[B<-in filename>]
[B<-out filename>]
[B<-key keyfile>]
-[B<-passin password>]
-[B<-envpassin var>]
+[B<-passin arg>]
[B<-challenge string>]
[B<-pubkey>]
[B<-spkac spkacname>]
[B<-spksect section>]
[B<-noout>]
[B<-verify>]
-
+[B<-engine id>]
=head1 DESCRIPTION
=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.
+the input file password source. For more information about the format of B<arg>
+see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
=item B<-challenge string>
verifies the digital signature on the supplied SPKAC.
+=item B<-engine id>
+
+specifying an engine (by its unique B<id> string) will cause B<spkac>
+to attempt to obtain a functional reference to the specified engine,
+thus initialising it if needed. The engine will then be set as the default
+for all available algorithms.
=back
=head1 SEE ALSO
-L<ca(1)|ca(1)>
+L<ca(1)>
=cut