CHANGELOG.rst

Changelog

37.0.0 - main

Note

This version is not yet released and is under active development.

• BACKWARDS INCOMPATIBLE: Dropped support for LibreSSL 2.9.x and 3.0.x. The new minimum LibreSSL version is 3.1+.
• BACKWARDS INCOMPATIBLE: Removed signer and verifier methods from the public key and private key classes. These methods were originally deprecated in version 2.0, but had an extended deprecation timeline due to usage. Any remaining users should transition to sign and verify.
• Deprecated OpenSSL 1.1.0 support. OpenSSL 1.1.0 is no longer supported by the OpenSSL project. Support for compiling with OpenSSL 1.1.0 will be removed in a future release.
• Added limited support for distinguished names containing a bit string.
• We now ship universal2 wheels on macOS, which contain both arm64 and x86_64 architectures. Users on macOS should upgrade to the latest pip to ensure they can use this wheel, although we will continue to ship x86_64 specific wheels for now to ease the transition.
• Added support for multiple SINGLERESP messages in one OCSP response.

36.0.1 - 2021-12-14

• Updated Windows, macOS, and Linux wheels to be compiled with OpenSSL 1.1.1m.

36.0.0 - 2021-11-21

• FINAL DEPRECATION Support for verifier and signer on our asymmetric key classes was deprecated in version 2.0. These functions had an extended deprecation due to usage, however the next version of cryptography will drop support. Users should migrate to sign and verify.

• The entire :doc:`/x509/index` layer is now written in Rust. This allows alternate asymmetric key implementations that can support cloud key management services or hardware security modules provided they implement the necessary interface (for example: :class:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePrivateKey`).

• :ref:`Deprecated the backend argument<faq-missing-backend>` for all functions.

• Added support for :class:`~cryptography.hazmat.primitives.ciphers.aead.AESOCB3`.

• Added support for iterating over arbitrary request :attr:`~cryptography.x509.CertificateSigningRequest.attributes`.

• Deprecated the get_attribute_for_oid method on :class:`~cryptography.x509.CertificateSigningRequest` in favor of :meth:`~cryptography.x509.Attributes.get_attribute_for_oid` on the new :class:`~cryptography.x509.Attributes` object.

• Fixed handling of PEM files to allow loading when certificate and key are in the same file.

• Fixed parsing of :class:`~cryptography.x509.CertificatePolicies` extensions containing legacy BMPString values in their explicitText.

• Allow parsing of negative serial numbers in certificates. Negative serial numbers are prohibited by RFC 5280 so a deprecation warning will be raised whenever they are encountered. A future version of cryptography will drop support for parsing them.

• Added support for parsing PKCS12 files with friendly names for all certificates with :func:`~cryptography.hazmat.primitives.serialization.pkcs12.load_pkcs12`, which will return an object of type :class:`~cryptography.hazmat.primitives.serialization.pkcs12.PKCS12KeyAndCertificates`.

• :meth:`~cryptography.x509.Name.rfc4514_string` and related methods now have an optional attr_name_overrides parameter to supply custom OID to name mappings, which can be used to match vendor-specific extensions.

• BACKWARDS INCOMPATIBLE: Reverted the nonstandard formatting of email address fields as E in :meth:`~cryptography.x509.Name.rfc4514_string` methods from version 35.0.

  The previous behavior can be restored with: name.rfc4514_string({NameOID.EMAIL_ADDRESS: "E"})

• Allow :class:`~cryptography.hazmat.primitives.asymmetric.x25519.X25519PublicKey` and :class:`~cryptography.hazmat.primitives.asymmetric.x448.X448PublicKey` to be used as public keys when parsing certificates or creating them with :class:`~cryptography.x509.CertificateBuilder`. These key types must be signed with a different signing algorithm as X25519 and X448 do not support signing.

• Extension values can now be serialized to a DER byte string by calling :func:`~cryptography.x509.ExtensionType.public_bytes`.

• Added experimental support for compiling against BoringSSL. As BoringSSL does not commit to a stable API, cryptography tests against the latest commit only. Please note that several features are not available when building against BoringSSL.

• Parsing CertificateSigningRequest from DER and PEM now, for a limited time period, allows the Extension critical field to be incorrectly encoded. See the issue for complete details. This will be reverted in a future cryptography release.

• When :class:`~cryptography.x509.OCSPNonce` are parsed and generated their value is now correctly wrapped in an ASN.1 OCTET STRING. This conforms to RFC 6960 but conflicts with the original behavior specified in RFC 2560. For a temporary period for backwards compatibility, we will also parse values that are encoded as specified in RFC 2560 but this behavior will be removed in a future release.

