diff --git a/docs/manpages/ndnsec-key-gen.rst b/docs/manpages/ndnsec-key-gen.rst
index fe70233..21bf3c4 100644
--- a/docs/manpages/ndnsec-key-gen.rst
+++ b/docs/manpages/ndnsec-key-gen.rst
@@ -8,7 +8,7 @@
 
 ::
 
-    $ ndnsec-key-gen [-h] [-n] identity
+    $ ndnsec-key-gen [-h] [-n] [-d] identity
 
 Description
 -----------
@@ -25,6 +25,9 @@
 ``-n``
   Do not set the identity as the system default identity.
 
+``-d``
+  Generate Data-Signing-Key (DSK) instead of the default Key-Signing-Key (KSK).
+
 Examples
 --------