Changelogs » Cryptography

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Cryptography

3.3

~~~~~~~~~~~~~~~
  
  .. note:: This version is not yet released and is under active development.
  
  .. _v3-2:

3.2 not secure

~~~~~~~~~~~~~~~~
  
  * **SECURITY ISSUE:** Attempted to make RSA PKCS1v1.5 decryption more constant
  time, to protect against Bleichenbacher vulnerabilities. Due to limitations
  imposed by our API, we cannot completely mitigate this vulnerability and a
  future release will contain a new API which is designed to be resilient to
  these for contexts where it is required. Credit to **Hubert Kario** for
  reporting the issue. *CVE-2020-25659*
  * Support for OpenSSL 1.0.2 has been removed. Users on older version of OpenSSL
  will need to upgrade.
  * Added basic support for PKCS7 signing (including SMIME) via
  :class:`~cryptography.hazmat.primitives.serialization.pkcs7.PKCS7SignatureBuilder`.
  
  .. _v3-1-1:

3.1.1 not secure

~~~~~~~~~~~~~~~~~~
  
  * Updated Windows, macOS, and ``manylinux`` wheels to be compiled with
  OpenSSL 1.1.1h.
  
  .. _v3-1:

3.1 not secure

~~~~~~~~~~~~~~~~
  
  * **BACKWARDS INCOMPATIBLE:** Removed support for ``idna`` based
  :term:`U-label` parsing in various X.509 classes. This support was originally
  deprecated in version 2.1 and moved to an extra in 2.5.
  * Deprecated OpenSSL 1.0.2 support. OpenSSL 1.0.2 is no longer supported by
  the OpenSSL project. The next version of ``cryptography`` will drop support
  for it.
  * Deprecated support for Python 3.5. This version sees very little use and will
  be removed in the next release.
  * ``backend`` arguments to functions are no longer required and the
  default backend will automatically be selected if no ``backend`` is provided.
  * Added initial support for parsing certificates from PKCS7 files with
  :func:`~cryptography.hazmat.primitives.serialization.pkcs7.load_pem_pkcs7_certificates`
  and
  :func:`~cryptography.hazmat.primitives.serialization.pkcs7.load_der_pkcs7_certificates`
  .
  * Calling ``update`` or ``update_into`` on
  :class:`~cryptography.hazmat.primitives.ciphers.CipherContext` with ``data``
  longer than 2\ :sup:`31` bytes no longer raises an ``OverflowError``. This
  also resolves the same issue in :doc:`/fernet`.
  
  .. _v3-0:

3.0 not secure

~~~~~~~~~~~~~~~~
  
  * **BACKWARDS INCOMPATIBLE:** Removed support for passing an
  :class:`~cryptography.x509.Extension` instance to
  :meth:`~cryptography.x509.AuthorityKeyIdentifier.from_issuer_subject_key_identifier`,
  as per our deprecation policy.
  * **BACKWARDS INCOMPATIBLE:** Support for LibreSSL 2.7.x, 2.8.x, and 2.9.0 has
  been removed (2.9.1+ is still supported).
  * **BACKWARDS INCOMPATIBLE:** Dropped support for macOS 10.9, macOS users must
  upgrade to 10.10 or newer.
  * **BACKWARDS INCOMPATIBLE:** RSA
  :meth:`~cryptography.hazmat.primitives.asymmetric.rsa.generate_private_key`
  no longer accepts ``public_exponent`` values except 65537 and 3 (the latter
  for legacy purposes).
  * **BACKWARDS INCOMPATIBLE:** X.509 certificate parsing now enforces that the
  ``version`` field contains a valid value, rather than deferring this check
  until :attr:`~cryptography.x509.Certificate.version` is accessed.
  * Deprecated support for Python 2. At the time there is no time table for
  actually dropping support, however we strongly encourage all users to upgrade
  their Python, as Python 2 no longer receives support from the Python core
  team.
  
  If you have trouble suppressing this warning in tests view the :ref:`FAQ
  entry addressing this issue <faq-howto-handle-deprecation-warning>`.
  
  * Added support for ``OpenSSH`` serialization format for
  ``ec``, ``ed25519``, ``rsa`` and ``dsa`` private keys:
  :func:`~cryptography.hazmat.primitives.serialization.load_ssh_private_key`
  for loading and
  :attr:`~cryptography.hazmat.primitives.serialization.PrivateFormat.OpenSSH`
  for writing.
  * Added support for ``OpenSSH`` certificates to
  :func:`~cryptography.hazmat.primitives.serialization.load_ssh_public_key`.
  * Added :meth:`~cryptography.fernet.Fernet.encrypt_at_time` and
  :meth:`~cryptography.fernet.Fernet.decrypt_at_time` to
  :class:`~cryptography.fernet.Fernet`.
  * Added support for the :class:`~cryptography.x509.SubjectInformationAccess`
  X.509 extension.
  * Added support for parsing
  :class:`~cryptography.x509.SignedCertificateTimestamps` in OCSP responses.
  * Added support for parsing attributes in certificate signing requests via
  :meth:`~cryptography.x509.CertificateSigningRequest.get_attribute_for_oid`.
  * Added support for encoding attributes in certificate signing requests via
  :meth:`~cryptography.x509.CertificateSigningRequestBuilder.add_attribute`.
  * On OpenSSL 1.1.1d and higher ``cryptography`` now uses OpenSSL's
  built-in CSPRNG instead of its own OS random engine because these versions of
  OpenSSL properly reseed on fork.
  * Added initial support for creating PKCS12 files with
  :func:`~cryptography.hazmat.primitives.serialization.pkcs12.serialize_key_and_certificates`.
  
  .. _v2-9-2:

2.9.2 not secure

~~~~~~~~~~~~~~~~~~
  
  * Updated the macOS wheel to fix an issue where it would not run on macOS
  versions older than 10.15.
  
  .. _v2-9-1:

2.9.1 not secure

~~~~~~~~~~~~~~~~~~
  
  * Updated Windows, macOS, and ``manylinux`` wheels to be compiled with
  OpenSSL 1.1.1g.
  
  .. _v2-9:

2.9 not secure

~~~~~~~~~~~~~~~~
  
  * **BACKWARDS INCOMPATIBLE:** Support for Python 3.4 has been removed due to
  low usage and maintenance burden.
  * **BACKWARDS INCOMPATIBLE:** Support for OpenSSL 1.0.1 has been removed.
  Users on older version of OpenSSL will need to upgrade.
  * **BACKWARDS INCOMPATIBLE:** Support for LibreSSL 2.6.x has been removed.
  * Removed support for calling
  :meth:`~cryptography.hazmat.primitives.asymmetric.x25519.X25519PublicKey.public_bytes`
  with no arguments, as per our deprecation policy. You must now pass
  ``encoding`` and ``format``.
  * **BACKWARDS INCOMPATIBLE:** Reversed the order in which
  :meth:`~cryptography.x509.Name.rfc4514_string` returns the RDNs
  as required by :rfc:`4514`.
  * Updated Windows, macOS, and ``manylinux`` wheels to be compiled with
  OpenSSL 1.1.1f.
  * Added support for parsing
  :attr:`~cryptography.x509.ocsp.OCSPResponse.single_extensions` in an OCSP
  response.
  * :class:`~cryptography.x509.NameAttribute` values can now be empty strings.
  
  .. _v2-8:

2.8 not secure

~~~~~~~~~~~~~~~~
  
  * Updated Windows, macOS, and ``manylinux`` wheels to be compiled with
  OpenSSL 1.1.1d.
  * Added support for Python 3.8.
  * Added class methods
  :meth:`Poly1305.generate_tag
  <cryptography.hazmat.primitives.poly1305.Poly1305.generate_tag>`
  and
  :meth:`Poly1305.verify_tag
  <cryptography.hazmat.primitives.poly1305.Poly1305.verify_tag>`
  for Poly1305 sign and verify operations.
  * Deprecated support for OpenSSL 1.0.1. Support will be removed in
  ``cryptography`` 2.9.
  * We now ship ``manylinux2010`` wheels in addition to our ``manylinux1``
  wheels.
  * Added support for ``ed25519`` and ``ed448`` keys in the
  :class:`~cryptography.x509.CertificateBuilder`,
  :class:`~cryptography.x509.CertificateSigningRequestBuilder`,
  :class:`~cryptography.x509.CertificateRevocationListBuilder` and
  :class:`~cryptography.x509.ocsp.OCSPResponseBuilder`.
  * ``cryptography`` no longer depends on ``asn1crypto``.
  * :class:`~cryptography.x509.FreshestCRL` is now allowed as a
  :class:`~cryptography.x509.CertificateRevocationList` extension.
  
  .. _v2-7:

2.7 not secure

~~~~~~~~~~~~~~~~
  
  * **BACKWARDS INCOMPATIBLE:** We no longer distribute 32-bit ``manylinux1``
  wheels. Continuing to produce them was a maintenance burden.
  * **BACKWARDS INCOMPATIBLE:** Removed the
  ``cryptography.hazmat.primitives.mac.MACContext`` interface. The ``CMAC`` and
  ``HMAC`` APIs have not changed, but they are no longer registered as
  ``MACContext`` instances.
  * Updated Windows, macOS, and ``manylinux1`` wheels to be compiled with
  OpenSSL 1.1.1c.
  * Removed support for running our tests with ``setup.py test``. Users
  interested in running our tests can continue to follow the directions in our
  :doc:`development documentation</development/getting-started>`.
  * Add support for :class:`~cryptography.hazmat.primitives.poly1305.Poly1305`
  when using OpenSSL 1.1.1 or newer.
  * Support serialization with ``Encoding.OpenSSH`` and ``PublicFormat.OpenSSH``
  in
  :meth:`Ed25519PublicKey.public_bytes
  <cryptography.hazmat.primitives.asymmetric.ed25519.Ed25519PublicKey.public_bytes>`
  .
  * Correctly allow passing a ``SubjectKeyIdentifier`` to
  :meth:`~cryptography.x509.AuthorityKeyIdentifier.from_issuer_subject_key_identifier`
  and deprecate passing an ``Extension`` object. The documentation always
  required ``SubjectKeyIdentifier`` but the implementation previously
  required an ``Extension``.
  
