Merge branch 'master' into urandom-engine

* master:
  PKCS #1 RSA test vector loader
  Removed pointless anchor
  Docs need virtualenv as well
  Everything about bash is the worst
  Some reST markup nonsense
  Fix for OS X
  More clearly describe the behavior of constant_time.bytes_eq
  Run the doc tests under OS X
  Made OpenSSL's derive_pbkdf2_hmac raise the right exception
  Document which backends implement which itnerfaces. Fixes #538
  pep8
  Fixed a typo in the docs
  Make the default backend be a multi-backend

Conflicts:
	tests/hazmat/backends/test_openssl.py

4 files changed, 31 insertions, 9 deletions

diff --git a/docs/hazmat/backends/interfaces.rst b/docs/hazmat/backends/interfaces.rst
index 49e4c88c..5131ca12 100644
--- a/docs/hazmat/backends/interfaces.rst
+++ b/docs/hazmat/backends/interfaces.rst
@@ -19,6 +19,11 @@ A specific ``backend`` may provide one or more of these interfaces.
     A backend which provides methods for using ciphers for encryption
     and decryption.
 
+    The following backends implement this interface:
+
+    * :doc:`/hazmat/backends/openssl`
+    * :doc:`/hazmat/backends/commoncrypto`
+
     .. method:: cipher_supported(cipher, mode)
 
         Check if a ``cipher`` and ``mode`` combination is supported by
@@ -76,6 +81,11 @@ A specific ``backend`` may provide one or more of these interfaces.
 
     A backend with methods for using cryptographic hash functions.
 
+    The following backends implement this interface:
+
+    * :doc:`/hazmat/backends/openssl`
+    * :doc:`/hazmat/backends/commoncrypto`
+
     .. method:: hash_supported(algorithm)
 
         Check if the specified ``algorithm`` is supported by this backend.
@@ -107,6 +117,11 @@ A specific ``backend`` may provide one or more of these interfaces.
     A backend with methods for using cryptographic hash functions as message
     authentication codes.
 
+    The following backends implement this interface:
+
+    * :doc:`/hazmat/backends/openssl`
+    * :doc:`/hazmat/backends/commoncrypto`
+
     .. method:: hmac_supported(algorithm)
 
         Check if the specified ``algorithm`` is supported by this backend.
@@ -139,6 +154,11 @@ A specific ``backend`` may provide one or more of these interfaces.
 
     A backend with methods for using PBKDF2 using HMAC as a PRF.
 
+    The following backends implement this interface:
+
+    * :doc:`/hazmat/backends/openssl`
+    * :doc:`/hazmat/backends/commoncrypto`
+
     .. method:: pbkdf2_hmac_supported(algorithm)
 
         Check if the specified ``algorithm`` is supported by this backend.
@@ -171,4 +191,3 @@ A specific ``backend`` may provide one or more of these interfaces.
             the derived key. This is typically a password.
 
         :return bytes: Derived key.
-
diff --git a/docs/hazmat/backends/multibackend.rst b/docs/hazmat/backends/multibackend.rst
index 63177bef..95538ac8 100644
--- a/docs/hazmat/backends/multibackend.rst
+++ b/docs/hazmat/backends/multibackend.rst
@@ -18,10 +18,10 @@ MultiBackend
         >>> from cryptography.hazmat.primitives import hashes
         >>> backend1.hash_supported(hashes.SHA256())
         False
-        >>> backend2.hash_supported(hashes.SHA1())
+        >>> backend2.hash_supported(hashes.SHA256())
         True
         >>> multi_backend = MultiBackend([backend1, backend2])
-        >>> multi_backend.hash_supported(hashes.SHA1())
+        >>> multi_backend.hash_supported(hashes.SHA256())
         True
 
     :param backends: A ``list`` of backend objects. Backends are checked for
diff --git a/docs/hazmat/bindings/commoncrypto.rst b/docs/hazmat/bindings/commoncrypto.rst
index c4f614c2..50dbe69a 100644
--- a/docs/hazmat/bindings/commoncrypto.rst
+++ b/docs/hazmat/bindings/commoncrypto.rst
@@ -27,4 +27,4 @@ Mac OS X.
 
 
 .. _`CFFI`: https://cffi.readthedocs.org/
-.. _`CommonCrypto`: https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man3/Common%20Crypto.3cc.html#//apple_ref/doc/man/3cc/CommonCrypto
+.. _`CommonCrypto`: https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man3/Common%20Crypto.3cc.html
diff --git a/docs/hazmat/primitives/constant-time.rst b/docs/hazmat/primitives/constant-time.rst
index 632e7c68..c6fcb3a3 100644
--- a/docs/hazmat/primitives/constant-time.rst
+++ b/docs/hazmat/primitives/constant-time.rst
@@ -19,8 +19,10 @@ about the timing attacks on KeyCzar and Java's ``MessageDigest.isEqual()``.
 
 .. function:: bytes_eq(a, b)
 
-    Compare ``a`` and ``b`` to one another in constant time if they are of the
-    same length.
+    Compares ``a`` and ``b`` with one another. If ``a`` and ``b`` have
+    different lengths, this returns ``False`` immediately. Otherwise it
+    compares them in a way that takes the same amount of time, regardless of
+    how many characters are the same between the two.
 
     .. doctest::
 
@@ -30,9 +32,10 @@ about the timing attacks on KeyCzar and Java's ``MessageDigest.isEqual()``.
         >>> constant_time.bytes_eq(b"foo", b"bar")
         False
 
-    :param a bytes: The left-hand side.
-    :param b bytes: The right-hand side.
-    :returns boolean: True if ``a`` has the same bytes as ``b``.
+    :param bytes a: The left-hand side.
+    :param bytes b: The right-hand side.
+    :returns bool: ``True`` if ``a`` has the same bytes as ``b``, otherwise
+                   ``False``.
 
 
 .. _`Coda Hale's blog post`: http://codahale.com/a-lesson-in-timing-attacks/