[B<-check>]
[B<-pubin>]
[B<-pubout>]
+[B<-engine id>]
=head1 DESCRIPTION
key will be output instead. This option is automatically set if
the input is a public key.
+=item B<-engine id>
+
+specifying an engine (by its unique B<id> string) will cause B<rsa>
+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 NOTES