deprecate backend part 4 of n (#6522)

9 files changed, 41 insertions, 204 deletions

diff --git a/docs/development/reviewing-patches.rst b/docs/development/reviewing-patches.rst
index d3d66482a..98df23d90 100644
--- a/docs/development/reviewing-patches.rst
+++ b/docs/development/reviewing-patches.rst
@@ -16,7 +16,7 @@ Intent
 Architecture
 ------------
 
-* Is the proposed change being made in the correct place? Is it a fix in a
+* Is the proposed change being made in the correct place? Is it a fix in the
   backend when it should be in the primitives?
 
 Implementation
diff --git a/docs/development/submitting-patches.rst b/docs/development/submitting-patches.rst
index e6f8abc65..6c03bce2c 100644
--- a/docs/development/submitting-patches.rst
+++ b/docs/development/submitting-patches.rst
@@ -75,10 +75,6 @@ Every recipe should include a version or algorithmic marker of some sort in its
 output in order to allow transparent upgrading of the algorithms in use, as
 the algorithms or parameters needed to achieve a given security margin evolve.
 
-APIs at the :doc:`/hazmat/primitives/index` and recipes layer should
-automatically use the :func:`~cryptography.hazmat.backends.default_backend`,
-but optionally allow specifying a different backend.
-
 C bindings
 ~~~~~~~~~~
 
diff --git a/docs/hazmat/primitives/cryptographic-hashes.rst b/docs/hazmat/primitives/cryptographic-hashes.rst
index a11399251..46b96bdd2 100644
--- a/docs/hazmat/primitives/cryptographic-hashes.rst
+++ b/docs/hazmat/primitives/cryptographic-hashes.rst
@@ -5,7 +5,7 @@ Message digests (Hashing)
 
 .. module:: cryptography.hazmat.primitives.hashes
 
-.. class:: Hash(algorithm, backend=None)
+.. class:: Hash(algorithm)
 
     A cryptographic hash function takes an arbitrary block of data and
     calculates a fixed-size bit string (a digest), such that different data
@@ -27,10 +27,6 @@ Message digests (Hashing)
         >>> digest.finalize()
         b'l\xa1=R\xcap\xc8\x83\xe0\xf0\xbb\x10\x1eBZ\x89\xe8bM\xe5\x1d\xb2\xd29%\x93\xafj\x84\x11\x80\x90'
 
-    If the backend doesn't support the requested ``algorithm`` an
-    :class:`~cryptography.exceptions.UnsupportedAlgorithm` exception will be
-    raised.
-
     Keep in mind that attacks against cryptographic hashes only get stronger
     with time, and that often algorithms that were once thought to be strong,
     become broken. Because of this it's important to include a plan for
@@ -41,13 +37,9 @@ Message digests (Hashing)
         :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm`
         instance such as those described in
         :ref:`below <cryptographic-hash-algorithms>`.
-    :param backend: An optional
-        :class:`~cryptography.hazmat.backends.interfaces.HashBackend`
-        instance.
 
     :raises cryptography.exceptions.UnsupportedAlgorithm: This is raised if the
-        provided ``backend`` does not implement
-        :class:`~cryptography.hazmat.backends.interfaces.HashBackend`
+        provided ``algorithm`` is unsupported.
 
     .. method:: update(data)
 
diff --git a/docs/hazmat/primitives/key-derivation-functions.rst b/docs/hazmat/primitives/key-derivation-functions.rst
index 0ec4eccb5..1d9aba56f 100644
--- a/docs/hazmat/primitives/key-derivation-functions.rst
+++ b/docs/hazmat/primitives/key-derivation-functions.rst
@@ -36,7 +36,7 @@ PBKDF2
 
 .. currentmodule:: cryptography.hazmat.primitives.kdf.pbkdf2
 
-.. class:: PBKDF2HMAC(algorithm, length, salt, iterations, backend=None)
+.. class:: PBKDF2HMAC(algorithm, length, salt, iterations)
 
     .. versionadded:: 0.2
 
@@ -85,12 +85,6 @@ PBKDF2
         takes. Higher numbers help mitigate brute force attacks against derived