  .. _v2-6-1:

2.6.1 not secure

~~~~~~~~~~~~~~~~~~
  
  * Resolved an error in our build infrastructure that broke our Python3 wheels
  for macOS and Linux.
  
  .. _v2-6:

2.6 not secure

~~~~~~~~~~~~~~~~
  
  * **BACKWARDS INCOMPATIBLE:** Removed
  ``cryptography.hazmat.primitives.asymmetric.utils.encode_rfc6979_signature``
  and
  ``cryptography.hazmat.primitives.asymmetric.utils.decode_rfc6979_signature``,
  which had been deprecated for nearly 4 years. Use
  :func:`~cryptography.hazmat.primitives.asymmetric.utils.encode_dss_signature`
  and
  :func:`~cryptography.hazmat.primitives.asymmetric.utils.decode_dss_signature`
  instead.
  * **BACKWARDS INCOMPATIBLE**: Removed ``cryptography.x509.Certificate.serial``,
  which had been deprecated for nearly 3 years. Use
  :attr:`~cryptography.x509.Certificate.serial_number` instead.
  * Updated Windows, macOS, and ``manylinux1`` wheels to be compiled with
  OpenSSL 1.1.1b.
  * Added support for :doc:`/hazmat/primitives/asymmetric/ed448` when using
  OpenSSL 1.1.1b or newer.
  * Added support for :doc:`/hazmat/primitives/asymmetric/ed25519` when using
  OpenSSL 1.1.1b or newer.
  * :func:`~cryptography.hazmat.primitives.serialization.load_ssh_public_key` can
  now load ``ed25519`` public keys.
  * Add support for easily mapping an object identifier to its elliptic curve
  class via
  :func:`~cryptography.hazmat.primitives.asymmetric.ec.get_curve_for_oid`.
  * Add support for OpenSSL when compiled with the ``no-engine``
  (``OPENSSL_NO_ENGINE``) flag.
  
  .. _v2-5:

2.5 not secure

~~~~~~~~~~~~~~~~
  
  * **BACKWARDS INCOMPATIBLE:** :term:`U-label` strings were deprecated in
  version 2.1, but this version removes the default ``idna`` dependency as
  well. If you still need this deprecated path please install cryptography
  with the ``idna`` extra: ``pip install cryptography[idna]``.
  * **BACKWARDS INCOMPATIBLE:** The minimum supported PyPy version is now 5.4.
  * Numerous classes and functions have been updated to allow :term:`bytes-like`
  types for keying material and passwords, including symmetric algorithms, AEAD
  ciphers, KDFs, loading asymmetric keys, and one time password classes.
  * Updated Windows, macOS, and ``manylinux1`` wheels to be compiled with
  OpenSSL 1.1.1a.
  * Added support for :class:`~cryptography.hazmat.primitives.hashes.SHA512_224`
  and :class:`~cryptography.hazmat.primitives.hashes.SHA512_256` when using
  OpenSSL 1.1.1.
  * Added support for :class:`~cryptography.hazmat.primitives.hashes.SHA3_224`,
  :class:`~cryptography.hazmat.primitives.hashes.SHA3_256`,
  :class:`~cryptography.hazmat.primitives.hashes.SHA3_384`, and
  :class:`~cryptography.hazmat.primitives.hashes.SHA3_512` when using OpenSSL
  1.1.1.
  * Added support for :doc:`/hazmat/primitives/asymmetric/x448` when using
  OpenSSL 1.1.1.
  * Added support for :class:`~cryptography.hazmat.primitives.hashes.SHAKE128`
  and :class:`~cryptography.hazmat.primitives.hashes.SHAKE256` when using
  OpenSSL 1.1.1.
  * Added initial support for parsing PKCS12 files with
  :func:`~cryptography.hazmat.primitives.serialization.pkcs12.load_key_and_certificates`.
  * Added support for :class:`~cryptography.x509.IssuingDistributionPoint`.
  * Added ``rfc4514_string()`` method to
  :meth:`x509.Name <cryptography.x509.Name.rfc4514_string>`,
  :meth:`x509.RelativeDistinguishedName
  <cryptography.x509.RelativeDistinguishedName.rfc4514_string>`, and
  :meth:`x509.NameAttribute <cryptography.x509.NameAttribute.rfc4514_string>`
  to format the name or component an :rfc:`4514` Distinguished Name string.
  * Added
  :meth:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePublicKey.from_encoded_point`,
  which immediately checks if the point is on the curve and supports compressed
  points. Deprecated the previous method
  :meth:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePublicNumbers.from_encoded_point`.
  * Added :attr:`~cryptography.x509.ocsp.OCSPResponse.signature_hash_algorithm`
  to ``OCSPResponse``.
  * Updated :doc:`/hazmat/primitives/asymmetric/x25519` support to allow
  additional serialization methods. Calling
  :meth:`~cryptography.hazmat.primitives.asymmetric.x25519.X25519PublicKey.public_bytes`
  with no arguments has been deprecated.
  * Added support for encoding compressed and uncompressed points via
  :meth:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePublicKey.public_bytes`. Deprecated the previous method
  :meth:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePublicNumbers.encode_point`.
  
  
  .. _v2-4-2:

2.4.2 not secure

~~~~~~~~~~~~~~~~~~
  
  * Updated Windows, macOS, and ``manylinux1`` wheels to be compiled with
  OpenSSL 1.1.0j.
  
  .. _v2-4-1:

2.4.1 not secure

~~~~~~~~~~~~~~~~~~
  
  * Fixed a build breakage in our ``manylinux1`` wheels.
  
  .. _v2-4:

2.4 not secure

~~~~~~~~~~~~~~~~
  
  * **BACKWARDS INCOMPATIBLE:** Dropped support for LibreSSL 2.4.x.
  * Deprecated OpenSSL 1.0.1 support. OpenSSL 1.0.1 is no longer supported by
  the OpenSSL project. At this time there is no time table for dropping
  support, however we strongly encourage all users to upgrade or install
  ``cryptography`` from a wheel.
  * Added initial :doc:`OCSP </x509/ocsp>` support.
  * Added support for :class:`~cryptography.x509.PrecertPoison`.
  
  .. _v2-3-1:

2.3.1 not secure

~~~~~~~~~~~~~~~~~~
  
  * Updated Windows, macOS, and ``manylinux1`` wheels to be compiled with
  OpenSSL 1.1.0i.
  
  .. _v2-3:

2.3 not secure

~~~~~~~~~~~~~~~~
  
  * **SECURITY ISSUE:**
  :meth:`~cryptography.hazmat.primitives.ciphers.AEADDecryptionContext.finalize_with_tag`
  allowed tag truncation by default which can allow tag forgery in some cases.
  The method now enforces the ``min_tag_length`` provided to the
  :class:`~cryptography.hazmat.primitives.ciphers.modes.GCM` constructor.
  *CVE-2018-10903*
  * Added support for Python 3.7.
  * Added :meth:`~cryptography.fernet.Fernet.extract_timestamp` to get the
  authenticated timestamp of a :doc:`Fernet </fernet>` token.
  * Support for Python 2.7.x without ``hmac.compare_digest`` has been deprecated.
  We will require Python 2.7.7 or higher (or 2.7.6 on Ubuntu) in the next
  ``cryptography`` release.
  * Fixed multiple issues preventing ``cryptography`` from compiling against
  LibreSSL 2.7.x.
  * Added
  :class:`~cryptography.x509.CertificateRevocationList.get_revoked_certificate_by_serial_number`
  for quick serial number searches in CRLs.
  * The :class:`~cryptography.x509.RelativeDistinguishedName` class now
  preserves the order of attributes. Duplicate attributes now raise an error
  instead of silently discarding duplicates.
  * :func:`~cryptography.hazmat.primitives.keywrap.aes_key_unwrap` and
  :func:`~cryptography.hazmat.primitives.keywrap.aes_key_unwrap_with_padding`
  now raise :class:`~cryptography.hazmat.primitives.keywrap.InvalidUnwrap` if
  the wrapped key is an invalid length, instead of ``ValueError``.
  
