diff --git a/testsite/tls/templates/wsgi.example.com_https.cfg b/testsite/tls/templates/wsgi.example.com_https.cfg
index e15e9e21e4723527b912b46cb712e6069cd9883c..442aa3e400ff278f2205d90b493d8d518b7b8b9b 100644
--- a/testsite/tls/templates/wsgi.example.com_https.cfg
+++ b/testsite/tls/templates/wsgi.example.com_https.cfg
@@ -25,3 +25,8 @@ tls_www_server
 # Whether this certificate will be used to sign data (needed
 # in TLS DHE ciphersuites).
 signing_key
+
+# Whether this certificate will be used to encrypt data (needed
+# in TLS RSA ciphersuites). Note that it is preferred to use different
+# keys for encryption and signing.
+encryption_key