Crypt the swapfile.
diff --git a/runtime/doc/editing.txt b/runtime/doc/editing.txt
index a10e822..a89d8bb 100644
--- a/runtime/doc/editing.txt
+++ b/runtime/doc/editing.txt
@@ -1332,10 +1332,12 @@
Vim is able to write files encrypted, and read them back. The encrypted text
cannot be read without the right key.
-Note: The swapfile and text in memory is not encrypted. A system
-administrator will be able to see your text while you are editing it.
-When filtering text with ":!filter" or using ":w !command" the text is not
-encrypted, this may reveal it to others.
+The text in the swap file and the undo file is also encrypted.
+
+Note: The text in memory is not encrypted. A system administrator may be able
+to see your text while you are editing it. When filtering text with
+":!filter" or using ":w !command" the text is not encrypted, this may reveal
+it to others. The 'viminfo' file is not encrypted.
WARNING: If you make a typo when entering the key and then write the file and
exit, the text will be lost!