickey()
to dumpOpenSSL.crypto.PKey
objects that represent public keys, andOpenSSL.crypto.load_publickey()
to load such objects from serialized representations. #382 - Added
OpenSSL.crypto.dump_crl()
to dump a certificate revocation list out to a string buffer. #368 - Added
OpenSSL.SSL.Connection.get_state_string()
using the OpenSSL bindingstate_string_long
. #358 - Added support for the
socket.MSG_PEEK
flag toOpenSSL.SSL.Connection.recv()
andOpenSSL.SSL.Connection.recv_into()
. #294 - Added
OpenSSL.SSL.Connection.get_protocol_version()
andOpenSSL.SSL.Connection.get_protocol_version_name()
. #244 - Switched to
utf8string
mask by default. OpenSSL formerly defaulted to aT61String
if there were UTF-8 characters present. This was changed to default toUTF8String
in the config around 2005, but the actual code didn’t change it until late last year. This will default us to the setting that actually works. To revert this you can callOpenSSL.crypto._lib.ASN1_STRING_set_default_mask_asc(b"default")
. #234
Older Changelog Entries¶
The changes from before release 16.0.0 are preserved in the repository.