         keys. A `more detailed description`_ can be consulted for additional
         information.
-    :param backend: An optional instance of
-        :class:`~cryptography.hazmat.backends.interfaces.PBKDF2HMACBackend`.
-
-    :raises cryptography.exceptions.UnsupportedAlgorithm: This is raised if the
-        provided ``backend`` does not implement
-        :class:`~cryptography.hazmat.backends.interfaces.PBKDF2HMACBackend`
 
     :raises TypeError: This exception is raised if ``salt`` is not ``bytes``.
 
@@ -139,7 +133,7 @@ Scrypt
 
 .. currentmodule:: cryptography.hazmat.primitives.kdf.scrypt
 
-.. class:: Scrypt(salt, length, n, r, p, backend=None)
+.. class:: Scrypt(salt, length, n, r, p)
 
     .. versionadded:: 1.6
 
@@ -181,8 +175,6 @@ Scrypt
         power of 2.
     :param int r: Block size parameter.
     :param int p: Parallelization parameter.
-    :param backend: An optional instance of
-        :class:`~cryptography.hazmat.backends.interfaces.ScryptBackend`.
 
     The computational and memory cost of Scrypt can be adjusted by manipulating
     the 3 parameters: ``n``, ``r``, and ``p``. In general, the memory cost of
@@ -196,9 +188,8 @@ Scrypt
     minimum value of ``n=2**14`` for interactive logins (t < 100ms), or
     ``n=2**20`` for more sensitive files (t < 5s).
 
-    :raises cryptography.exceptions.UnsupportedAlgorithm: This is raised if the
-        provided ``backend`` does not implement
-        :class:`~cryptography.hazmat.backends.interfaces.ScryptBackend`
+    :raises cryptography.exceptions.UnsupportedAlgorithm: If Scrypt is not
+        supported by the OpenSSL version ``cryptography`` is using.
 
     :raises TypeError: This exception is raised if ``salt`` is not ``bytes``.
     :raises ValueError: This exception is raised if ``n`` is less than 2, if
@@ -251,7 +242,7 @@ ConcatKDF
 
 .. currentmodule:: cryptography.hazmat.primitives.kdf.concatkdf
 
-.. class:: ConcatKDFHash(algorithm, length, otherinfo, backend=None)
+.. class:: ConcatKDFHash(algorithm, length, otherinfo)
 
     .. versionadded:: 1.0
 
@@ -291,13 +282,6 @@ ConcatKDF
     :param bytes otherinfo: Application specific context information.
         If ``None`` is explicitly passed an empty byte string will be used.
 
-    :param backend: An optional instance of
-        :class:`~cryptography.hazmat.backends.interfaces.HashBackend`.
-
-    :raises cryptography.exceptions.UnsupportedAlgorithm: This is raised
-        if the provided ``backend`` does not implement
-        :class:`~cryptography.hazmat.backends.interfaces.HashBackend`
-
     :raises TypeError: This exception is raised if ``otherinfo`` is not
         ``bytes``.
 
@@ -337,7 +321,7 @@ ConcatKDF
         raises an exception if they do not match.
 
 
-.. class:: ConcatKDFHMAC(algorithm, length, salt, otherinfo, backend=None)
+.. class:: ConcatKDFHMAC(algorithm, length, salt, otherinfo)
 
     .. versionadded:: 1.0
 
@@ -386,13 +370,6 @@ ConcatKDF
     :param bytes otherinfo: Application specific context information.
         If ``None`` is explicitly passed an empty byte string will be used.
 
-    :param backend: An optional instance of
-        :class:`~cryptography.hazmat.backends.interfaces.HMACBackend`.
-
-    :raises cryptography.exceptions.UnsupportedAlgorithm: This is raised if the
-        provided ``backend`` does not implement
-        :class:`~cryptography.hazmat.backends.interfaces.HMACBackend`
-
     :raises TypeError: This exception is raised if ``salt`` or ``otherinfo``
         is not ``bytes``.
 
@@ -436,7 +413,7 @@ HKDF
 
 .. currentmodule:: cryptography.hazmat.primitives.kdf.hkdf
 
