Merge branch 'master' into pbkdf2-commoncrypto

* master:
  a bit more language work + changelog changes for pbkdf2hmac
  one more style fix
  a few typo fixes, capitalization, etc
  switch to private attributes in pbkdf2hmac
  expand docs to talk more about the purposes of KDFs
  update docs re: PBKDF2HMAC iterations
  add test for null char replacement
  Added installation section to index.rst
  called -> used
  quotes inside, diff examples
  Expose this method because probably someone will need it eventually
  fix spacing, remove versionadded since HashAlgorithm was in 0.1
  document HashAlgorithm
  Added canonical installation document with details about various platforms, fixes #519
  update docs for pbkdf2
  Add bindings for X509_REQ_get_extensions.
  add Konstantinos Koukopoulos to AUTHORS.rst
  review fixes
  doc updates based on review

Conflicts:
	docs/changelog.rst

2 files changed, 8 insertions, 55 deletions

diff --git a/docs/hazmat/backends/interfaces.rst b/docs/hazmat/backends/interfaces.rst
index e22c6bb3..49e4c88c 100644
--- a/docs/hazmat/backends/interfaces.rst
+++ b/docs/hazmat/backends/interfaces.rst
@@ -37,7 +37,7 @@ A specific ``backend`` may provide one or more of these interfaces.
     .. method:: create_symmetric_encryption_ctx(cipher, mode)
 
         Create a
-        :class:`~cryptogrpahy.hazmat.primitives.interfaces.CipherContext` that
+        :class:`~cryptography.hazmat.primitives.interfaces.CipherContext` that
         can be used for encrypting data with the symmetric ``cipher`` using
         the given ``mode``.
 
@@ -56,7 +56,7 @@ A specific ``backend`` may provide one or more of these interfaces.
     .. method:: create_symmetric_decryption_ctx(cipher, mode)
 
         Create a
-        :class:`~cryptogrpahy.hazmat.primitives.interfaces.CipherContext` that
+        :class:`~cryptography.hazmat.primitives.interfaces.CipherContext` that
         can be used for decrypting data with the symmetric ``cipher`` using
         the given ``mode``.
 
@@ -91,7 +91,7 @@ A specific ``backend`` may provide one or more of these interfaces.
     .. method:: create_hash_ctx(algorithm)
 
         Create a
-        :class:`~cryptogrpahy.hazmat.primitives.interfaces.HashContext` that
+        :class:`~cryptography.hazmat.primitives.interfaces.HashContext` that
         uses the specified ``algorithm`` to calculate a message digest.
 
         :param algorithm: An instance of a
@@ -121,7 +121,7 @@ A specific ``backend`` may provide one or more of these interfaces.
     .. method:: create_hmac_ctx(algorithm)
 
         Create a
-        :class:`~cryptogrpahy.hazmat.primitives.interfaces.HashContext` that
+        :class:`~cryptography.hazmat.primitives.interfaces.HashContext` that
         uses the specified ``algorithm`` to calculate a hash-based message
         authentication code.
 
@@ -133,7 +133,6 @@ A specific ``backend`` may provide one or more of these interfaces.
             :class:`~cryptography.hazmat.primitives.interfaces.HashContext`
 
 
-
 .. class:: PBKDF2HMACBackend
 
     .. versionadded:: 0.2
@@ -144,7 +143,7 @@ A specific ``backend`` may provide one or more of these interfaces.
 
         Check if the specified ``algorithm`` is supported by this backend.
 
-        :param prf: An instance of a
+        :param algorithm: An instance of a
             :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
             provider.
 
@@ -164,7 +163,9 @@ A specific ``backend`` may provide one or more of these interfaces.
         :param bytes salt: A salt.
 
         :param int iterations: The number of iterations to perform of the hash
-            function.
+            function. This can be used to control the length of time the
+            operation takes. Higher numbers help mitigate brute force attacks
+            against derived keys.
 
         :param bytes key_material: The key material to use as a basis for
             the derived key. This is typically a password.
diff --git a/docs/hazmat/backends/openssl.rst b/docs/hazmat/backends/openssl.rst
index 926ec7d1..12d2d9f6 100644
--- a/docs/hazmat/backends/openssl.rst
+++ b/docs/hazmat/backends/openssl.rst
@@ -13,52 +13,4 @@ The `OpenSSL`_ C library.
 
         The string name of this backend: ``"openssl"``
 
-Using your own OpenSSL on Linux
--------------------------------
-
-Python links to OpenSSL for its own purposes and this can sometimes cause
-problems when you wish to use a different version of OpenSSL with cryptography.
-If you want to use cryptography with your own build of OpenSSL you will need to
-make sure that the build is configured correctly so that your version of
-OpenSSL doesn't conflict with Python's.
-
-The options you need to add allow the linker to identify every symbol correctly
-even when multiple versions of the library are linked into the same program. If
-you are using your distribution's source packages these will probably be
-patched in for you already, otherwise you'll need to use options something like
-this when configuring OpenSSL:
-
-.. code-block:: console
-
-    $ ./config -Wl,--version-script=openssl.ld -Wl,-Bsymbolic-functions -fPIC shared
-
-You'll also need to generate your own ``openssl.ld`` file. For example::
-
-    OPENSSL_1.0.1F_CUSTOM {
-        global:
-            *;
-    };
-
-You should replace the version string on the first line as appropriate for your
-build.
-
-Using your own OpenSSL on OS X
-------------------------------
-
-To link cryptography against a custom version of OpenSSL you'll need to set
-``ARCHFLAGS``, ``LDFLAGS``, and ``CFLAGS``. OpenSSL can be installed via
-`Homebrew`_:
-
-.. code-block:: console
-
-    $ brew install openssl
-
-Then install cryptography linking against the brewed version:
-
-.. code-block:: console
-
-    $ env ARCHFLAGS="-arch x86_64" LDFLAGS="-L/usr/local/opt/openssl/lib" CFLAGS="-I/usr/local/opt/openssl/include" pip install cryptography
-
-
 .. _`OpenSSL`: https://www.openssl.org/
-.. _`Homebrew`: http://brew.sh