  .. _v2-2-2:

2.2.2 not secure

~~~~~~~~~~~~~~~~~~
  
  * Updated Windows, macOS, and ``manylinux1`` wheels to be compiled with
  OpenSSL 1.1.0h.
  
  .. _v2-2-1:

2.2.1 not secure

~~~~~~~~~~~~~~~~~~
  
  * Reverted a change to ``GeneralNames`` which prohibited having zero elements,
  due to breakages.
  * Fixed a bug in
  :func:`~cryptography.hazmat.primitives.keywrap.aes_key_unwrap_with_padding`
  that caused it to raise ``InvalidUnwrap`` when key length modulo 8 was
  zero.
  
  
  .. _v2-2:

2.2 not secure

~~~~~~~~~~~~~~~~
  
  * **BACKWARDS INCOMPATIBLE:** Support for Python 2.6 has been dropped.
  * Resolved a bug in ``HKDF`` that incorrectly constrained output size.
  * Added :class:`~cryptography.hazmat.primitives.asymmetric.ec.BrainpoolP256R1`,
  :class:`~cryptography.hazmat.primitives.asymmetric.ec.BrainpoolP384R1`, and
  :class:`~cryptography.hazmat.primitives.asymmetric.ec.BrainpoolP512R1` to
  support inter-operating with systems like German smart meters.
  * Added token rotation support to :doc:`Fernet </fernet>` with
  :meth:`~cryptography.fernet.MultiFernet.rotate`.
  * Fixed a memory leak in
  :func:`~cryptography.hazmat.primitives.asymmetric.ec.derive_private_key`.
  * Added support for AES key wrapping with padding via
  :func:`~cryptography.hazmat.primitives.keywrap.aes_key_wrap_with_padding`
  and
  :func:`~cryptography.hazmat.primitives.keywrap.aes_key_unwrap_with_padding`
  .
  * Allow loading DSA keys with 224 bit ``q``.
  
  .. _v2-1-4:

2.1.4 not secure

~~~~~~~~~~~~~~~~~~
  
  * Added ``X509_up_ref`` for an upcoming ``pyOpenSSL`` release.
  
  .. _v2-1-3:

2.1.3 not secure

~~~~~~~~~~~~~~~~~~
  
  * Updated Windows, macOS, and ``manylinux1`` wheels to be compiled with
  OpenSSL 1.1.0g.
  
  .. _v2-1-2:

2.1.2 not secure

~~~~~~~~~~~~~~~~~~
  
  * Corrected a bug with the ``manylinux1`` wheels where OpenSSL's stack was
  marked executable.
  
  .. _v2-1-1:

2.1.1 not secure

~~~~~~~~~~~~~~~~~~
  
  * Fixed support for install with the system ``pip`` on Ubuntu 16.04.
  
  .. _v2-1:

2.1 not secure

~~~~~~~~~~~~~~~~
  
  * **FINAL DEPRECATION** Python 2.6 support is deprecated, and will be removed
  in the next release of ``cryptography``.
  * **BACKWARDS INCOMPATIBLE:** ``Whirlpool``, ``RIPEMD160``, and
  ``UnsupportedExtension`` have been removed in accordance with our
  :doc:`/api-stability` policy.
  * **BACKWARDS INCOMPATIBLE:**
  :attr:`DNSName.value <cryptography.x509.DNSName.value>`,
  :attr:`RFC822Name.value <cryptography.x509.RFC822Name.value>`, and
  :attr:`UniformResourceIdentifier.value
  <cryptography.x509.UniformResourceIdentifier.value>`
  will now return an :term:`A-label` string when parsing a certificate
  containing an internationalized domain name (IDN) or if the caller passed
  a :term:`U-label` to the constructor. See below for additional deprecations
  related to this change.
  * Installing ``cryptography`` now requires ``pip`` 6 or newer.
  * Deprecated passing :term:`U-label` strings to the
  :class:`~cryptography.x509.DNSName`,
  :class:`~cryptography.x509.UniformResourceIdentifier`, and
  :class:`~cryptography.x509.RFC822Name` constructors. Instead, users should
  pass values as :term:`A-label` strings with ``idna`` encoding if necessary.
  This change will not affect anyone who is not processing internationalized
  domains.
  * Added support for
  :class:`~cryptography.hazmat.primitives.ciphers.algorithms.ChaCha20`. In
  most cases users should choose
  :class:`~cryptography.hazmat.primitives.ciphers.aead.ChaCha20Poly1305`
  rather than using this unauthenticated form.
  * Added :meth:`~cryptography.x509.CertificateRevocationList.is_signature_valid`
  to :class:`~cryptography.x509.CertificateRevocationList`.
  * Support :class:`~cryptography.hazmat.primitives.hashes.BLAKE2b` and
  :class:`~cryptography.hazmat.primitives.hashes.BLAKE2s` with
  :class:`~cryptography.hazmat.primitives.hmac.HMAC`.
  * Added support for
  :class:`~cryptography.hazmat.primitives.ciphers.modes.XTS` mode for
  AES.
  * Added support for using labels with
  :class:`~cryptography.hazmat.primitives.asymmetric.padding.OAEP` when using
  OpenSSL 1.0.2 or greater.
  * Improved compatibility with NSS when issuing certificates from an issuer
  that has a subject with non-``UTF8String`` string types.
  * Add support for the :class:`~cryptography.x509.DeltaCRLIndicator` extension.
  * Add support for the :class:`~cryptography.x509.TLSFeature`
  extension. This is commonly used for enabling ``OCSP Must-Staple`` in
  certificates.
  * Add support for the :class:`~cryptography.x509.FreshestCRL` extension.
  
  .. _v2-0-3:

2.0.3 not secure

~~~~~~~~~~~~~~~~~~
  
  * Fixed an issue with weak linking symbols when compiling on macOS
  versions older than 10.12.
  
  
  .. _v2-0-2:

2.0.2 not secure

~~~~~~~~~~~~~~~~~~
  
  * Marked all symbols as hidden in the ``manylinux1`` wheel to avoid a
  bug with symbol resolution in certain scenarios.
  
  
  .. _v2-0-1:

2.0.1 not secure

~~~~~~~~~~~~~~~~~~
  
  * Fixed a compilation bug affecting OpenBSD.
  * Altered the ``manylinux1`` wheels to statically link OpenSSL instead of
  dynamically linking and bundling the shared object. This should resolve
  crashes seen when using ``uwsgi`` or other binaries that link against
  OpenSSL independently.
  * Fixed the stack level for the ``signer`` and ``verifier`` warnings.
  
  
  .. _v2-0:

2.0 not secure

~~~~~~~~~~~~~~~~
  
  * **BACKWARDS INCOMPATIBLE:** Support for Python 3.3 has been dropped.
  * We now ship ``manylinux1`` wheels linked against OpenSSL 1.1.0f. These wheels
  will be automatically used with most Linux distributions if you are running
  the latest pip.
  * Deprecated the use of ``signer`` on
  :class:`~cryptography.hazmat.primitives.asymmetric.rsa.RSAPrivateKey`,
  :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateKey`,
  and
  :class:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePrivateKey`
  in favor of ``sign``.
  * Deprecated the use of ``verifier`` on
  :class:`~cryptography.hazmat.primitives.asymmetric.rsa.RSAPublicKey`,
  :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPublicKey`,
  and
  :class:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePublicKey`
  in favor of ``verify``.
  * Added support for parsing
  :class:`~cryptography.x509.certificate_transparency.SignedCertificateTimestamp`
  objects from X.509 certificate extensions.
  * Added support for
  :class:`~cryptography.hazmat.primitives.ciphers.aead.ChaCha20Poly1305`.
  * Added support for
  :class:`~cryptography.hazmat.primitives.ciphers.aead.AESCCM`.
  * Added
  :class:`~cryptography.hazmat.primitives.ciphers.aead.AESGCM`, a "one shot"
  API for AES GCM encryption.
  * Added support for :doc:`/hazmat/primitives/asymmetric/x25519`.
  * Added support for serializing and deserializing Diffie-Hellman parameters
  with
  :func:`~cryptography.hazmat.primitives.serialization.load_pem_parameters`,
  :func:`~cryptography.hazmat.primitives.serialization.load_der_parameters`,
  and
  :meth:`~cryptography.hazmat.primitives.asymmetric.dh.DHParameters.parameter_bytes`
  .
  * The ``extensions`` attribute on :class:`~cryptography.x509.Certificate`,
  :class:`~cryptography.x509.CertificateSigningRequest`,
  :class:`~cryptography.x509.CertificateRevocationList`, and
  :class:`~cryptography.x509.RevokedCertificate` now caches the computed
  ``Extensions`` object. There should be no performance change, just a
  performance improvement for programs accessing the ``extensions`` attribute
  multiple times.
  