-.. class:: HKDF(algorithm, length, salt, info, backend=None)
+.. class:: HKDF(algorithm, length, salt, info)
 
     .. versionadded:: 0.2
 
@@ -488,13 +465,6 @@ HKDF
     :param bytes info: Application specific context information.  If ``None``
         is explicitly passed an empty byte string will be used.
 
-    :param backend: An optional instance of
-        :class:`~cryptography.hazmat.backends.interfaces.HMACBackend`.
-
-    :raises cryptography.exceptions.UnsupportedAlgorithm: This is raised if the
-        provided ``backend`` does not implement
-        :class:`~cryptography.hazmat.backends.interfaces.HMACBackend`
-
     :raises TypeError: This exception is raised if ``salt`` or ``info`` is not
                        ``bytes``.
 
@@ -535,7 +505,7 @@ HKDF
         raises an exception if they do not match.
 
 
-.. class:: HKDFExpand(algorithm, length, info, backend=None)
+.. class:: HKDFExpand(algorithm, length, info)
 
     .. versionadded:: 0.5
 
@@ -579,12 +549,6 @@ HKDF
     :param bytes info: Application specific context information.  If ``None``
         is explicitly passed an empty byte string will be used.
 
-    :param backend: An optional instance of
-        :class:`~cryptography.hazmat.backends.interfaces.HMACBackend`.
-
-    :raises cryptography.exceptions.UnsupportedAlgorithm: This is raised if the
-        provided ``backend`` does not implement
-        :class:`~cryptography.hazmat.backends.interfaces.HMACBackend`
     :raises TypeError: This exception is raised if ``info`` is not ``bytes``.
 
     .. method:: derive(key_material)
@@ -632,7 +596,7 @@ KBKDF
 .. currentmodule:: cryptography.hazmat.primitives.kdf.kbkdf
 
 .. class:: KBKDFHMAC(algorithm, mode, length, rlen, llen, location,\
-           label, context, fixed, backend=None)
+           label, context, fixed)
 
     .. versionadded:: 1.4
 
@@ -706,13 +670,6 @@ KBKDF
         may supply your own fixed data. If ``fixed`` is specified, ``label``
         and ``context`` is ignored.
 
-    :param backend: An optional instance of
-        :class:`~cryptography.hazmat.backends.interfaces.HMACBackend`.
-
-    :raises cryptography.exceptions.UnsupportedAlgorithm: This is raised
-        if the provided ``backend`` does not implement
-        :class:`~cryptography.hazmat.backends.interfaces.HMACBackend`
-
     :raises TypeError: This exception is raised if ``label`` or ``context``
         is not ``bytes``. Also raised if ``rlen`` or ``llen`` is not ``int``.
 
@@ -756,7 +713,7 @@ KBKDF
         raises an exception if they do not match.
 
 .. class:: KBKDFCMAC(algorithm, mode, length, rlen, llen, location,\
-           label, context, fixed, backend=None)
+           label, context, fixed)
 
     .. versionadded:: 35.0
 
@@ -831,13 +788,8 @@ KBKDF
         may supply your own fixed data. If ``fixed`` is specified, ``label``
         and ``context`` is ignored.
 
-    :param backend: An optional instance of
-        :class:`~cryptography.hazmat.backends.interfaces.CMACBackend`.
-
     :raises cryptography.exceptions.UnsupportedAlgorithm: This is raised
-        if the provided ``backend`` does not implement
-        :class:`~cryptography.hazmat.backends.interfaces.CMACBackend` or
-        ``algorithm`` is not a subclass of
+        if ``algorithm`` is not a subclass of
         :class:`~cryptography.hazmat.primitives.ciphers.CipherAlgorithm` and
         :class:`~cryptography.hazmat.primitives.ciphers.BlockCipherAlgorithm`.
 
@@ -867,12 +819,6 @@ KBKDF
                                                           :meth:`verify` is
                                                           called more than
