1=pod 2 3=head1 NAME 4 5ecparam - EC parameter manipulation and generation 6 7=head1 SYNOPSIS 8 9B<openssl ecparam> 10[B<-inform DER|PEM>] 11[B<-outform DER|PEM>] 12[B<-in filename>] 13[B<-out filename>] 14[B<-noout>] 15[B<-text>] 16[B<-C>] 17[B<-check>] 18[B<-name arg>] 19[B<-list_curves>] 20[B<-conv_form arg>] 21[B<-param_enc arg>] 22[B<-no_seed>] 23[B<-rand file(s)>] 24[B<-genkey>] 25[B<-engine id>] 26 27=head1 DESCRIPTION 28 29This command is used to manipulate or generate EC parameter files. 30 31=head1 OPTIONS 32 33=over 4 34 35=item B<-inform DER|PEM> 36 37This specifies the input format. The B<DER> option uses an ASN.1 DER encoded 38form compatible with RFC 3279 EcpkParameters. The PEM form is the default 39format: it consists of the B<DER> format base64 encoded with additional 40header and footer lines. 41 42=item B<-outform DER|PEM> 43 44This specifies the output format, the options have the same meaning as the 45B<-inform> option. 46 47=item B<-in filename> 48 49This specifies the input filename to read parameters from or standard input if 50this option is not specified. 51 52=item B<-out filename> 53 54This specifies the output filename parameters to. Standard output is used 55if this option is not present. The output filename should B<not> be the same 56as the input filename. 57 58=item B<-noout> 59 60This option inhibits the output of the encoded version of the parameters. 61 62=item B<-text> 63 64This option prints out the EC parameters in human readable form. 65 66=item B<-C> 67 68This option converts the EC parameters into C code. The parameters can then 69be loaded by calling the B<get_ec_group_XXX()> function. 70 71=item B<-check> 72 73Validate the elliptic curve parameters. 74 75=item B<-name arg> 76 77Use the EC parameters with the specified 'short' name. Use B<-list_curves> 78to get a list of all currently implemented EC parameters. 79 80=item B<-list_curves> 81 82If this options is specified B<ecparam> will print out a list of all 83currently implemented EC parameters names and exit. 84 85=item B<-conv_form> 86 87This specifies how the points on the elliptic curve are converted 88into octet strings. Possible values are: B<compressed> (the default 89value), B<uncompressed> and B<hybrid>. For more information regarding 90the point conversion forms please read the X9.62 standard. 91B<Note> Due to patent issues the B<compressed> option is disabled 92by default for binary curves and can be enabled by defining 93the preprocessor macro B<OPENSSL_EC_BIN_PT_COMP> at compile time. 94 95=item B<-param_enc arg> 96 97This specifies how the elliptic curve parameters are encoded. 98Possible value are: B<named_curve>, i.e. the ec parameters are 99specified by a OID, or B<explicit> where the ec parameters are 100explicitly given (see RFC 3279 for the definition of the 101EC parameters structures). The default value is B<named_curve>. 102B<Note> the B<implicitlyCA> alternative ,as specified in RFC 3279, 103is currently not implemented in OpenSSL. 104 105=item B<-no_seed> 106 107This option inhibits that the 'seed' for the parameter generation 108is included in the ECParameters structure (see RFC 3279). 109 110=item B<-genkey> 111 112This option will generate a EC private key using the specified parameters. 113 114=item B<-rand file(s)> 115 116a file or files containing random data used to seed the random number 117generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>). 118Multiple files can be specified separated by a OS-dependent character. 119The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for 120all others. 121 122=item B<-engine id> 123 124specifying an engine (by its unique B<id> string) will cause B<ecparam> 125to attempt to obtain a functional reference to the specified engine, 126thus initialising it if needed. The engine will then be set as the default 127for all available algorithms. 128 129=back 130 131=head1 NOTES 132 133PEM format EC parameters use the header and footer lines: 134 135 -----BEGIN EC PARAMETERS----- 136 -----END EC PARAMETERS----- 137 138OpenSSL is currently not able to generate new groups and therefore 139B<ecparam> can only create EC parameters from known (named) curves. 140 141=head1 EXAMPLES 142 143To create EC parameters with the group 'prime192v1': 144 145 openssl ecparam -out ec_param.pem -name prime192v1 146 147To create EC parameters with explicit parameters: 148 149 openssl ecparam -out ec_param.pem -name prime192v1 -param_enc explicit 150 151To validate given EC parameters: 152 153 openssl ecparam -in ec_param.pem -check 154 155To create EC parameters and a private key: 156 157 openssl ecparam -out ec_key.pem -name prime192v1 -genkey 158 159To change the point encoding to 'compressed': 160 161 openssl ecparam -in ec_in.pem -out ec_out.pem -conv_form compressed 162 163To print out the EC parameters to standard output: 164 165 openssl ecparam -in ec_param.pem -noout -text 166 167=head1 SEE ALSO 168 169L<ec(1)|ec(1)>, L<dsaparam(1)|dsaparam(1)> 170 171=head1 HISTORY 172 173The ecparam command was first introduced in OpenSSL 0.9.8. 174 175=head1 AUTHOR 176 177Nils Larsch for the OpenSSL project (http://www.openssl.org) 178 179=cut 180