  
  .. _v1-9:

1.9 not secure

~~~~~~~~~~~~~~~~
  
  * **BACKWARDS INCOMPATIBLE:** Elliptic Curve signature verification no longer
  returns ``True`` on success. This brings it in line with the interface's
  documentation, and our intent. The correct way to use
  :meth:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePublicKey.verify`
  has always been to check whether or not
  :class:`~cryptography.exceptions.InvalidSignature` was raised.
  * **BACKWARDS INCOMPATIBLE:** Dropped support for macOS 10.7 and 10.8.
  * **BACKWARDS INCOMPATIBLE:** The minimum supported PyPy version is now 5.3.
  * Python 3.3 support has been deprecated, and will be removed in the next
  ``cryptography`` release.
  * Add support for providing ``tag`` during
  :class:`~cryptography.hazmat.primitives.ciphers.modes.GCM` finalization via
  :meth:`~cryptography.hazmat.primitives.ciphers.AEADDecryptionContext.finalize_with_tag`.
  * Fixed an issue preventing ``cryptography`` from compiling against
  LibreSSL 2.5.x.
  * Added
  :meth:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePublicKey.key_size`
  and
  :meth:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePrivateKey.key_size`
  as convenience methods for determining the bit size of a secret scalar for
  the curve.
  * Accessing an unrecognized extension marked critical on an X.509 object will
  no longer raise an ``UnsupportedExtension`` exception, instead an
  :class:`~cryptography.x509.UnrecognizedExtension` object will be returned.
  This behavior was based on a poor reading of the RFC, unknown critical
  extensions only need to be rejected on certificate verification.
  * The CommonCrypto backend has been removed.
  * MultiBackend has been removed.
  * ``Whirlpool`` and ``RIPEMD160`` have been deprecated.
  
  
  .. _v1-8-2:

1.8.2 not secure

~~~~~~~~~~~~~~~~~~
  
  * Fixed a compilation bug affecting OpenSSL 1.1.0f.
  * Updated Windows and macOS wheels to be compiled against OpenSSL 1.1.0f.
  
  
  .. _v1-8-1:

1.8.1 not secure

~~~~~~~~~~~~~~~~~~
  
  * Fixed macOS wheels to properly link against 1.1.0 rather than 1.0.2.
  
  
  .. _v1-8:

1.8 not secure

~~~~~~~~~~~~~~~~
  
  * Added support for Python 3.6.
  * Windows and macOS wheels now link against OpenSSL 1.1.0.
  * macOS wheels are no longer universal. This change significantly shrinks the
  size of the wheels. Users on macOS 32-bit Python (if there are any) should
  migrate to 64-bit or build their own packages.
  * Changed ASN.1 dependency from ``pyasn1`` to ``asn1crypto`` resulting in a
  general performance increase when encoding/decoding ASN.1 structures. Also,
  the ``pyasn1_modules`` test dependency is no longer required.
  * Added support for
  :meth:`~cryptography.hazmat.primitives.ciphers.CipherContext.update_into` on
  :class:`~cryptography.hazmat.primitives.ciphers.CipherContext`.
  * Added
  :meth:`~cryptography.hazmat.primitives.asymmetric.dh.DHPrivateKeyWithSerialization.private_bytes`
  to
  :class:`~cryptography.hazmat.primitives.asymmetric.dh.DHPrivateKeyWithSerialization`.
  * Added
  :meth:`~cryptography.hazmat.primitives.asymmetric.dh.DHPublicKey.public_bytes`
  to
  :class:`~cryptography.hazmat.primitives.asymmetric.dh.DHPublicKey`.
  * :func:`~cryptography.hazmat.primitives.serialization.load_pem_private_key`
  and
  :func:`~cryptography.hazmat.primitives.serialization.load_der_private_key`
  now require that ``password`` must be bytes if provided. Previously this
  was documented but not enforced.
  * Added support for subgroup order in :doc:`/hazmat/primitives/asymmetric/dh`.
  
  
  .. _v1-7-2:

1.7.2 not secure

~~~~~~~~~~~~~~~~~~
  
  * Updated Windows and macOS wheels to be compiled against OpenSSL 1.0.2k.
  
  
  .. _v1-7-1:

1.7.1 not secure

~~~~~~~~~~~~~~~~~~
  
  * Fixed a regression in ``int_from_bytes`` where it failed to accept
  ``bytearray``.
  
  
  .. _v1-7:

1.7 not secure

~~~~~~~~~~~~~~~~
  
  * Support for OpenSSL 1.0.0 has been removed. Users on older version of OpenSSL
  will need to upgrade.
  * Added support for Diffie-Hellman key exchange using
  :meth:`~cryptography.hazmat.primitives.asymmetric.dh.DHPrivateKey.exchange`.
  * The OS random engine for OpenSSL has been rewritten to improve compatibility
  with embedded Python and other edge cases. More information about this change
  can be found in the
  `pull request <https://github.com/pyca/cryptography/pull/3229>`_.
  
  
  .. _v1-6:

1.6 not secure

~~~~~~~~~~~~~~~~
  
  * Deprecated support for OpenSSL 1.0.0. Support will be removed in
  ``cryptography`` 1.7.
  * Replaced the Python-based OpenSSL locking callbacks with a C version to fix
  a potential deadlock that could occur if a garbage collection cycle occurred
  while inside the lock.
  * Added support for :class:`~cryptography.hazmat.primitives.hashes.BLAKE2b` and
  :class:`~cryptography.hazmat.primitives.hashes.BLAKE2s` when using OpenSSL
  1.1.0.
  * Added
  :attr:`~cryptography.x509.Certificate.signature_algorithm_oid` support to
  :class:`~cryptography.x509.Certificate`.
  * Added
  :attr:`~cryptography.x509.CertificateSigningRequest.signature_algorithm_oid`
  support to :class:`~cryptography.x509.CertificateSigningRequest`.
  * Added
  :attr:`~cryptography.x509.CertificateRevocationList.signature_algorithm_oid`
  support to :class:`~cryptography.x509.CertificateRevocationList`.
  * Added support for :class:`~cryptography.hazmat.primitives.kdf.scrypt.Scrypt`
  when using OpenSSL 1.1.0.
  * Added a workaround to improve compatibility with Python application bundling
  tools like ``PyInstaller`` and ``cx_freeze``.
  * Added support for generating a
  :meth:`~cryptography.x509.random_serial_number`.
  * Added support for encoding ``IPv4Network`` and ``IPv6Network`` in X.509
  certificates for use with :class:`~cryptography.x509.NameConstraints`.
  * Added :meth:`~cryptography.x509.Name.public_bytes` to
  :class:`~cryptography.x509.Name`.
  * Added :class:`~cryptography.x509.RelativeDistinguishedName`
  * :class:`~cryptography.x509.DistributionPoint` now accepts
  :class:`~cryptography.x509.RelativeDistinguishedName` for
  :attr:`~cryptography.x509.DistributionPoint.relative_name`.
  Deprecated use of :class:`~cryptography.x509.Name` as
  :attr:`~cryptography.x509.DistributionPoint.relative_name`.
  * :class:`~cryptography.x509.Name` now accepts an iterable of
  :class:`~cryptography.x509.RelativeDistinguishedName`.  RDNs can
  be accessed via the :attr:`~cryptography.x509.Name.rdns`
  attribute.  When constructed with an iterable of
  :class:`~cryptography.x509.NameAttribute`, each attribute becomes
  a single-valued RDN.
  * Added
  :func:`~cryptography.hazmat.primitives.asymmetric.ec.derive_private_key`.
  * Added support for signing and verifying RSA, DSA, and ECDSA signatures with
  :class:`~cryptography.hazmat.primitives.asymmetric.utils.Prehashed`
  digests.
  
  
  .. _v1-5-3:

1.5.3 not secure

~~~~~~~~~~~~~~~~~~
  
  * **SECURITY ISSUE**: Fixed a bug where ``HKDF`` would return an empty
  byte-string if used with a ``length`` less than ``algorithm.digest_size``.
  Credit to **Markus Döring** for reporting the issue. *CVE-2016-9243*
  
  
  .. _v1-5-2:

1.5.2 not secure

~~~~~~~~~~~~~~~~~~
  
  * Updated Windows and OS X wheels to be compiled against OpenSSL 1.0.2j.
  
  
  .. _v1-5-1:

1.5.1 not secure

~~~~~~~~~~~~~~~~~~
  
  * Updated Windows and OS X wheels to be compiled against OpenSSL 1.0.2i.
  * Resolved a ``UserWarning`` when used with cffi 1.8.3.
  * Fixed a memory leak in name creation with X.509.
  * Added a workaround for old versions of setuptools.
  * Fixed an issue preventing ``cryptography`` from compiling against
  OpenSSL 1.0.2i.
  
  
  
  .. _v1-5:

1.5 not secure

~~~~~~~~~~~~~~~~
  
  * Added
  :func:`~cryptography.hazmat.primitives.asymmetric.padding.calculate_max_pss_salt_length`.
  * Added "one shot"
  :meth:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateKey.sign`
  and
  :meth:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPublicKey.verify`
  methods to DSA keys.
  * Added "one shot"
  :meth:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePrivateKey.sign`
  and
  :meth:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePublicKey.verify`
  methods to ECDSA keys.
  * Switched back to the older callback model on Python 3.5 in order to mitigate
  the locking callback problem with OpenSSL <1.1.0.
  * :class:`~cryptography.x509.CertificateBuilder`,
  :class:`~cryptography.x509.CertificateRevocationListBuilder`, and
  :class:`~cryptography.x509.RevokedCertificateBuilder` now accept timezone
  aware ``datetime`` objects as method arguments
  * ``cryptography`` now supports OpenSSL 1.1.0 as a compilation target.
  
