Document new hash_algorithms config key
diff --git a/src/config/auth.rst b/src/config/auth.rst
index a1f393f..cb92f31 100644
--- a/src/config/auth.rst
+++ b/src/config/auth.rst
@@ -196,6 +196,33 @@
[chttpd_auth]
authentication_redirect = /_utils/session.html
+ .. config:option:: hash_algorithms :: Supported hash algorithms for cookie auth
+
+ .. versionadded:: 3.3
+
+ Sets the HMAC hash algorithm used for cookie authentication. You can provide a
+ comma-separated list of hash algorithms. New cookie sessions or
+ session updates are calculated with the first hash algorithm. All values in the
+ list can be used to decode the cookie session. ::
+
+ [chttpd_auth]
+ hash_algorithms = sha256, sha
+
+ .. note::
+ You can select any hash algorithm the version of erlang used in your CouchDB
+ install supports. The common list of available hashes might be: ::
+
+ sha, sha224, sha256, sha384, sha512
+
+ To retrieve a complete list of supported hash algorithms you can use our
+ ``bin/remsh`` script and retrieve a full list of available hash algorithms
+ with ``crypto:supports(hashs).``.
+
+ .. warning::
+ We do not recommend using the following hash algorithms: ::
+
+ md4, md5
+
.. config:option:: iterations :: PBKDF2 iterations count
.. versionadded:: 1.3