                                                           once.
-        :raises cryptography.exceptions.UnsupportedAlgorithm: This is raised
-                if ``backend`` passed to
-                :class:`~cryptography.hazmat.primitives.kdf.kbkdf.KBKDFCMAC`
-                constructor does not support an ``algorithm`` passed to
-                :class:`~cryptography.hazmat.primitives.kdf.kbkdf.KBKDFCMAC`
-                constructor with given ``key_material``.
 
         Derives a new key from the input key material.
 
@@ -921,7 +867,7 @@ X963KDF
 
 .. currentmodule:: cryptography.hazmat.primitives.kdf.x963kdf
 
-.. class:: X963KDF(algorithm, length, otherinfo, backend=None)
+.. class:: X963KDF(algorithm, length, otherinfo)
 
     .. versionadded:: 1.1
 
@@ -967,13 +913,6 @@ X963KDF
     :param bytes sharedinfo: Application specific context information.
         If ``None`` is explicitly passed an empty byte string will be used.
 
-    :param backend: An optional instance of
-        :class:`~cryptography.hazmat.backends.interfaces.HashBackend`.
-
-    :raises cryptography.exceptions.UnsupportedAlgorithm: This is raised
-        if the provided ``backend`` does not implement
-        :class:`~cryptography.hazmat.backends.interfaces.HashBackend`
-
     :raises TypeError: This exception is raised if ``sharedinfo`` is not
         ``bytes``.
 
diff --git a/docs/hazmat/primitives/keywrap.rst b/docs/hazmat/primitives/keywrap.rst
index 9d8abbd09..323757372 100644
--- a/docs/hazmat/primitives/keywrap.rst
+++ b/docs/hazmat/primitives/keywrap.rst
@@ -11,7 +11,7 @@ to protect keys at rest or transmit them over insecure networks. Many of the
 protections offered by key wrapping are also offered by using authenticated
 :doc:`symmetric encryption </hazmat/primitives/symmetric-encryption>`.
 
-.. function:: aes_key_wrap(wrapping_key, key_to_wrap, backend=None)
+.. function:: aes_key_wrap(wrapping_key, key_to_wrap)
 
     .. versionadded:: 1.1
 
@@ -22,14 +22,9 @@ protections offered by key wrapping are also offered by using authenticated
 
     :param bytes key_to_wrap: The key to wrap.
 
-    :param backend: An optional
-        :class:`~cryptography.hazmat.backends.interfaces.CipherBackend`
-        instance that supports
-        :class:`~cryptography.hazmat.primitives.ciphers.algorithms.AES`.
-
     :return bytes: The wrapped key as bytes.
 
-.. function:: aes_key_unwrap(wrapping_key, wrapped_key, backend=None)
+.. function:: aes_key_unwrap(wrapping_key, wrapped_key)
 
     .. versionadded:: 1.1
 
@@ -40,17 +35,12 @@ protections offered by key wrapping are also offered by using authenticated
 
     :param bytes wrapped_key: The wrapped key.
 
-    :param backend: An optional
-        :class:`~cryptography.hazmat.backends.interfaces.CipherBackend`
-        instance that supports
-        :class:`~cryptography.hazmat.primitives.ciphers.algorithms.AES`.
-
     :return bytes: The unwrapped key as bytes.
 
     :raises cryptography.hazmat.primitives.keywrap.InvalidUnwrap: This is
         raised if the key is not successfully unwrapped.
 
-.. function:: aes_key_wrap_with_padding(wrapping_key, key_to_wrap, backend=None)
+.. function:: aes_key_wrap_with_padding(wrapping_key, key_to_wrap)
 
     .. versionadded:: 2.2
 
@@ -61,14 +51,9 @@ protections offered by key wrapping are also offered by using authenticated
 
     :param bytes key_to_wrap: The key to wrap.
 
-    :param backend: An optional
-        :class:`~cryptography.hazmat.backends.interfaces.CipherBackend`
-        instance that supports
-        :class:`~cryptography.hazmat.primitives.ciphers.algorithms.AES`.
-
