=pod =head1 NAME dhparam - DH parameter manipulation and generation =head1 SYNOPSIS B [B<-inform DER|PEM>] [B<-outform DER|PEM>] [B<-in filename>] [B<-out filename>] [B<-noout>] [B<-text>] [B<-C>] [B<-2>] [B<-5>] [B<-rand file(s)>] [numbits] =head1 DESCRIPTION This command is used to manipulate DH parameter files. =head1 OPTIONS =over 4 =item B<-inform DER|PEM> This specifies the input format. The B option uses an ASN1 DER encoded form compatible with the PKCS#3 DHparameter structure. The PEM form is the default format: it consists of the B 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. =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 be the same as the input filename. =item B<-2>, B<-5> The generator to use, either 2 or 5. 2 is the default. If present then the input file is ignored and parameters are generated instead. =item B<-rand file(s)> a file or files containing random data used to seed the random number generator. Multiple files can be specified separated by a OS-dependent character. For MS-Windows, the separator is B<;>. For OpenVMS, it's B<,>. For all others, it's B<:>. =item B this option specifies that a parameter set should be generated of size B. It must be the last option. If not present then a value of 512 is used. If this option is present then the input file is ignored and parameters are generated instead. =item B<-noout> this option inhibits the output of the encoded version of the parameters. =item B<-text> this option prints out the DH 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 function. =back =head1 WARNINGS The program B combines the functionality of the programs B and B in previous versions of OpenSSL and SSLeay. The B and B programs are retained for now but may have different purposes in future versions of OpenSSL. =head1 NOTES PEM format DH parameters use the header and footer lines: -----BEGIN DH PARAMETERS----- -----END DH PARAMETERS----- OpenSSL currently only supports the older PKCS#3 DH, not the newer X9.42 DH. This program manipulates DH parameters not keys. =head1 BUGS There should be a way to generate and manipulate DH keys. =head1 SEE ALSO L =cut