Merge remote-tracking branch 'origin/master' into pyopenssl-test_crypto-with-optionals

6 files changed, 77 insertions, 15 deletions

diff --git a/docs/api-stability.rst b/docs/api-stability.rst
new file mode 100644
index 00000000..e87cc140
--- /dev/null
+++ b/docs/api-stability.rst
@@ -0,0 +1,51 @@
+API Stability
+=============
+
+From its first release, ``cryptography`` will have a strong API stability
+policy.
+
+What does this policy cover?
+----------------------------
+
+This policy includes any API or behavior which is documented in this
+documentation.
+
+What does "stable" mean?
+------------------------
+
+* Public APIs will not be removed or renamed without providing a compatibility
+  alias.
+* The behavior of existing APIs will not change.
+
+What doesn't this policy cover?
+-------------------------------
+
+* We may add new features, things like the result of ``dir(obj))`` or the
+  contents of ``obj.__dict__`` may change.
+* Objects are not guaranteed to be pickleable, and pickled objects from one
+  version of ``cryptography`` may not be loadable in future versions.
+* Development versions of ``cryptography``. Before a feature is in a release,
+  it is not covered by this policy and may change.
+
+Security
+~~~~~~~~
+
+One exception to our API stability policy is for security. We will violate this
+policy as necessary in order to resolve a security issue or harden
+``cryptography`` against a possible attack.
+
+Deprecation
+-----------
+
+From time to time we will want to change the behavior of an API or remove it
+entirely. In that case, here's how the process will work:
+
+* In ``cryptography X.Y`` the feature exists.
+* In ``cryptography X.Y+1`` using that feature will emit a
+  ``PendingDeprecationWarning``.
+* In ``cryptography X.Y+2`` using that feature will emit a
+  ``DeprecationWarning``.
+* In ``cryptography X.Y+3`` the feature will be removed or changed.
+
+In short, code which runs without warnings will always continue to work for a
+period of two releases.
diff --git a/docs/contributing.rst b/docs/contributing.rst
index 744f2098..620e1b6a 100644
--- a/docs/contributing.rst
+++ b/docs/contributing.rst
@@ -136,7 +136,6 @@ Include a space after commas between parameters:
     // Bad
     long f(int,char *)
 
-
 Documentation
 -------------
 
diff --git a/docs/hazmat/backends/index.rst b/docs/hazmat/backends/index.rst
index a89cf0d5..06951281 100644
--- a/docs/hazmat/backends/index.rst
+++ b/docs/hazmat/backends/index.rst
@@ -1,17 +1,10 @@
 .. hazmat::
 
-Bindings
+Backends
 ========
 
-.. toctree::
-    :maxdepth: 1
-
-    openssl
-    interfaces
-
-
-Getting a Backend Provider
-~~~~~~~~~~~~~~~~~~~~~~~~~~
+Getting a Backend
+-----------------
 
 .. currentmodule:: cryptography.hazmat.backends
 
@@ -19,8 +12,7 @@ Getting a Backend Provider
 the widest number of supported cryptographic algorithms as well as supporting
 platform specific implementations.
 
-You can get the default backend by calling
-:func:`~default_backend`.
+You can get the default backend by calling :func:`~default_backend`.
 
 The default backend will change over time as we implement new backends and
 the libraries we use in those backends changes.
@@ -32,3 +24,11 @@ the libraries we use in those backends changes.
         :class:`~interfaces.CipherBackend`, :class:`~interfaces.HashBackend`, and
         :class:`~interfaces.HMACBackend`.
 
+Individual Backends
+-------------------
+
+.. toctree::
+    :maxdepth: 1
+
+    openssl
+    interfaces
diff --git a/docs/hazmat/backends/interfaces.rst b/docs/hazmat/backends/interfaces.rst
index b524943d..5b6cd64d 100644
--- a/docs/hazmat/backends/interfaces.rst
+++ b/docs/hazmat/backends/interfaces.rst
@@ -126,6 +126,17 @@ A specific ``backend`` may provide one or more of these interfaces.
     A backend with methods for using cryptographic hash functions as message
     authentication codes.
 
+    .. method:: hmac_supported(algorithm)
+
+        Check if the specified ``algorithm`` is supported by this backend.
+
+        :param algorithm: An instance of a
+            :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm`
+            provider.
+
+        :returns: ``True`` if the specified ``algorithm`` is supported for HMAC
+            by this backend, otherwise ``False``.
+
     .. method:: create_hmac_ctx(algorithm)
 
         Create a
diff --git a/docs/hazmat/backends/openssl.rst b/docs/hazmat/backends/openssl.rst
index 12fbff04..5e51c75e 100644
--- a/docs/hazmat/backends/openssl.rst
+++ b/docs/hazmat/backends/openssl.rst
@@ -1,7 +1,7 @@
 .. hazmat::
 
-OpenSSL
-=======
+OpenSSL Backend
+===============
 
 These are `CFFI`_ bindings to the `OpenSSL`_ C library.
 
diff --git a/docs/index.rst b/docs/index.rst
index 381063df..70558bda 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -75,4 +75,5 @@ The ``cryptography`` open source project
 
     contributing
     security
+    api-stability
     community