35.0.0 - 2021-09-29

• Changed the :ref:`version scheme <api-stability:versioning>`. This will result in us incrementing the major version more frequently, but does not change our existing backwards compatibility policy.
• BACKWARDS INCOMPATIBLE: The :doc:`/x509/index` PEM parsers now require that the PEM string passed have PEM delimiters of the correct type. For example, parsing a private key PEM concatenated with a certificate PEM will no longer be accepted by the PEM certificate parser.
• BACKWARDS INCOMPATIBLE: The X.509 certificate parser no longer allows negative serial numbers. RFC 5280 has always prohibited these.
• BACKWARDS INCOMPATIBLE: Additional forms of invalid ASN.1 found during :doc:`/x509/index` parsing will raise an error on initial parse rather than when the malformed field is accessed.
• Rust is now required for building cryptography, the CRYPTOGRAPHY_DONT_BUILD_RUST environment variable is no longer respected.
• Parsers for :doc:`/x509/index` no longer use OpenSSL and have been rewritten in Rust. This should be backwards compatible (modulo the items listed above) and improve both security and performance.
• Added support for OpenSSL 3.0.0 as a compilation target.
• Added support for :class:`~cryptography.hazmat.primitives.hashes.SM3` and :class:`~cryptography.hazmat.primitives.ciphers.algorithms.SM4`, when using OpenSSL 1.1.1. These algorithms are provided for compatibility in regions where they may be required, and are not generally recommended.
• We now ship manylinux_2_24 and musllinux_1_1 wheels, in addition to our manylinux2010 and manylinux2014 wheels. Users on distributions like Alpine Linux should ensure they upgrade to the latest pip to correctly receive wheels.
• Added rfc4514_attribute_name attribute to :attr:`x509.NameAttribute <cryptography.x509.NameAttribute.rfc4514_attribute_name>`.
• Added :class:`~cryptography.hazmat.primitives.kdf.kbkdf.KBKDFCMAC`.

3.4.8 - 2021-08-24

• Updated Windows, macOS, and manylinux wheels to be compiled with OpenSSL 1.1.1l.

3.4.7 - 2021-03-25

• Updated Windows, macOS, and manylinux wheels to be compiled with OpenSSL 1.1.1k.

3.4.6 - 2021-02-16

• Updated Windows, macOS, and manylinux wheels to be compiled with OpenSSL 1.1.1j.

3.4.5 - 2021-02-13

• Various improvements to type hints.
• Lower the minimum supported Rust version (MSRV) to >=1.41.0. This change improves compatibility with system-provided Rust on several Linux distributions.
• cryptography will be switching to a new versioning scheme with its next feature release. More information is available in our :doc:`/api-stability` documentation.

3.4.4 - 2021-02-09

• Added a py.typed file so that mypy will know to use our type annotations.
• Fixed an import cycle that could be triggered by certain import sequences.

3.4.3 - 2021-02-08

• Specify our supported Rust version (>=1.45.0) in our setup.py so users on older versions will get a clear error message.

3.4.2 - 2021-02-08

• Improvements to make the rust transition a bit easier. This includes some better error messages and small dependency fixes. If you experience installation problems Be sure to update pip first, then check the :doc:`FAQ </faq>`.

3.4.1 - 2021-02-07

• Fixed a circular import issue.
• Added additional debug output to assist users seeing installation errors due to outdated pip or missing rustc.

3.4 - 2021-02-07

• BACKWARDS INCOMPATIBLE: Support for Python 2 has been removed.
• We now ship manylinux2014 wheels and no longer ship manylinux1 wheels. Users should upgrade to the latest pip to ensure this doesn't cause issues downloading wheels on their platform.
• cryptography now incorporates Rust code. Users building cryptography themselves will need to have the Rust toolchain installed. Users who use an officially produced wheel will not need to make any changes. The minimum supported Rust version is 1.45.0.
• cryptography now has PEP 484 type hints on nearly all of of its public APIs. Users can begin using them to type check their code with mypy.

3.3.2 - 2021-02-07

• SECURITY ISSUE: Fixed a bug where certain sequences of update() calls when symmetrically encrypting very large payloads (>2GB) could result in an integer overflow, leading to buffer overflows. CVE-2020-36242 Update: This fix is a workaround for CVE-2021-23840 in OpenSSL, fixed in OpenSSL 1.1.1j.

3.3.1 - 2020-12-09

• Re-added a legacy symbol causing problems for older pyOpenSSL users.