  
  
  .. _v1-4:

1.4 not secure

~~~~~~~~~~~~~~~~
  
  * Support for OpenSSL 0.9.8 has been removed. Users on older versions of
  OpenSSL will need to upgrade.
  * Added :class:`~cryptography.hazmat.primitives.kdf.kbkdf.KBKDFHMAC`.
  * Added support for ``OpenSSH`` public key serialization.
  * Added support for SHA-2 in RSA
  :class:`~cryptography.hazmat.primitives.asymmetric.padding.OAEP` when using
  OpenSSL 1.0.2 or greater.
  * Added "one shot"
  :meth:`~cryptography.hazmat.primitives.asymmetric.rsa.RSAPrivateKey.sign`
  and
  :meth:`~cryptography.hazmat.primitives.asymmetric.rsa.RSAPublicKey.verify`
  methods to RSA keys.
  * Deprecated the ``serial`` attribute on
  :class:`~cryptography.x509.Certificate`, in favor of
  :attr:`~cryptography.x509.Certificate.serial_number`.
  
  
  
  .. _v1-3-4:

1.3.4 not secure

~~~~~~~~~~~~~~~~~~
  
  * Added another OpenSSL function to the bindings to support an upcoming
  ``pyOpenSSL`` release.
  
  
  
  .. _v1-3-3:

1.3.3 not secure

~~~~~~~~~~~~~~~~~~
  
  * Added two new OpenSSL functions to the bindings to support an upcoming
  ``pyOpenSSL`` release.
  
  
  .. _v1-3-2:

1.3.2 not secure

~~~~~~~~~~~~~~~~~~
  
  * Updated Windows and OS X wheels to be compiled against OpenSSL 1.0.2h.
  * Fixed an issue preventing ``cryptography`` from compiling against
  LibreSSL 2.3.x.
  
  
  .. _v1-3-1:

1.3.1 not secure

~~~~~~~~~~~~~~~~~~
  
  * Fixed a bug that caused an ``AttributeError`` when using ``mock`` to patch
  some ``cryptography`` modules.
  
  
  .. _v1-3:

1.3 not secure

~~~~~~~~~~~~~~~~
  
  * Added support for padding ANSI X.923 with
  :class:`~cryptography.hazmat.primitives.padding.ANSIX923`.
  * Deprecated support for OpenSSL 0.9.8. Support will be removed in
  ``cryptography`` 1.4.
  * Added support for the :class:`~cryptography.x509.PolicyConstraints`
  X.509 extension including both parsing and generation using
  :class:`~cryptography.x509.CertificateBuilder` and
  :class:`~cryptography.x509.CertificateSigningRequestBuilder`.
  * Added :attr:`~cryptography.x509.CertificateSigningRequest.is_signature_valid`
  to :class:`~cryptography.x509.CertificateSigningRequest`.
  * Fixed an intermittent ``AssertionError`` when performing an RSA decryption on
  an invalid ciphertext, ``ValueError`` is now correctly raised in all cases.
  * Added
  :meth:`~cryptography.x509.AuthorityKeyIdentifier.from_issuer_subject_key_identifier`.
  
  
  .. _v1-2-3:

1.2.3 not secure

~~~~~~~~~~~~~~~~~~
  
  * Updated Windows and OS X wheels to be compiled against OpenSSL 1.0.2g.
  
  
  .. _v1-2-2:

1.2.2 not secure

~~~~~~~~~~~~~~~~~~
  
  * Updated Windows and OS X wheels to be compiled against OpenSSL 1.0.2f.
  
  
  .. _v1-2-1:

1.2.1 not secure

~~~~~~~~~~~~~~~~~~
  
  * Reverts a change to an OpenSSL ``EVP_PKEY`` object that caused errors with
  ``pyOpenSSL``.
  
  
  .. _v1-2:

1.2 not secure

~~~~~~~~~~~~~~~~
  
  * **BACKWARDS INCOMPATIBLE:**
  :class:`~cryptography.x509.RevokedCertificate`
  :attr:`~cryptography.x509.RevokedCertificate.extensions` now uses extension
  classes rather than returning raw values inside the
  :class:`~cryptography.x509.Extension`
  :attr:`~cryptography.x509.Extension.value`. The new classes
  are:
  
  * :class:`~cryptography.x509.CertificateIssuer`
  * :class:`~cryptography.x509.CRLReason`
  * :class:`~cryptography.x509.InvalidityDate`
  * Deprecated support for OpenSSL 0.9.8 and 1.0.0. At this time there is no time
  table for actually dropping support, however we strongly encourage all users
  to upgrade, as those versions no longer receive support from the OpenSSL
  project.
  * The :class:`~cryptography.x509.Certificate` class now has
  :attr:`~cryptography.x509.Certificate.signature` and
  :attr:`~cryptography.x509.Certificate.tbs_certificate_bytes` attributes.
  * The :class:`~cryptography.x509.CertificateSigningRequest` class now has
  :attr:`~cryptography.x509.CertificateSigningRequest.signature` and
  :attr:`~cryptography.x509.CertificateSigningRequest.tbs_certrequest_bytes`
  attributes.
  * The :class:`~cryptography.x509.CertificateRevocationList` class now has
  :attr:`~cryptography.x509.CertificateRevocationList.signature` and
  :attr:`~cryptography.x509.CertificateRevocationList.tbs_certlist_bytes`
  attributes.
  * :class:`~cryptography.x509.NameConstraints` are now supported in the
  :class:`~cryptography.x509.CertificateBuilder` and
  :class:`~cryptography.x509.CertificateSigningRequestBuilder`.
  * Support serialization of certificate revocation lists using the
  :meth:`~cryptography.x509.CertificateRevocationList.public_bytes` method of
  :class:`~cryptography.x509.CertificateRevocationList`.
  * Add support for parsing :class:`~cryptography.x509.CertificateRevocationList`
  :meth:`~cryptography.x509.CertificateRevocationList.extensions` in the
  OpenSSL backend. The following extensions are currently supported:
  
  * :class:`~cryptography.x509.AuthorityInformationAccess`
  * :class:`~cryptography.x509.AuthorityKeyIdentifier`
  * :class:`~cryptography.x509.CRLNumber`
  * :class:`~cryptography.x509.IssuerAlternativeName`
  * Added :class:`~cryptography.x509.CertificateRevocationListBuilder` and
  :class:`~cryptography.x509.RevokedCertificateBuilder` to allow creation of
  CRLs.
  * Unrecognized non-critical X.509 extensions are now parsed into an
  :class:`~cryptography.x509.UnrecognizedExtension` object.
  
  
  .. _v1-1-2:

1.1.2 not secure

~~~~~~~~~~~~~~~~~~
  
  * Fixed a SIGBUS crash with the OS X wheels caused by redefinition of a
  method.
  * Fixed a runtime error ``undefined symbol EC_GFp_nistp224_method`` that
  occurred with some OpenSSL installations.
  * Updated Windows and OS X wheels to be compiled against OpenSSL 1.0.2e.
  
  
  .. _v1-1-1:

1.1.1 not secure

~~~~~~~~~~~~~~~~~~
  
  * Fixed several small bugs related to compiling the OpenSSL bindings with
  unusual OpenSSL configurations.
  * Resolved an issue where, depending on the method of installation and
  which Python interpreter they were using, users on El Capitan (OS X 10.11)
  may have seen an ``InternalError`` on import.
  
