doc/accounts.md

@@ -261,8 +261,15 @@ Alternatively, or additionally, you can have per-host sudo passwords
 -- just select the appropriate host in the pull-down box.
 
 Once set on the web interface, you will have to confirm the new
-settings by sending a signed challenge to the mail interface.  Please
-ensure you don't introduce any additional line breaks.
+settings by sending a signed challenge to the mail interface. The
+challenge is a single line, without line breaks, provided by the web
+interface. With the challenge first you will need to produce an
+openpgp signature:
+
+    echo 'confirm sudopassword ...' | gpg --armor --sign
+
+With it you can compose an email to changes@db.torproject.org, sending
+the challenge in the body followed by the openpgp signature.
 
 Note that setting a sudo password will only enable you to use sudo to
 configured accounts on configured hosts. Consult the output of "sudo