Add command line password options to the reamining utilities,
amend docs.

doc/apps/spkac.pod

diff --git a/doc/apps/spkac.pod b/doc/apps/spkac.pod
index c58768e..846b9a9 100644
--- a/doc/apps/spkac.pod
+++ b/doc/apps/spkac.pod
@@ -10,6 +10,8 @@
 [B<-in filename>]
 [B<-out filename>]
 [B<-key keyfile>]
+[B<-passin password>]
+[B<-envpassin var>]
 [B<-challenge string>]
 [B<-pubkey>]
 [B<-spkac spkacname>]
@@ -44,6 +46,17 @@
 B<-in>, B<-noout>, B<-spksect> and B<-verify> options are ignored if
 present.
 
+=item B<-passin password>
+
+the private key file password. Since certain utilities like "ps" make the
+command line visible this option should be used with caution. Ignored if
+the B<-key> argument is not used.
+
+=item B<-envpassin var>
+
+read the private key file password from the environment variable B<var>.
+Ignored if the B<-key> argument is not used.
+
 =item B<-challenge string>
 
 specifies the challenge string if an SPKAC is being created.