     :return bytes: The wrapped key as bytes.
 
-.. function:: aes_key_unwrap_with_padding(wrapping_key, wrapped_key, backend=None)
+.. function:: aes_key_unwrap_with_padding(wrapping_key, wrapped_key)
 
     .. versionadded:: 2.2
 
@@ -79,11 +64,6 @@ protections offered by key wrapping are also offered by using authenticated
 
     :param bytes wrapped_key: The wrapped key.
 
-    :param backend: An optional
-        :class:`~cryptography.hazmat.backends.interfaces.CipherBackend`
-        instance that supports
-        :class:`~cryptography.hazmat.primitives.ciphers.algorithms.AES`.
-
     :return bytes: The unwrapped key as bytes.
 
     :raises cryptography.hazmat.primitives.keywrap.InvalidUnwrap: This is
diff --git a/docs/hazmat/primitives/mac/cmac.rst b/docs/hazmat/primitives/mac/cmac.rst
index b40a90a82..c7eabd9d9 100644
--- a/docs/hazmat/primitives/mac/cmac.rst
+++ b/docs/hazmat/primitives/mac/cmac.rst
@@ -17,7 +17,7 @@ of a message.
 
 A subset of CMAC with the AES-128 algorithm is described in :rfc:`4493`.
 
-.. class:: CMAC(algorithm, backend=None)
+.. class:: CMAC(algorithm)
 
     .. versionadded:: 0.4
 
@@ -33,10 +33,6 @@ A subset of CMAC with the AES-128 algorithm is described in :rfc:`4493`.
         >>> c.finalize()
         b'CT\x1d\xc8\x0e\x15\xbe4e\xdb\xb6\x84\xca\xd9Xk'
 
-    If the backend doesn't support the requested ``algorithm`` an
-    :class:`~cryptography.exceptions.UnsupportedAlgorithm` exception will be
-    raised.
-
     If ``algorithm`` isn't a
     :class:`~cryptography.hazmat.primitives.ciphers.BlockCipherAlgorithm`
     instance then ``TypeError`` will be raised.
@@ -55,13 +51,10 @@ A subset of CMAC with the AES-128 algorithm is described in :rfc:`4493`.
 
     :param algorithm: An instance of
         :class:`~cryptography.hazmat.primitives.ciphers.BlockCipherAlgorithm`.
-    :param backend: An optional instance of
-        :class:`~cryptography.hazmat.backends.interfaces.CMACBackend`.
     :raises TypeError: This is raised if the provided ``algorithm`` is not an instance of
         :class:`~cryptography.hazmat.primitives.ciphers.BlockCipherAlgorithm`
     :raises cryptography.exceptions.UnsupportedAlgorithm: This is raised if the
-        provided ``backend`` does not implement
-        :class:`~cryptography.hazmat.backends.interfaces.CMACBackend`
+        provided ``algorithm`` is unsupported.
 
     .. method:: update(data)
 
diff --git a/docs/hazmat/primitives/mac/hmac.rst b/docs/hazmat/primitives/mac/hmac.rst
index 5d44e1272..c94b7902d 100644
--- a/docs/hazmat/primitives/mac/hmac.rst
+++ b/docs/hazmat/primitives/mac/hmac.rst
@@ -15,7 +15,7 @@ message authentication codes using a cryptographic hash function coupled with a
 secret key. You can use an HMAC to verify both the integrity and authenticity
 of a message.
 
-.. class:: HMAC(key, algorithm, backend=None)
+.. class:: HMAC(key, algorithm)
 
     HMAC objects take a ``key`` and a
     :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm` instance.
@@ -35,10 +35,6 @@ of a message.
         >>> signature
         b'k\xd9\xb29\xefS\xf8\xcf\xec\xed\xbf\x95\xe6\x97X\x18\x9e%\x11DU1\x9fq}\x9a\x9c\xe0)y`='
 
-    If the backend doesn't support the requested ``algorithm`` an
-    :class:`~cryptography.exceptions.UnsupportedAlgorithm` exception will be
-    raised.
-
     If ``algorithm`` isn't a
     :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm` instance
     then ``TypeError`` will be raised.
@@ -64,13 +60,9 @@ of a message.
         :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm`
         instance such as those described in
         :ref:`Cryptographic Hashes <cryptographic-hash-algorithms>`.