  
  .. _v1-1:

1.1 not secure

~~~~~~~~~~~~~~~~
  
  * Added support for Elliptic Curve Diffie-Hellman with
  :class:`~cryptography.hazmat.primitives.asymmetric.ec.ECDH`.
  * Added :class:`~cryptography.hazmat.primitives.kdf.x963kdf.X963KDF`.
  * Added support for parsing certificate revocation lists (CRLs) using
  :func:`~cryptography.x509.load_pem_x509_crl` and
  :func:`~cryptography.x509.load_der_x509_crl`.
  * Add support for AES key wrapping with
  :func:`~cryptography.hazmat.primitives.keywrap.aes_key_wrap` and
  :func:`~cryptography.hazmat.primitives.keywrap.aes_key_unwrap`.
  * Added a ``__hash__`` method to :class:`~cryptography.x509.Name`.
  * Add support for encoding and decoding elliptic curve points to a byte string
  form using
  :meth:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePublicNumbers.encode_point`
  and
  :meth:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePublicNumbers.from_encoded_point`.
  * Added :meth:`~cryptography.x509.Extensions.get_extension_for_class`.
  * :class:`~cryptography.x509.CertificatePolicies` are now supported in the
  :class:`~cryptography.x509.CertificateBuilder`.
  * ``countryName`` is now encoded as a ``PrintableString`` when creating subject
  and issuer distinguished names with the Certificate and CSR builder classes.
  
  
  .. _v1-0-2:

1.0.2 not secure

~~~~~~~~~~~~~~~~~~
  * **SECURITY ISSUE**: The OpenSSL backend prior to 1.0.2 made extensive use
  of assertions to check response codes where our tests could not trigger a
  failure.  However, when Python is run with ``-O`` these asserts are optimized
  away.  If a user ran Python with this flag and got an invalid response code
  this could result in undefined behavior or worse. Accordingly, all response
  checks from the OpenSSL backend have been converted from ``assert``
  to a true function call. Credit **Emilia Käsper (Google Security Team)**
  for the report.
  
  
  .. _v1-0-1:

1.0.1 not secure

~~~~~~~~~~~~~~~~~~
  
  * We now ship OS X wheels that statically link OpenSSL by default. When
  installing a wheel on OS X 10.10+ (and using a Python compiled against the
  10.10 SDK) users will no longer need to compile. See :doc:`/installation` for
  alternate installation methods if required.
  * Set the default string mask to UTF-8 in the OpenSSL backend to resolve
  character encoding issues with older versions of OpenSSL.
  * Several new OpenSSL bindings have been added to support a future pyOpenSSL
  release.
  * Raise an error during install on PyPy < 2.6. 1.0+ requires PyPy 2.6+.
  
  
  .. _v1-0:

1.0 not secure

~~~~~~~~~~~~~~~~
  
  * Switched to the new `cffi`_ ``set_source`` out-of-line API mode for
  compilation. This results in significantly faster imports and lowered
  memory consumption. Due to this change we no longer support PyPy releases
  older than 2.6 nor do we support any released version of PyPy3 (until a
  version supporting cffi 1.0 comes out).
  * Fix parsing of OpenSSH public keys that have spaces in comments.
  * Support serialization of certificate signing requests using the
  ``public_bytes`` method of
  :class:`~cryptography.x509.CertificateSigningRequest`.
  * Support serialization of certificates using the ``public_bytes`` method of
  :class:`~cryptography.x509.Certificate`.
  * Add ``get_provisioning_uri`` method to
  :class:`~cryptography.hazmat.primitives.twofactor.hotp.HOTP` and
  :class:`~cryptography.hazmat.primitives.twofactor.totp.TOTP` for generating
  provisioning URIs.
  * Add :class:`~cryptography.hazmat.primitives.kdf.concatkdf.ConcatKDFHash`
  and :class:`~cryptography.hazmat.primitives.kdf.concatkdf.ConcatKDFHMAC`.
  * Raise a ``TypeError`` when passing objects that are not text as the value to
  :class:`~cryptography.x509.NameAttribute`.
  * Add support for :class:`~cryptography.x509.OtherName` as a general name
  type.
  * Added new X.509 extension support in :class:`~cryptography.x509.Certificate`
  The following new extensions are now supported:
  
  * :class:`~cryptography.x509.OCSPNoCheck`
  * :class:`~cryptography.x509.InhibitAnyPolicy`
  * :class:`~cryptography.x509.IssuerAlternativeName`
  * :class:`~cryptography.x509.NameConstraints`
  
  * Extension support was added to
  :class:`~cryptography.x509.CertificateSigningRequest`.
  * Add support for creating signed certificates with
  :class:`~cryptography.x509.CertificateBuilder`. This includes support for
  the following extensions:
  
  * :class:`~cryptography.x509.BasicConstraints`
  * :class:`~cryptography.x509.SubjectAlternativeName`
  * :class:`~cryptography.x509.KeyUsage`
  * :class:`~cryptography.x509.ExtendedKeyUsage`
  * :class:`~cryptography.x509.SubjectKeyIdentifier`
  * :class:`~cryptography.x509.AuthorityKeyIdentifier`
  * :class:`~cryptography.x509.AuthorityInformationAccess`
  * :class:`~cryptography.x509.CRLDistributionPoints`
  * :class:`~cryptography.x509.InhibitAnyPolicy`
  * :class:`~cryptography.x509.IssuerAlternativeName`
  * :class:`~cryptography.x509.OCSPNoCheck`
  
  * Add support for creating certificate signing requests with
  :class:`~cryptography.x509.CertificateSigningRequestBuilder`. This includes
  support for the same extensions supported in the ``CertificateBuilder``.
  * Deprecate ``encode_rfc6979_signature`` and ``decode_rfc6979_signature`` in
  favor of
  :func:`~cryptography.hazmat.primitives.asymmetric.utils.encode_dss_signature`
  and
  :func:`~cryptography.hazmat.primitives.asymmetric.utils.decode_dss_signature`.
  
  
  
  .. _v0-9-3:

0.9.3 not secure

~~~~~~~~~~~~~~~~~~
  
  * Updated Windows wheels to be compiled against OpenSSL 1.0.2d.
  
  
  .. _v0-9-2:

0.9.2 not secure

~~~~~~~~~~~~~~~~~~
  
  * Updated Windows wheels to be compiled against OpenSSL 1.0.2c.
  
  
  .. _v0-9-1:

0.9.1 not secure

~~~~~~~~~~~~~~~~~~
  
  * **SECURITY ISSUE**: Fixed a double free in the OpenSSL backend when using DSA
  to verify signatures. Note that this only affects PyPy 2.6.0 and (presently
  unreleased) CFFI versions greater than 1.1.0.
  
  
  .. _v0-9:

0.9 not secure

~~~~~~~~~~~~~~~~
  
  * Removed support for Python 3.2. This version of Python is rarely used
  and caused support headaches. Users affected by this should upgrade to 3.3+.
  * Deprecated support for Python 2.6. At the time there is no time table for
  actually dropping support, however we strongly encourage all users to upgrade
  their Python, as Python 2.6 no longer receives support from the Python core
  team.
  * Add support for the
  :class:`~cryptography.hazmat.primitives.asymmetric.ec.SECP256K1` elliptic
  curve.
  * Fixed compilation when using an OpenSSL which was compiled with the
  ``no-comp`` (``OPENSSL_NO_COMP``) option.
  * Support :attr:`~cryptography.hazmat.primitives.serialization.Encoding.DER`
  serialization of public keys using the ``public_bytes`` method of
  :class:`~cryptography.hazmat.primitives.asymmetric.rsa.RSAPublicKeyWithSerialization`,
  :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPublicKeyWithSerialization`,
  and
  :class:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePublicKeyWithSerialization`.
  * Support :attr:`~cryptography.hazmat.primitives.serialization.Encoding.DER`
  serialization of private keys using the ``private_bytes`` method of
  :class:`~cryptography.hazmat.primitives.asymmetric.rsa.RSAPrivateKeyWithSerialization`,
  :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateKeyWithSerialization`,
  and
  :class:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePrivateKeyWithSerialization`.
  * Add support for parsing X.509 certificate signing requests (CSRs) with
  :func:`~cryptography.x509.load_pem_x509_csr` and
  :func:`~cryptography.x509.load_der_x509_csr`.
  * Moved ``cryptography.exceptions.InvalidToken`` to
  :class:`cryptography.hazmat.primitives.twofactor.InvalidToken` and deprecated
  the old location. This was moved to minimize confusion between this exception
  and :class:`cryptography.fernet.InvalidToken`.
  * Added support for X.509 extensions in :class:`~cryptography.x509.Certificate`
  objects. The following extensions are supported as of this release:
  
  * :class:`~cryptography.x509.BasicConstraints`
  * :class:`~cryptography.x509.AuthorityKeyIdentifier`
  * :class:`~cryptography.x509.SubjectKeyIdentifier`
  * :class:`~cryptography.x509.KeyUsage`
  * :class:`~cryptography.x509.SubjectAlternativeName`
  * :class:`~cryptography.x509.ExtendedKeyUsage`
  * :class:`~cryptography.x509.CRLDistributionPoints`
  * :class:`~cryptography.x509.AuthorityInformationAccess`
  * :class:`~cryptography.x509.CertificatePolicies`
  
  Note that unsupported extensions with the critical flag raise
  ``UnsupportedExtension`` while unsupported extensions set to non-critical are
  silently ignored. Read the :doc:`X.509 documentation</x509/index>` for more
  information.
  
  
  .. _v0-8-2:

0.8.2 not secure

~~~~~~~~~~~~~~~~~~
  
  * Fixed a race condition when initializing the OpenSSL or CommonCrypto backends
  in a multi-threaded scenario.
  
  
  .. _v0-8-1:

0.8.1 not secure

~~~~~~~~~~~~~~~~~~
  
  * Updated Windows wheels to be compiled against OpenSSL 1.0.2a.
  
