[B<-in file>]
[B<-out file>]
[B<-inkey file>]
+[B<-keyform PEM|DER|ENGINE>]
[B<-pubin>]
[B<-certin>]
[B<-sign>]
the input key file, by default it should be an RSA private key.
+=item B<-keyform PEM|DER|ENGINE>
+
+the key format PEM, DER or ENGINE.
+
=item B<-pubin>
the input file is an RSA public key.