-    :param backend: An optional
-        :class:`~cryptography.hazmat.backends.interfaces.HMACBackend`
-        instance.
 
     :raises cryptography.exceptions.UnsupportedAlgorithm: This is raised if the
-        provided ``backend`` does not implement
-        :class:`~cryptography.hazmat.backends.interfaces.HMACBackend`
+        provided ``algorithm`` isn't supported.
 
     .. method:: update(msg)
 
diff --git a/docs/hazmat/primitives/symmetric-encryption.rst b/docs/hazmat/primitives/symmetric-encryption.rst
index 985a9502c..dc94258fe 100644
--- a/docs/hazmat/primitives/symmetric-encryption.rst
+++ b/docs/hazmat/primitives/symmetric-encryption.rst
@@ -21,7 +21,7 @@ in an "encrypt-then-MAC" formulation as `described by Colin Percival`_.
 **To minimize the risk of security issues you should evaluate Fernet to see if
 it fits your needs before implementing anything using this module.**
 
-.. class:: Cipher(algorithm, mode, backend=None)
+.. class:: Cipher(algorithm, mode)
 
     Cipher objects combine an algorithm such as
     :class:`~cryptography.hazmat.primitives.ciphers.algorithms.AES` with a
@@ -50,13 +50,9 @@ it fits your needs before implementing anything using this module.**
     :param mode: A :class:`~cryptography.hazmat.primitives.ciphers.modes.Mode`
         instance such as those described
         :ref:`below <symmetric-encryption-modes>`.
-    :param backend: An optional
-        :class:`~cryptography.hazmat.backends.interfaces.CipherBackend`
-        instance.
 
     :raises cryptography.exceptions.UnsupportedAlgorithm: This is raised if the
-        provided ``backend`` does not implement
-        :class:`~cryptography.hazmat.backends.interfaces.CipherBackend`
+        provided ``algorithm`` is unsupported.
 
     .. method:: encryptor()
 
@@ -64,8 +60,8 @@ it fits your needs before implementing anything using this module.**
             :class:`~cryptography.hazmat.primitives.ciphers.CipherContext`
             instance.
 
-        If the backend doesn't support the requested combination of ``cipher``
-        and ``mode`` an :class:`~cryptography.exceptions.UnsupportedAlgorithm`
+        If the requested combination of ``algorithm`` and ``mode`` is
+        unsupported an :class:`~cryptography.exceptions.UnsupportedAlgorithm`
         exception will be raised.
 
     .. method:: decryptor()
@@ -74,8 +70,8 @@ it fits your needs before implementing anything using this module.**
             :class:`~cryptography.hazmat.primitives.ciphers.CipherContext`
             instance.
 
-        If the backend doesn't support the requested combination of ``cipher``
-        and ``mode`` an :class:`~cryptography.exceptions.UnsupportedAlgorithm`
+        If the requested combination of ``algorithm`` and ``mode`` is
+        unsupported an :class:`~cryptography.exceptions.UnsupportedAlgorithm`
         exception will be raised.
 
 .. _symmetric-encryption-algorithms:
@@ -741,9 +737,6 @@ Interfaces used by the symmetric cipher modes described in
         This should be the standard shorthand name for the mode, for example
         Cipher-Block Chaining mode is "CBC".
 
-        The name may be used by a backend to influence the operation of a
-        cipher in conjunction with the algorithm's name.
-
     .. method:: validate_for_algorithm(algorithm)
 
         :param cryptography.hazmat.primitives.ciphers.CipherAlgorithm algorithm:
diff --git a/docs/x509/reference.rst b/docs/x509/reference.rst
index 7d5e0575a..9944b08cd 100644
--- a/docs/x509/reference.rst
+++ b/docs/x509/reference.rst
@@ -149,7 +149,7 @@ X.509 Reference
 Loading Certificates
 ~~~~~~~~~~~~~~~~~~~~
 