  
  .. _v0-8:

0.8 not secure

~~~~~~~~~~~~~~~~
  
  * :func:`~cryptography.hazmat.primitives.serialization.load_ssh_public_key` can
  now load elliptic curve public keys.
  * Added
  :attr:`~cryptography.x509.Certificate.signature_hash_algorithm` support to
  :class:`~cryptography.x509.Certificate`.
  * Added
  :func:`~cryptography.hazmat.primitives.asymmetric.rsa.rsa_recover_prime_factors`
  * :class:`~cryptography.hazmat.primitives.kdf.KeyDerivationFunction` was moved
  from ``cryptography.hazmat.primitives.interfaces`` to
  :mod:`~cryptography.hazmat.primitives.kdf`.
  * Added support for parsing X.509 names. See the
  :doc:`X.509 documentation</x509/index>` for more information.
  * Added
  :func:`~cryptography.hazmat.primitives.serialization.load_der_private_key` to
  support loading of DER encoded private keys and
  :func:`~cryptography.hazmat.primitives.serialization.load_der_public_key` to
  support loading DER encoded public keys.
  * Fixed building against LibreSSL, a compile-time substitute for OpenSSL.
  * FreeBSD 9.2 was removed from the continuous integration system.
  * Updated Windows wheels to be compiled against OpenSSL 1.0.2.
  * :func:`~cryptography.hazmat.primitives.serialization.load_pem_public_key`
  and :func:`~cryptography.hazmat.primitives.serialization.load_der_public_key`
  now support PKCS1 RSA public keys (in addition to the previous support for
  SubjectPublicKeyInfo format for RSA, EC, and DSA).
  * Added
  :class:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePrivateKeyWithSerialization`
  and deprecated ``EllipticCurvePrivateKeyWithNumbers``.
  * Added
  :meth:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePrivateKeyWithSerialization.private_bytes`
  to
  :class:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePrivateKeyWithSerialization`.
  * Added
  :class:`~cryptography.hazmat.primitives.asymmetric.rsa.RSAPrivateKeyWithSerialization`
  and deprecated ``RSAPrivateKeyWithNumbers``.
  * Added
  :meth:`~cryptography.hazmat.primitives.asymmetric.rsa.RSAPrivateKeyWithSerialization.private_bytes`
  to
  :class:`~cryptography.hazmat.primitives.asymmetric.rsa.RSAPrivateKeyWithSerialization`.
  * Added
  :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateKeyWithSerialization`
  and deprecated ``DSAPrivateKeyWithNumbers``.
  * Added
  :meth:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateKeyWithSerialization.private_bytes`
  to
  :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateKeyWithSerialization`.
  * Added
  :class:`~cryptography.hazmat.primitives.asymmetric.rsa.RSAPublicKeyWithSerialization`
  and deprecated ``RSAPublicKeyWithNumbers``.
  * Added ``public_bytes`` to
  :class:`~cryptography.hazmat.primitives.asymmetric.rsa.RSAPublicKeyWithSerialization`.
  * Added
  :class:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePublicKeyWithSerialization`
  and deprecated ``EllipticCurvePublicKeyWithNumbers``.
  * Added ``public_bytes`` to
  :class:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePublicKeyWithSerialization`.
  * Added
  :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPublicKeyWithSerialization`
  and deprecated ``DSAPublicKeyWithNumbers``.
  * Added ``public_bytes`` to
  :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPublicKeyWithSerialization`.
  * :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm` and
  :class:`~cryptography.hazmat.primitives.hashes.HashContext` were moved from
  ``cryptography.hazmat.primitives.interfaces`` to
  :mod:`~cryptography.hazmat.primitives.hashes`.
  * :class:`~cryptography.hazmat.primitives.ciphers.CipherContext`,
  :class:`~cryptography.hazmat.primitives.ciphers.AEADCipherContext`,
  :class:`~cryptography.hazmat.primitives.ciphers.AEADEncryptionContext`,
  :class:`~cryptography.hazmat.primitives.ciphers.CipherAlgorithm`, and
  :class:`~cryptography.hazmat.primitives.ciphers.BlockCipherAlgorithm`
  were moved from ``cryptography.hazmat.primitives.interfaces`` to
  :mod:`~cryptography.hazmat.primitives.ciphers`.
  * :class:`~cryptography.hazmat.primitives.ciphers.modes.Mode`,
  :class:`~cryptography.hazmat.primitives.ciphers.modes.ModeWithInitializationVector`,
  :class:`~cryptography.hazmat.primitives.ciphers.modes.ModeWithNonce`, and
  :class:`~cryptography.hazmat.primitives.ciphers.modes.ModeWithAuthenticationTag`
  were moved from ``cryptography.hazmat.primitives.interfaces`` to
  :mod:`~cryptography.hazmat.primitives.ciphers.modes`.
  * :class:`~cryptography.hazmat.primitives.padding.PaddingContext` was moved
  from ``cryptography.hazmat.primitives.interfaces`` to
  :mod:`~cryptography.hazmat.primitives.padding`.
  *
  :class:`~cryptography.hazmat.primitives.asymmetric.padding.AsymmetricPadding`
  was moved from ``cryptography.hazmat.primitives.interfaces`` to
  :mod:`~cryptography.hazmat.primitives.asymmetric.padding`.
  * ``AsymmetricSignatureContext`` and ``AsymmetricVerificationContext``
  were moved from ``cryptography.hazmat.primitives.interfaces`` to
  ``cryptography.hazmat.primitives.asymmetric``.
  * :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAParameters`,
  :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAParametersWithNumbers`,
  :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateKey`,
  ``DSAPrivateKeyWithNumbers``,
  :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPublicKey` and
  ``DSAPublicKeyWithNumbers`` were moved from
  ``cryptography.hazmat.primitives.interfaces`` to
  :mod:`~cryptography.hazmat.primitives.asymmetric.dsa`
  * :class:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurve`,
  :class:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurveSignatureAlgorithm`,
  :class:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePrivateKey`,
  ``EllipticCurvePrivateKeyWithNumbers``,
  :class:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePublicKey`,
  and ``EllipticCurvePublicKeyWithNumbers``
  were moved from ``cryptography.hazmat.primitives.interfaces`` to
  :mod:`~cryptography.hazmat.primitives.asymmetric.ec`.
  * :class:`~cryptography.hazmat.primitives.asymmetric.rsa.RSAPrivateKey`,
  ``RSAPrivateKeyWithNumbers``,
  :class:`~cryptography.hazmat.primitives.asymmetric.rsa.RSAPublicKey` and
  ``RSAPublicKeyWithNumbers`` were moved from
  ``cryptography.hazmat.primitives.interfaces`` to
  :mod:`~cryptography.hazmat.primitives.asymmetric.rsa`.
  
  
  .. _v0-7-2:

0.7.2 not secure

~~~~~~~~~~~~~~~~~~
  
  * Updated Windows wheels to be compiled against OpenSSL 1.0.1l.
  * ``enum34`` is no longer installed on Python 3.4, where it is included in
  the standard library.
  * Added a new function to the OpenSSL bindings to support additional
  functionality in pyOpenSSL.
  
  
  .. _v0-7-1:

0.7.1 not secure

~~~~~~~~~~~~~~~~~~
  
  * Fixed an issue preventing compilation on platforms where ``OPENSSL_NO_SSL3``
  was defined.
  
  
  .. _v0-7:

0.7 not secure

~~~~~~~~~~~~~~~~
  
  * Cryptography has been relicensed from the Apache Software License, Version
  2.0, to being available under *either* the Apache Software License, Version
  2.0, or the BSD license.
  * Added key-rotation support to :doc:`Fernet </fernet>` with
  :class:`~cryptography.fernet.MultiFernet`.
  * More bit-lengths are now supported for ``p`` and ``q`` when loading DSA keys
  from numbers.
  * Added ``MACContext`` as a common interface for CMAC and HMAC and
  deprecated ``CMACContext``.
  * Added support for encoding and decoding :rfc:`6979` signatures in
  :doc:`/hazmat/primitives/asymmetric/utils`.
  * Added
  :func:`~cryptography.hazmat.primitives.serialization.load_ssh_public_key` to
  support the loading of OpenSSH public keys (:rfc:`4253`). Only RSA and DSA
  keys are currently supported.
  * Added initial support for X.509 certificate parsing. See the
  :doc:`X.509 documentation</x509/index>` for more information.
  
