Merge branch 'master' into urandom-engine

* master: (66 commits)
  Chanloge + versionadded
  Added an example usage
  Typo fix
  Added to toctree
  Rename and document
  Linkify the things we have that others don't
  add HKDF to changelog
  Strings have quote marks at both ends.
  HKDF example.
  Properly mark all test cases as dependant on HMAC.
  Remove language about the separate stages of HKDF until we expose multiple stages of HKDF.
  Don't forget InvalidKey.
  Fix typo
  Import exception classes instead of the exceptions module.
  Lose the bit about passwords.
  https a bunch of links.
  Pseudorandom is a word.
  Backtick the entire equation.
  Clarify salt language and link to the paper in addition to the RFC.
  Don't expose extract and expand on this class yet because we don't know how best to expose verify functionality, continue testing the stages using the private methods.
  ...

Conflicts:
	docs/hazmat/backends/openssl.rst

4 files changed, 48 insertions, 1 deletions

diff --git a/docs/hazmat/backends/commoncrypto.rst b/docs/hazmat/backends/commoncrypto.rst
index af2032b6..16a61337 100644
--- a/docs/hazmat/backends/commoncrypto.rst
+++ b/docs/hazmat/backends/commoncrypto.rst
@@ -11,7 +11,16 @@ The `CommonCrypto`_ C library provided by Apple on OS X and iOS.
 
 .. data:: cryptography.hazmat.backends.commoncrypto.backend
 
-    This is the exposed API for the CommonCrypto backend. It has one public attribute.
+    This is the exposed API for the CommonCrypto backend.
+
+    It implements the following interfaces:
+
+    * :class:`~cryptography.hazmat.backends.interfaces.CipherBackend`
+    * :class:`~cryptography.hazmat.backends.interfaces.HashBackend`
+    * :class:`~cryptography.hazmat.backends.interfaces.HMACBackend`
+    * :class:`~cryptography.hazmat.backends.interfaces.PBKDF2HMACBackend`
+
+    It has one additional public attribute.
 
     .. attribute:: name
 
diff --git a/docs/hazmat/backends/index.rst b/docs/hazmat/backends/index.rst
index dbc0724e..983a44e9 100644
--- a/docs/hazmat/backends/index.rst
+++ b/docs/hazmat/backends/index.rst
@@ -32,4 +32,5 @@ Individual Backends
 
     openssl
     commoncrypto
+    multibackend
     interfaces
diff --git a/docs/hazmat/backends/multibackend.rst b/docs/hazmat/backends/multibackend.rst
new file mode 100644
index 00000000..63177bef
--- /dev/null
+++ b/docs/hazmat/backends/multibackend.rst
@@ -0,0 +1,28 @@
+.. hazmat::
+
+MultiBackend
+============
+
+.. currentmodule:: cryptography.hazmat.backends.multibackend
+
+.. class:: MultiBackend(backends)
+
+    .. versionadded:: 0.2
+
+    This class allows you to combine multiple backends into a single backend
+    which offers the combined features of all of its constituents.
+
+    .. code-block:: pycon
+
+        >>> from cryptography.hazmat.backends.multibackend import MultiBackend
+        >>> from cryptography.hazmat.primitives import hashes
+        >>> backend1.hash_supported(hashes.SHA256())
+        False
+        >>> backend2.hash_supported(hashes.SHA1())
+        True
+        >>> multi_backend = MultiBackend([backend1, backend2])
+        >>> multi_backend.hash_supported(hashes.SHA1())
+        True
+
+    :param backends: A ``list`` of backend objects. Backends are checked for
+                     feature support in the order they appear in this list.
diff --git a/docs/hazmat/backends/openssl.rst b/docs/hazmat/backends/openssl.rst
index 1d40b93c..f7d6b710 100644
--- a/docs/hazmat/backends/openssl.rst
+++ b/docs/hazmat/backends/openssl.rst
@@ -9,6 +9,15 @@ The `OpenSSL`_ C library.
 
     This is the exposed API for the OpenSSL backend.
 
+    It implements the following interfaces:
+
+    * :class:`~cryptography.hazmat.backends.interfaces.CipherBackend`
+    * :class:`~cryptography.hazmat.backends.interfaces.HashBackend`
+    * :class:`~cryptography.hazmat.backends.interfaces.HMACBackend`
+    * :class:`~cryptography.hazmat.backends.interfaces.PBKDF2HMACBackend`
+
+    It also exposes the following:
+
     .. attribute:: name
 
         The string name of this backend: ``"openssl"``