diff --git a/docs/manpages/ndnsec-import.rst b/docs/manpages/ndnsec-import.rst
index fbc8bc9..c81964a 100644
--- a/docs/manpages/ndnsec-import.rst
+++ b/docs/manpages/ndnsec-import.rst
@@ -20,6 +20,12 @@
 ``-h``
   Print a help message.
 
+``-P passphrase``
+  Passphrase to use for the export. If not specified (or specified an empty passphrase), the
+  user is interactively asked to input the passphrase on the terminal. Note that specifying
+  passphrase via -P is insecure, as it can potentially end up in shell history, be visible in
+  ps output, etc.
+
 ``input``
   Read from an input file. Specify ``-`` to read from the standard input.