  
  .. _v0-6-1:

0.6.1 not secure

~~~~~~~~~~~~~~~~~~
  
  * Updated Windows wheels to be compiled against OpenSSL 1.0.1j.
  * Fixed an issue where OpenSSL 1.0.1j changed the errors returned by some
  functions.
  * Added our license file to the ``cryptography-vectors`` package.
  * Implemented DSA hash truncation support (per FIPS 186-3) in the OpenSSL
  backend. This works around an issue in 1.0.0, 1.0.0a, and 1.0.0b where
  truncation was not implemented.
  
  
  .. _v0-6:

0.6 not secure

~~~~~~~~~~~~~~~~
  
  * Added
  :func:`~cryptography.hazmat.primitives.serialization.load_pem_private_key` to
  ease loading private keys, and
  :func:`~cryptography.hazmat.primitives.serialization.load_pem_public_key` to
  support loading public keys.
  * Removed the, deprecated in 0.4, support for the ``salt_length`` argument to
  the :class:`~cryptography.hazmat.primitives.asymmetric.padding.MGF1`
  constructor. The ``salt_length`` should be passed to
  :class:`~cryptography.hazmat.primitives.asymmetric.padding.PSS` instead.
  * Fix compilation on OS X Yosemite.
  * Deprecated ``elliptic_curve_private_key_from_numbers`` and
  ``elliptic_curve_public_key_from_numbers`` in favor of
  ``load_elliptic_curve_private_numbers`` and
  ``load_elliptic_curve_public_numbers`` on
  :class:`~cryptography.hazmat.backends.interfaces.EllipticCurveBackend`.
  * Added ``EllipticCurvePrivateKeyWithNumbers`` and
  ``EllipticCurvePublicKeyWithNumbers`` support.
  * Work around three GCM related bugs in CommonCrypto and OpenSSL.
  
  * On the CommonCrypto backend adding AAD but not subsequently calling update
  would return null tag bytes.
  
  * One the CommonCrypto backend a call to update without an empty add AAD call
  would return null ciphertext bytes.
  
  * On the OpenSSL backend with certain versions adding AAD only would give
  invalid tag bytes.
  
  * Support loading EC private keys from PEM.
  
  
  .. _v0-5-4:

0.5.4 not secure

~~~~~~~~~~~~~~~~~~
  
  * Added several functions to the OpenSSL bindings to support new
  functionality in pyOpenSSL.
  * Fixed a redefined constant causing compilation failure with Solaris 11.2.
  
  
  .. _v0-5-3:

0.5.3 not secure

~~~~~~~~~~~~~~~~~~
  
  * Updated Windows wheels to be compiled against OpenSSL 1.0.1i.
  
  
  .. _v0-5-2:

0.5.2 not secure

~~~~~~~~~~~~~~~~~~
  
  * Add ``TraditionalOpenSSLSerializationBackend`` support to ``multibackend``.
  * Fix compilation error on OS X 10.8 (Mountain Lion).
  
  
  .. _v0-5-1:

0.5.1 not secure

~~~~~~~~~~~~~~~~~~
  
  * Add ``PKCS8SerializationBackend`` support to ``multibackend``.
  
  
  .. _v0-5:

0.5 not secure

~~~~~~~~~~~~~~~~
  
  * **BACKWARDS INCOMPATIBLE:**
  :class:`~cryptography.hazmat.primitives.ciphers.modes.GCM` no longer allows
  truncation of tags by default. Previous versions of ``cryptography`` allowed
  tags to be truncated by default, applications wishing to preserve this
  behavior (not recommended) can pass the ``min_tag_length`` argument.
  * Windows builds now statically link OpenSSL by default. When installing a
  wheel on Windows you no longer need to install OpenSSL separately. Windows
  users can switch between static and dynamic linking with an environment
  variable. See :doc:`/installation` for more details.
  * Added :class:`~cryptography.hazmat.primitives.kdf.hkdf.HKDFExpand`.
  * Added :class:`~cryptography.hazmat.primitives.ciphers.modes.CFB8` support
  for :class:`~cryptography.hazmat.primitives.ciphers.algorithms.AES` and
  :class:`~cryptography.hazmat.primitives.ciphers.algorithms.TripleDES` on
  ``commoncrypto`` and :doc:`/hazmat/backends/openssl`.
  * Added ``AES`` :class:`~cryptography.hazmat.primitives.ciphers.modes.CTR`
  support to the OpenSSL backend when linked against 0.9.8.
  * Added ``PKCS8SerializationBackend`` and
  ``TraditionalOpenSSLSerializationBackend`` support to the
  :doc:`/hazmat/backends/openssl`.
  * Added :doc:`/hazmat/primitives/asymmetric/ec` and
  :class:`~cryptography.hazmat.backends.interfaces.EllipticCurveBackend`.
  * Added :class:`~cryptography.hazmat.primitives.ciphers.modes.ECB` support
  for :class:`~cryptography.hazmat.primitives.ciphers.algorithms.TripleDES` on
  ``commoncrypto`` and :doc:`/hazmat/backends/openssl`.
  * Deprecated the concrete ``RSAPrivateKey`` class in favor of backend
  specific providers of the
  :class:`cryptography.hazmat.primitives.asymmetric.rsa.RSAPrivateKey`
  interface.
  * Deprecated the concrete ``RSAPublicKey`` in favor of backend specific
  providers of the
  :class:`cryptography.hazmat.primitives.asymmetric.rsa.RSAPublicKey`
  interface.
  * Deprecated the concrete ``DSAPrivateKey`` class in favor of backend
  specific providers of the
  :class:`cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateKey`
  interface.
  * Deprecated the concrete ``DSAPublicKey`` class in favor of backend specific
  providers of the
  :class:`cryptography.hazmat.primitives.asymmetric.dsa.DSAPublicKey`
  interface.
  * Deprecated the concrete ``DSAParameters`` class in favor of backend specific
  providers of the
  :class:`cryptography.hazmat.primitives.asymmetric.dsa.DSAParameters`
  interface.
  * Deprecated ``encrypt_rsa``, ``decrypt_rsa``, ``create_rsa_signature_ctx`` and
  ``create_rsa_verification_ctx`` on
  :class:`~cryptography.hazmat.backends.interfaces.RSABackend`.
  * Deprecated ``create_dsa_signature_ctx`` and ``create_dsa_verification_ctx``
  on :class:`~cryptography.hazmat.backends.interfaces.DSABackend`.
  
  
  .. _v0-4:

0.4 not secure

~~~~~~~~~~~~~~~~
  
  * Deprecated ``salt_length`` on
  :class:`~cryptography.hazmat.primitives.asymmetric.padding.MGF1` and added it
  to :class:`~cryptography.hazmat.primitives.asymmetric.padding.PSS`. It will
  be removed from ``MGF1`` in two releases per our :doc:`/api-stability`
  policy.
  * Added :class:`~cryptography.hazmat.primitives.ciphers.algorithms.SEED`
  support.
  * Added :class:`~cryptography.hazmat.primitives.cmac.CMAC`.
  * Added decryption support to
  :class:`~cryptography.hazmat.primitives.asymmetric.rsa.RSAPrivateKey`
  and encryption support to
  :class:`~cryptography.hazmat.primitives.asymmetric.rsa.RSAPublicKey`.
  * Added signature support to
  :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateKey`
  and verification support to
  :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPublicKey`.
  
  
  .. _v0-3:

0.3 not secure

~~~~~~~~~~~~~~~~
  
  * Added :class:`~cryptography.hazmat.primitives.twofactor.hotp.HOTP`.
  * Added :class:`~cryptography.hazmat.primitives.twofactor.totp.TOTP`.
  * Added :class:`~cryptography.hazmat.primitives.ciphers.algorithms.IDEA`
  support.
  * Added signature support to
  :class:`~cryptography.hazmat.primitives.asymmetric.rsa.RSAPrivateKey`
  and verification support to
  :class:`~cryptography.hazmat.primitives.asymmetric.rsa.RSAPublicKey`.
  * Moved test vectors to the new ``cryptography_vectors`` package.
  
  
  .. _v0-2-2:

0.2.2 not secure

~~~~~~~~~~~~~~~~~~
  
  * Removed a constant definition that was causing compilation problems with
  specific versions of OpenSSL.
  
  
  .. _v0-2-1:

0.2.1 not secure

~~~~~~~~~~~~~~~~~~
  
  * Fix a bug where importing cryptography from multiple paths could cause
  initialization to fail.
  
  
  .. _v0-2:

0.2 not secure

~~~~~~~~~~~~~~~~
  
  * Added ``commoncrypto``.
  * Added initial ``commoncrypto``.
  * Removed ``register_cipher_adapter`` method from
  :class:`~cryptography.hazmat.backends.interfaces.CipherBackend`.
  * Added support for the OpenSSL backend under Windows.
  * Improved thread-safety for the OpenSSL backend.
  * Fixed compilation on systems where OpenSSL's ``ec.h`` header is not
  available, such as CentOS.
  * Added :class:`~cryptography.hazmat.primitives.kdf.pbkdf2.PBKDF2HMAC`.
  * Added :class:`~cryptography.hazmat.primitives.kdf.hkdf.HKDF`.
  * Added ``multibackend``.
  * Set default random for the :doc:`/hazmat/backends/openssl` to the OS
  random engine.
  * Added :class:`~cryptography.hazmat.primitives.ciphers.algorithms.CAST5`
  (CAST-128) support.
  
  
  .. _v0-1:

0.1 not secure

~~~~~~~~~~~~~~~~
  
  * Initial release.
  
  .. _`master`: https://github.com/pyca/cryptography/
  .. _`cffi`: https://cffi.readthedocs.io/