1=pod 2{- OpenSSL::safe::output_do_not_edit_headers(); -} 3 4=head1 NAME 5 6openssl-ecparam - EC parameter manipulation and generation 7 8=head1 SYNOPSIS 9 10B<openssl ecparam> 11[B<-help>] 12[B<-inform> B<DER>|B<PEM>] 13[B<-outform> B<DER>|B<PEM>] 14[B<-in> I<filename>] 15[B<-out> I<filename>] 16[B<-noout>] 17[B<-text>] 18[B<-check>] 19[B<-check_named>] 20[B<-name> I<arg>] 21[B<-list_curves>] 22[B<-conv_form> I<arg>] 23[B<-param_enc> I<arg>] 24[B<-no_seed>] 25[B<-genkey>] 26{- $OpenSSL::safe::opt_engine_synopsis -}{- $OpenSSL::safe::opt_r_synopsis -} 27{- $OpenSSL::safe::opt_provider_synopsis -} 28 29=head1 DESCRIPTION 30 31This command is used to manipulate or generate EC parameter files. 32 33OpenSSL is currently not able to generate new groups and therefore 34this command can only create EC parameters from known (named) curves. 35 36=head1 OPTIONS 37 38=over 4 39 40=item B<-help> 41 42Print out a usage message. 43 44=item B<-inform> B<DER>|B<PEM> 45 46The EC parameters input format; unspecified by default. 47See L<openssl-format-options(1)> for details. 48 49=item B<-outform> B<DER>|B<PEM> 50 51The EC parameters output format; the default is B<PEM>. 52See L<openssl-format-options(1)> for details. 53 54Parameters are encoded as B<EcpkParameters> as specified in IETF RFC 3279. 55 56=item B<-in> I<filename> 57 58This specifies the input filename to read parameters from or standard input if 59this option is not specified. 60 61=item B<-out> I<filename> 62 63This specifies the output filename parameters to. Standard output is used 64if this option is not present. The output filename should B<not> be the same 65as the input filename. 66 67=item B<-noout> 68 69This option inhibits the output of the encoded version of the parameters. 70 71=item B<-text> 72 73This option prints out the EC parameters in human readable form. 74 75=item B<-check> 76 77Validate the elliptic curve parameters. 78 79=item B<-check_named> 80 81Validate the elliptic name curve parameters by checking if the curve parameters 82match any built-in curves. 83 84=item B<-name> I<arg> 85 86Use the EC parameters with the specified 'short' name. Use B<-list_curves> 87to get a list of all currently implemented EC parameters. 88 89=item B<-list_curves> 90 91Print out a list of all currently implemented EC parameters names and exit. 92 93=item B<-conv_form> I<arg> 94 95This specifies how the points on the elliptic curve are converted 96into octet strings. Possible values are: B<compressed>, B<uncompressed> (the 97default value) and B<hybrid>. For more information regarding 98the point conversion forms please read the X9.62 standard. 99B<Note> Due to patent issues the B<compressed> option is disabled 100by default for binary curves and can be enabled by defining 101the preprocessor macro B<OPENSSL_EC_BIN_PT_COMP> at compile time. 102 103=item B<-param_enc> I<arg> 104 105This specifies how the elliptic curve parameters are encoded. 106Possible value are: B<named_curve>, i.e. the ec parameters are 107specified by an OID, or B<explicit> where the ec parameters are 108explicitly given (see RFC 3279 for the definition of the 109EC parameters structures). The default value is B<named_curve>. 110B<Note> the B<implicitlyCA> alternative, as specified in RFC 3279, 111is currently not implemented in OpenSSL. 112 113=item B<-no_seed> 114 115This option inhibits that the 'seed' for the parameter generation 116is included in the ECParameters structure (see RFC 3279). 117 118=item B<-genkey> 119 120This option will generate an EC private key using the specified parameters. 121 122{- $OpenSSL::safe::opt_engine_item -} 123 124{- $OpenSSL::safe::opt_r_item -} 125 126{- $OpenSSL::safe::opt_provider_item -} 127 128=back 129 130The L<openssl-genpkey(1)> and L<openssl-pkeyparam(1)> commands are capable 131of performing all the operations this command can, as well as supporting 132other public key types. 133 134=head1 EXAMPLES 135 136The documentation for the L<openssl-genpkey(1)> and L<openssl-pkeyparam(1)> 137commands contains examples equivalent to the ones listed here. 138 139To create EC parameters with the group 'prime192v1': 140 141 openssl ecparam -out ec_param.pem -name prime192v1 142 143To create EC parameters with explicit parameters: 144 145 openssl ecparam -out ec_param.pem -name prime192v1 -param_enc explicit 146 147To validate given EC parameters: 148 149 openssl ecparam -in ec_param.pem -check 150 151To create EC parameters and a private key: 152 153 openssl ecparam -out ec_key.pem -name prime192v1 -genkey 154 155To change the point encoding to 'compressed': 156 157 openssl ecparam -in ec_in.pem -out ec_out.pem -conv_form compressed 158 159To print out the EC parameters to standard output: 160 161 openssl ecparam -in ec_param.pem -noout -text 162 163=head1 SEE ALSO 164 165L<openssl(1)>, 166L<openssl-pkeyparam(1)>, 167L<openssl-genpkey(1)>, 168L<openssl-ec(1)>, 169L<openssl-dsaparam(1)> 170 171=head1 HISTORY 172 173The B<-engine> option was deprecated in OpenSSL 3.0. 174 175The B<-C> option was removed in OpenSSL 3.0. 176 177=head1 COPYRIGHT 178 179Copyright 2003-2021 The OpenSSL Project Authors. All Rights Reserved. 180 181Licensed under the Apache License 2.0 (the "License"). You may not use 182this file except in compliance with the License. You can obtain a copy 183in the file LICENSE in the source distribution or at 184L<https://www.openssl.org/source/license.html>. 185 186=cut 187
