1=pod 2 3=head1 NAME 4 5openssl-ecparam, 6ecparam - EC parameter manipulation and generation 7 8=head1 SYNOPSIS 9 10B<openssl ecparam> 11[B<-help>] 12[B<-inform DER|PEM>] 13[B<-outform DER|PEM>] 14[B<-in filename>] 15[B<-out filename>] 16[B<-noout>] 17[B<-text>] 18[B<-C>] 19[B<-check>] 20[B<-name arg>] 21[B<-list_curves>] 22[B<-conv_form arg>] 23[B<-param_enc arg>] 24[B<-no_seed>] 25[B<-rand file...>] 26[B<-writerand file>] 27[B<-genkey>] 28[B<-engine id>] 29 30=head1 DESCRIPTION 31 32This command is used to manipulate or generate EC parameter files. 33 34=head1 OPTIONS 35 36=over 4 37 38=item B<-help> 39 40Print out a usage message. 41 42=item B<-inform DER|PEM> 43 44This specifies the input format. The B<DER> option uses an ASN.1 DER encoded 45form compatible with RFC 3279 EcpkParameters. The PEM form is the default 46format: it consists of the B<DER> format base64 encoded with additional 47header and footer lines. 48 49=item B<-outform DER|PEM> 50 51This specifies the output format, the options have the same meaning and default 52as the B<-inform> option. 53 54=item B<-in filename> 55 56This specifies the input filename to read parameters from or standard input if 57this option is not specified. 58 59=item B<-out filename> 60 61This specifies the output filename parameters to. Standard output is used 62if this option is not present. The output filename should B<not> be the same 63as the input filename. 64 65=item B<-noout> 66 67This option inhibits the output of the encoded version of the parameters. 68 69=item B<-text> 70 71This option prints out the EC parameters in human readable form. 72 73=item B<-C> 74 75This option converts the EC parameters into C code. The parameters can then 76be loaded by calling the get_ec_group_XXX() function. 77 78=item B<-check> 79 80Validate the elliptic curve parameters. 81 82=item B<-name arg> 83 84Use the EC parameters with the specified 'short' name. Use B<-list_curves> 85to get a list of all currently implemented EC parameters. 86 87=item B<-list_curves> 88 89If this options is specified B<ecparam> will print out a list of all 90currently implemented EC parameters names and exit. 91 92=item B<-conv_form> 93 94This specifies how the points on the elliptic curve are converted 95into octet strings. Possible values are: B<compressed>, B<uncompressed> (the 96default value) and B<hybrid>. For more information regarding 97the point conversion forms please read the X9.62 standard. 98B<Note> Due to patent issues the B<compressed> option is disabled 99by default for binary curves and can be enabled by defining 100the preprocessor macro B<OPENSSL_EC_BIN_PT_COMP> at compile time. 101 102=item B<-param_enc arg> 103 104This specifies how the elliptic curve parameters are encoded. 105Possible value are: B<named_curve>, i.e. the ec parameters are 106specified by an OID, or B<explicit> where the ec parameters are 107explicitly given (see RFC 3279 for the definition of the 108EC parameters structures). The default value is B<named_curve>. 109B<Note> the B<implicitlyCA> alternative, as specified in RFC 3279, 110is currently not implemented in OpenSSL. 111 112=item B<-no_seed> 113 114This option inhibits that the 'seed' for the parameter generation 115is included in the ECParameters structure (see RFC 3279). 116 117=item B<-genkey> 118 119This option will generate an EC private key using the specified parameters. 120 121=item B<-rand file...> 122 123A file or files containing random data used to seed the random number 124generator. 125Multiple files can be specified separated by an OS-dependent character. 126The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for 127all others. 128 129=item [B<-writerand file>] 130 131Writes random data to the specified I<file> upon exit. 132This can be used with a subsequent B<-rand> flag. 133 134=item B<-engine id> 135 136Specifying an engine (by its unique B<id> string) will cause B<ecparam> 137to attempt to obtain a functional reference to the specified engine, 138thus initialising it if needed. The engine will then be set as the default 139for all available algorithms. 140 141=back 142 143=head1 NOTES 144 145PEM format EC parameters use the header and footer lines: 146 147 -----BEGIN EC PARAMETERS----- 148 -----END EC PARAMETERS----- 149 150OpenSSL is currently not able to generate new groups and therefore 151B<ecparam> can only create EC parameters from known (named) curves. 152 153=head1 EXAMPLES 154 155To create EC parameters with the group 'prime192v1': 156 157 openssl ecparam -out ec_param.pem -name prime192v1 158 159To create EC parameters with explicit parameters: 160 161 openssl ecparam -out ec_param.pem -name prime192v1 -param_enc explicit 162 163To validate given EC parameters: 164 165 openssl ecparam -in ec_param.pem -check 166 167To create EC parameters and a private key: 168 169 openssl ecparam -out ec_key.pem -name prime192v1 -genkey 170 171To change the point encoding to 'compressed': 172 173 openssl ecparam -in ec_in.pem -out ec_out.pem -conv_form compressed 174 175To print out the EC parameters to standard output: 176 177 openssl ecparam -in ec_param.pem -noout -text 178 179=head1 SEE ALSO 180 181L<ec(1)>, L<dsaparam(1)> 182 183=head1 COPYRIGHT 184 185Copyright 2003-2018 The OpenSSL Project Authors. All Rights Reserved. 186 187Licensed under the OpenSSL license (the "License"). You may not use 188this file except in compliance with the License. You can obtain a copy 189in the file LICENSE in the source distribution or at 190L<https://www.openssl.org/source/license.html>. 191 192=cut 193