-.. function:: load_pem_x509_certificate(data, backend=None)
+.. function:: load_pem_x509_certificate(data)
 
     .. versionadded:: 0.7
 
@@ -159,10 +159,6 @@ Loading Certificates
 
     :param bytes data: The PEM encoded certificate data.
 
-    :param backend: An optional backend supporting the
-        :class:`~cryptography.hazmat.backends.interfaces.X509Backend`
-        interface.
-
     :returns: An instance of :class:`~cryptography.x509.Certificate`.
 
     .. doctest::
@@ -172,7 +168,7 @@ Loading Certificates
         >>> cert.serial_number
         2
 
-.. function:: load_der_x509_certificate(data, backend=None)
+.. function:: load_der_x509_certificate(data)
 
     .. versionadded:: 0.7
 
@@ -182,16 +178,12 @@ Loading Certificates
 
     :param bytes data: The DER encoded certificate data.
 
-    :param backend: An optional backend supporting the
-        :class:`~cryptography.hazmat.backends.interfaces.X509Backend`
-        interface.
-
     :returns: An instance of :class:`~cryptography.x509.Certificate`.
 
 Loading Certificate Revocation Lists
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. function:: load_pem_x509_crl(data, backend=None)
+.. function:: load_pem_x509_crl(data)
 
     .. versionadded:: 1.1
 
@@ -201,10 +193,6 @@ Loading Certificate Revocation Lists
 
     :param bytes data: The PEM encoded request data.
 
-    :param backend: An optional backend supporting the
-        :class:`~cryptography.hazmat.backends.interfaces.X509Backend`
-        interface.
-
     :returns: An instance of
         :class:`~cryptography.x509.CertificateRevocationList`.
 
@@ -216,7 +204,7 @@ Loading Certificate Revocation Lists
         >>> isinstance(crl.signature_hash_algorithm, hashes.SHA256)
         True
 
-.. function:: load_der_x509_crl(data, backend=None)
+.. function:: load_der_x509_crl(data)
 
     .. versionadded:: 1.1
 
@@ -225,17 +213,13 @@ Loading Certificate Revocation Lists
 
     :param bytes data: The DER encoded request data.
 
-    :param backend: An optional backend supporting the
-        :class:`~cryptography.hazmat.backends.interfaces.X509Backend`
-        interface.
-
     :returns: An instance of
         :class:`~cryptography.x509.CertificateRevocationList`.
 
 Loading Certificate Signing Requests
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. function:: load_pem_x509_csr(data, backend=None)
+.. function:: load_pem_x509_csr(data)
 
     .. versionadded:: 0.9
 
@@ -246,10 +230,6 @@ Loading Certificate Signing Requests
 
     :param bytes data: The PEM encoded request data.
 
-    :param backend: An optional backend supporting the
-        :class:`~cryptography.hazmat.backends.interfaces.X509Backend`
-        interface.
-
     :returns: An instance of
         :class:`~cryptography.x509.CertificateSigningRequest`.
 
