openssl/doc/apps/dsaparam.pod

=pod

=head1 NAME

dsaparam - DSA parameter manipulation and generation

=head1 SYNOPSIS

B<openssl dsaparam>
[B<-inform DER|PEM>]
[B<-outform DER|PEM>]
[B<-in filename>]
[B<-out filename>]
[B<-noout>]
[B<-text>]
[B<-C>]
[B<-rand file(s)>]
[B<-genkey>]
[B<-engine id>]
[B<numbits>]

=head1 DESCRIPTION

This command is used to manipulate or generate DSA parameter files.

=head1 OPTIONS

=over 4

=item B<-inform DER|PEM>

This specifies the input format. The B<DER> option uses an ASN1 DER encoded
form compatible with RFC2459 (PKIX) DSS-Parms that is a SEQUENCE consisting
of p, q and g respectively. The PEM form is the default format: it consists
of the B<DER> format base64 encoded with additional header and footer lines.

=item B<-outform DER|PEM>

This specifies the output format, the options have the same meaning as the 
B<-inform> option.

=item B<-in filename>

This specifies the input filename to read parameters from or standard input if
this option is not specified. If the B<numbits> parameter is included then
this option will be ignored.

=item B<-out filename>

This specifies the output filename parameters to. Standard output is used
if this option is not present. The output filename should B<not> be the same
as the input filename.

=item B<-noout>

this option inhibits the output of the encoded version of the parameters.

=item B<-text>

this option prints out the DSA parameters in human readable form.

=item B<-C>

this option converts the parameters into C code. The parameters can then
be loaded by calling the B<get_dsaXXX()> function.

=item B<-genkey>

this option will generate a DSA either using the specified or generated
parameters.

=item B<-rand file(s)>

a file or files containing random data used to seed the random number
generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>).
Multiple files can be specified separated by a OS-dependent character.
The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
all others.

=item B<numbits>

this option specifies that a parameter set should be generated of size
B<numbits>. It must be the last option. If this option is included then
the input file (if any) is ignored.

=item B<-engine id>

specifying an engine (by it's unique B<id> string) will cause B<req>
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

PEM format DSA parameters use the header and footer lines:

 -----BEGIN DSA PARAMETERS-----
 -----END DSA PARAMETERS-----

DSA parameter generation is a slow process and as a result the same set of
DSA parameters is often used to generate several distinct keys.

=head1 SEE ALSO

L<gendsa(1)|gendsa(1)>, L<dsa(1)|dsa(1)>, L<genrsa(1)|genrsa(1)>,
L<rsa(1)|rsa(1)>

=cut