Fix #12 Allow pickling of keys.
Pickling is now possible, with the added note that one should never
unpickle from an untrusted or unauthenticated source.
diff --git a/doc/reference.rst b/doc/reference.rst
index d80416a..ce9c1b9 100644
--- a/doc/reference.rst
+++ b/doc/reference.rst
@@ -21,6 +21,14 @@
Classes
--------------------------------------------------
+.. note::
+
+ Storing public and private keys via the `pickle` module is possible.
+ However, it is insecure to load a key from an untrusted source.
+ The pickle module is not secure against erroneous or maliciously
+ constructed data. Never unpickle data received from an untrusted
+ or unauthenticated source.
+
.. autoclass:: rsa.PublicKey
:members:
:inherited-members: