Use https:// URLs when referring to python.org hosts.
diff --git a/Doc/howto/descriptor.rst b/Doc/howto/descriptor.rst
index d644512..abedfaa 100644
--- a/Doc/howto/descriptor.rst
+++ b/Doc/howto/descriptor.rst
@@ -133,7 +133,7 @@
 invoked unless an old-style class is involved.  The implementation details are
 in :c:func:`super_getattro()` in :source:`Objects/typeobject.c`.
 
-.. _`Guido's Tutorial`: http://www.python.org/2.2.3/descrintro.html#cooperation
+.. _`Guido's Tutorial`: https://www.python.org/2.2.3/descrintro.html#cooperation
 
 The details above show that the mechanism for descriptors is embedded in the
 :meth:`__getattribute__()` methods for :class:`object`, :class:`type`, and