@@ -261,7 +241,7 @@ Loading Certificate Signing Requests
         >>> isinstance(csr.signature_hash_algorithm, hashes.SHA256)
         True
 
-.. function:: load_der_x509_csr(data, backend=None)
+.. function:: load_der_x509_csr(data)
 
     .. versionadded:: 0.9
 
@@ -270,10 +250,6 @@ Loading Certificate Signing Requests
 
     :param bytes data: The DER encoded request data.
 
-    :param backend: An optional backend supporting the
-        :class:`~cryptography.hazmat.backends.interfaces.X509Backend`
-        interface.
-
     :returns: An instance of
         :class:`~cryptography.x509.CertificateSigningRequest`.
 
@@ -774,7 +750,7 @@ X.509 Certificate Builder
         :param critical: Set to ``True`` if the extension must be understood and
              handled by whoever reads the certificate.
 
-    .. method:: sign(private_key, algorithm, backend=None)
+    .. method:: sign(private_key, algorithm)
 
         Sign the certificate using the CA's private key.
 
@@ -797,11 +773,6 @@ X.509 Certificate Builder
             :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm`
             otherwise.
 
-        :param backend: An optional backend used to build the certificate.
-            Must support the
-            :class:`~cryptography.hazmat.backends.interfaces.X509Backend`
-            interface.
-
         :returns: :class:`~cryptography.x509.Certificate`
 
 
@@ -1012,7 +983,7 @@ X.509 Certificate Revocation List Builder
             obtained from an existing CRL or created with
             :class:`~cryptography.x509.RevokedCertificateBuilder`.
 
-    .. method:: sign(private_key, algorithm, backend=None)
+    .. method:: sign(private_key, algorithm)
 
         Sign this CRL using the CA's private key.
 
@@ -1035,11 +1006,6 @@ X.509 Certificate Revocation List Builder
             :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm`
             otherwise.
 
-        :param backend: An optional backend used to build the CRL.
-            Must support the
-            :class:`~cryptography.hazmat.backends.interfaces.X509Backend`
-            interface.
-
         :returns: :class:`~cryptography.x509.CertificateRevocationList`
 
 X.509 Revoked Certificate Object
@@ -1130,14 +1096,9 @@ X.509 Revoked Certificate Builder
         :param critical: Set to ``True`` if the extension must be understood and
              handled.
 
-    .. method:: build(backend=None)
-
-        Create a revoked certificate object using the provided backend.
+    .. method:: build()
 
-        :param backend: An optional backend used to build the revoked
-            certificate.  Must support the
-            :class:`~cryptography.hazmat.backends.interfaces.X509Backend`
-            interface.
+        Create a revoked certificate object.
 
         :returns: :class:`~cryptography.x509.RevokedCertificate`
 
@@ -1200,12 +1161,7 @@ X.509 CSR (Certificate Signing Request) Builder Object
         :returns: A new
             :class:`~cryptography.x509.CertificateSigningRequestBuilder`.
 
-    .. method:: sign(private_key, algorithm, backend=None)
-
-        :param backend: An optional backend used to sign the request.
-            Must support the
-            :class:`~cryptography.hazmat.backends.interfaces.X509Backend`
-            interface.
+    .. method:: sign(private_key, algorithm)
 
         :param private_key: The
             :class:`~cryptography.hazmat.primitives.asymmetric.rsa.RSAPrivateKey`,
@@ -1282,14 +1238,10 @@ X.509 CSR (Certificate Signing Request) Builder Object
             >>> cert.subject.get_attributes_for_oid(NameOID.COMMON_NAME)
             [<NameAttribute(oid=<ObjectIdentifier(oid=2.5.4.3, name=commonName)>, value='Good CA')>]
 
-    .. method:: public_bytes(backend=None)
+    .. method:: public_bytes()
 
         .. versionadded:: 1.6
 
-        :param backend: An optional backend supporting the
-            :class:`~cryptography.hazmat.backends.interfaces.X509Backend`
-            interface.
-
         :return bytes: The DER encoded name.
 
     .. method:: rfc4514_string(attr_name_overrides=None)