3.3 - 2020-12-08

• BACKWARDS INCOMPATIBLE: Support for Python 3.5 has been removed due to low usage and maintenance burden.
• BACKWARDS INCOMPATIBLE: The :class:`~cryptography.hazmat.primitives.ciphers.modes.GCM` and :class:`~cryptography.hazmat.primitives.ciphers.aead.AESGCM` now require 64-bit to 1024-bit (8 byte to 128 byte) initialization vectors. This change is to conform with an upcoming OpenSSL release that will no longer support sizes outside this window.
• BACKWARDS INCOMPATIBLE: When deserializing asymmetric keys we now raise ValueError rather than UnsupportedAlgorithm when an unsupported cipher is used. This change is to conform with an upcoming OpenSSL release that will no longer distinguish between error types.
• BACKWARDS INCOMPATIBLE: We no longer allow loading of finite field Diffie-Hellman parameters of less than 512 bits in length. This change is to conform with an upcoming OpenSSL release that no longer supports smaller sizes. These keys were already wildly insecure and should not have been used in any application outside of testing.
• Updated Windows, macOS, and manylinux wheels to be compiled with OpenSSL 1.1.1i.
• Python 2 support is deprecated in cryptography. This is the last release that will support Python 2.
• Added the :meth:`~cryptography.hazmat.primitives.asymmetric.rsa.RSAPublicKey.recover_data_from_signature` function to :class:`~cryptography.hazmat.primitives.asymmetric.rsa.RSAPublicKey` for recovering the signed data from an RSA signature.

3.2.1 - 2020-10-27

• Disable blinding on RSA public keys to address an error with some versions of OpenSSL.

3.2 - 2020-10-25

• SECURITY ISSUE: Attempted to make RSA PKCS#1v1.5 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`.

3.1.1 - 2020-09-22

• Updated Windows, macOS, and manylinux wheels to be compiled with OpenSSL 1.1.1h.

3.1 - 2020-08-26

• 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 2³¹ bytes no longer raises an OverflowError. This also resolves the same issue in :doc:`/fernet`.

3.0 - 2020-07-20

• 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 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`.

2.9.2 - 2020-04-22

• Updated the macOS wheel to fix an issue where it would not run on macOS versions older than 10.15.

2.9.1 - 2020-04-21

• Updated Windows, macOS, and manylinux wheels to be compiled with OpenSSL 1.1.1g.

2.9 - 2020-04-02

• 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.

2.8 - 2019-10-16

• 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.

2.7 - 2019-05-30

• 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.

2.6.1 - 2019-02-27

• Resolved an error in our build infrastructure that broke our Python3 wheels for macOS and Linux.

2.6 - 2019-02-27

• 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.

2.5 - 2019-01-22

• 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`.

2.4.2 - 2018-11-21

• Updated Windows, macOS, and manylinux1 wheels to be compiled with OpenSSL 1.1.0j.

2.4.1 - 2018-11-11

• Fixed a build breakage in our manylinux1 wheels.

2.4 - 2018-11-11

• 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`.

2.3.1 - 2018-08-14

• Updated Windows, macOS, and manylinux1 wheels to be compiled with OpenSSL 1.1.0i.

2.3 - 2018-07-18

• 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.

2.2.2 - 2018-03-27

• Updated Windows, macOS, and manylinux1 wheels to be compiled with OpenSSL 1.1.0h.

2.2.1 - 2018-03-20

• 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.

2.2 - 2018-03-19

• 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.

2.1.4 - 2017-11-29

• Added X509_up_ref for an upcoming pyOpenSSL release.

2.1.3 - 2017-11-02

• Updated Windows, macOS, and manylinux1 wheels to be compiled with OpenSSL 1.1.0g.

2.1.2 - 2017-10-24

• Corrected a bug with the manylinux1 wheels where OpenSSL's stack was marked executable.

2.1.1 - 2017-10-12

• Fixed support for install with the system pip on Ubuntu 16.04.

2.1 - 2017-10-11

• 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.

2.0.3 - 2017-08-03

• Fixed an issue with weak linking symbols when compiling on macOS versions older than 10.12.

2.0.2 - 2017-07-27

• Marked all symbols as hidden in the manylinux1 wheel to avoid a bug with symbol resolution in certain scenarios.

2.0.1 - 2017-07-26

• 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.

2.0 - 2017-07-17

• 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.

1.9 - 2017-05-29

• 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.

1.8.2 - 2017-05-26

• Fixed a compilation bug affecting OpenSSL 1.1.0f.
• Updated Windows and macOS wheels to be compiled against OpenSSL 1.1.0f.

1.8.1 - 2017-03-10

• Fixed macOS wheels to properly link against 1.1.0 rather than 1.0.2.

1.8 - 2017-03-09

• 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.DHPrivateKey.private_bytes` to :class:`~cryptography.hazmat.primitives.asymmetric.dh.DHPrivateKey`.
• 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`.

1.7.2 - 2017-01-27

• Updated Windows and macOS wheels to be compiled against OpenSSL 1.0.2k.

1.7.1 - 2016-12-13

• Fixed a regression in int_from_bytes where it failed to accept bytearray.

1.7 - 2016-12-12

• 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.

1.6 - 2016-11-22

• 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.

1.5.3 - 2016-11-05

• 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

1.5.2 - 2016-09-26

• Updated Windows and OS X wheels to be compiled against OpenSSL 1.0.2j.

