update hmac docs
diff --git a/docs/hazmat/primitives/hmac.rst b/docs/hazmat/primitives/hmac.rst
index aec406b..bfbe325 100644
--- a/docs/hazmat/primitives/hmac.rst
+++ b/docs/hazmat/primitives/hmac.rst
@@ -21,9 +21,10 @@
.. class:: cryptography.hazmat.primitives.hmac.HMAC(key, msg=None, digestmod=None)
HMAC objects take a ``key``, a hash class derived from
- :class:`~cryptography.primitives.hashes.BaseHash`, and optional msg. The
- ``key`` should be randomly generated bytes and the length of the
- ``block_size`` of the hash. You must keep the ``key`` secret.
+ :class:`~cryptography.primitives.hashes.BaseHash`, and optional message.
+ The ``key`` should be randomly generated bytes and is recommended to be
+ equal in length to the ``digest_size`` of the hash function chosen.
+ You must keep the ``key`` secret.
.. doctest::
@@ -35,7 +36,7 @@
.. method:: update(msg)
- :param bytes msg: The bytes you wish to hash.
+ :param bytes msg: The bytes to hash and authenticate.
.. method:: copy()