5 dhparam - DH parameter manipulation and generation
24 This command is used to manipulate DH parameter files.
30 =item B<-inform DER|PEM>
32 This specifies the input format. The B<DER> option uses an ASN1 DER encoded
33 form compatible with the PKCS#3 DHparameter structure. The PEM form is the
34 default format: it consists of the B<DER> format base64 encoded with
35 additional header and footer lines.
37 =item B<-outform DER|PEM>
39 This specifies the output format, the options have the same meaning as the
44 This specifies the input filename to read parameters from or standard input if
45 this option is not specified.
47 =item B<-out filename>
49 This specifies the output filename parameters to. Standard output is used
50 if this option is not present. The output filename should B<not> be the same
51 as the input filename.
55 The generator to use, either 2 or 5. 2 is the default. If present then the
56 input file is ignored and parameters are generated instead.
58 =item B<-rand file(s)>
60 a file or files containing random data used to seed the random number
61 generator. Multiple files can be specified separated by a OS-dependent
62 character. For MS-Windows, the separator is B<;>. For OpenVMS, it's
63 B<,>. For all others, it's B<:>.
67 this option specifies that a parameter set should be generated of size
68 B<numbits>. It must be the last option. If not present then a value of 512
69 is used. If this option is present then the input file is ignored and
70 parameters are generated instead.
74 this option inhibits the output of the encoded version of the parameters.
78 this option prints out the DH parameters in human readable form.
82 this option converts the parameters into C code. The parameters can then
83 be loaded by calling the B<get_dhXXX()> function.
89 The program B<dhparam> combines the functionality of the programs B<dh> and
90 B<gendh> in previous versions of OpenSSL and SSLeay. The B<dh> and B<gendh>
91 programs are retained for now but may have different purposes in future
96 PEM format DH parameters use the header and footer lines:
98 -----BEGIN DH PARAMETERS-----
99 -----END DH PARAMETERS-----
101 OpenSSL currently only supports the older PKCS#3 DH, not the newer X9.42
104 This program manipulates DH parameters not keys.
108 There should be a way to generate and manipulate DH keys.
112 L<dsaparam(1)|dsaparam(1)>