1.5.1 - 2016-09-22

• 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.

1.5 - 2016-08-26

• 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.

1.4 - 2016-06-04

• 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`.

1.3.4 - 2016-06-03

• Added another OpenSSL function to the bindings to support an upcoming pyOpenSSL release.

1.3.3 - 2016-06-02

• Added two new OpenSSL functions to the bindings to support an upcoming pyOpenSSL release.

1.3.2 - 2016-05-04

• 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.

1.3.1 - 2016-03-21

• Fixed a bug that caused an AttributeError when using mock to patch some cryptography modules.

1.3 - 2016-03-18

• 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`.

1.2.3 - 2016-03-01

• Updated Windows and OS X wheels to be compiled against OpenSSL 1.0.2g.

1.2.2 - 2016-01-29

• Updated Windows and OS X wheels to be compiled against OpenSSL 1.0.2f.

1.2.1 - 2016-01-08

• Reverts a change to an OpenSSL EVP_PKEY object that caused errors with pyOpenSSL.

1.2 - 2016-01-08

• 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.

1.1.2 - 2015-12-10

• 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.

1.1.1 - 2015-11-19

• 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.

1.1 - 2015-10-28

• 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.

1.0.2 - 2015-09-27

• 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.

1.0.1 - 2015-09-05

• 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+.

1.0 - 2015-08-12

• 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`.

0.9.3 - 2015-07-09

• Updated Windows wheels to be compiled against OpenSSL 1.0.2d.

0.9.2 - 2015-07-04

• Updated Windows wheels to be compiled against OpenSSL 1.0.2c.

0.9.1 - 2015-06-06

• 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.

0.9 - 2015-05-13

• 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.

0.8.2 - 2015-04-10

• Fixed a race condition when initializing the OpenSSL or CommonCrypto backends in a multi-threaded scenario.

0.8.1 - 2015-03-20

• Updated Windows wheels to be compiled against OpenSSL 1.0.2a.

0.8 - 2015-03-08

• :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.EllipticCurvePrivateKey.private_bytes` to :class:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePrivateKey`.
• Added :class:`~cryptography.hazmat.primitives.asymmetric.rsa.RSAPrivateKeyWithSerialization` and deprecated RSAPrivateKeyWithNumbers.
• Added :meth:`~cryptography.hazmat.primitives.asymmetric.rsa.RSAPrivateKey.private_bytes` to :class:`~cryptography.hazmat.primitives.asymmetric.rsa.RSAPrivateKey`.
• Added :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateKeyWithSerialization` and deprecated DSAPrivateKeyWithNumbers.
• Added :meth:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateKey.private_bytes` to :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateKey`.
• 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`, 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`.

0.7.2 - 2015-01-16

• 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.

0.7.1 - 2014-12-28

• Fixed an issue preventing compilation on platforms where OPENSSL_NO_SSL3 was defined.

0.7 - 2014-12-17

• 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.

0.6.1 - 2014-10-15

• 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.

0.6 - 2014-09-29

• 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 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.

0.5.4 - 2014-08-20

• Added several functions to the OpenSSL bindings to support new functionality in pyOpenSSL.
• Fixed a redefined constant causing compilation failure with Solaris 11.2.

0.5.3 - 2014-08-06

• Updated Windows wheels to be compiled against OpenSSL 1.0.1i.

0.5.2 - 2014-07-09

• Add TraditionalOpenSSLSerializationBackend support to multibackend.
• Fix compilation error on OS X 10.8 (Mountain Lion).

0.5.1 - 2014-07-07

• Add PKCS8SerializationBackend support to multibackend.

0.5 - 2014-07-07

• 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 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 openssl.
• Added :doc:`/hazmat/primitives/asymmetric/ec` and EllipticCurveBackend.
• Added :class:`~cryptography.hazmat.primitives.ciphers.modes.ECB` support for :class:`~cryptography.hazmat.primitives.ciphers.algorithms.TripleDES` on commoncrypto and 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 RSABackend.
• Deprecated create_dsa_signature_ctx and create_dsa_verification_ctx on DSABackend.

0.4 - 2014-05-03

• 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`.

0.3 - 2014-03-27

• 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.

0.2.2 - 2014-03-03

• Removed a constant definition that was causing compilation problems with specific versions of OpenSSL.

0.2.1 - 2014-02-22

• Fix a bug where importing cryptography from multiple paths could cause initialization to fail.

0.2 - 2014-02-20

• Added commoncrypto.
• Added initial commoncrypto.
• Removed register_cipher_adapter method from 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 openssl to the OS random engine.
• Added :class:`~cryptography.hazmat.primitives.ciphers.algorithms.CAST5` (CAST-128) support.

0.1 - 2014-01-08

• Initial release.