ecparam.pod revision 331638
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<-inform DER|PEM>] 12[B<-outform DER|PEM>] 13[B<-in filename>] 14[B<-out filename>] 15[B<-noout>] 16[B<-text>] 17[B<-C>] 18[B<-check>] 19[B<-name arg>] 20[B<-list_curves>] 21[B<-conv_form arg>] 22[B<-param_enc arg>] 23[B<-no_seed>] 24[B<-rand file(s)>] 25[B<-genkey>] 26[B<-engine id>] 27 28=head1 DESCRIPTION 29 30This command is used to manipulate or generate EC parameter files. 31 32=head1 OPTIONS 33 34=over 4 35 36=item B<-inform DER|PEM> 37 38This specifies the input format. The B<DER> option uses an ASN.1 DER encoded 39form compatible with RFC 3279 EcpkParameters. The PEM form is the default 40format: it consists of the B<DER> format base64 encoded with additional 41header and footer lines. 42 43=item B<-outform DER|PEM> 44 45This specifies the output format, the options have the same meaning as the 46B<-inform> option. 47 48=item B<-in filename> 49 50This specifies the input filename to read parameters from or standard input if 51this option is not specified. 52 53=item B<-out filename> 54 55This specifies the output filename parameters to. Standard output is used 56if this option is not present. The output filename should B<not> be the same 57as the input filename. 58 59=item B<-noout> 60 61This option inhibits the output of the encoded version of the parameters. 62 63=item B<-text> 64 65This option prints out the EC parameters in human readable form. 66 67=item B<-C> 68 69This option converts the EC parameters into C code. The parameters can then 70be loaded by calling the B<get_ec_group_XXX()> function. 71 72=item B<-check> 73 74Validate the elliptic curve parameters. 75 76=item B<-name arg> 77 78Use the EC parameters with the specified 'short' name. Use B<-list_curves> 79to get a list of all currently implemented EC parameters. 80 81=item B<-list_curves> 82 83If this options is specified B<ecparam> will print out a list of all 84currently implemented EC parameters names and exit. 85 86=item B<-conv_form> 87 88This specifies how the points on the elliptic curve are converted 89into octet strings. Possible values are: B<compressed>, B<uncompressed> (the 90default value) and B<hybrid>. For more information regarding 91the point conversion forms please read the X9.62 standard. 92B<Note> Due to patent issues the B<compressed> option is disabled 93by default for binary curves and can be enabled by defining 94the preprocessor macro B<OPENSSL_EC_BIN_PT_COMP> at compile time. 95 96=item B<-param_enc arg> 97 98This specifies how the elliptic curve parameters are encoded. 99Possible value are: B<named_curve>, i.e. the ec parameters are 100specified by a OID, or B<explicit> where the ec parameters are 101explicitly given (see RFC 3279 for the definition of the 102EC parameters structures). The default value is B<named_curve>. 103B<Note> the B<implicitlyCA> alternative ,as specified in RFC 3279, 104is currently not implemented in OpenSSL. 105 106=item B<-no_seed> 107 108This option inhibits that the 'seed' for the parameter generation 109is included in the ECParameters structure (see RFC 3279). 110 111=item B<-genkey> 112 113This option will generate a EC private key using the specified parameters. 114 115=item B<-rand file(s)> 116 117a file or files containing random data used to seed the random number 118generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>). 119Multiple files can be specified separated by a OS-dependent character. 120The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for 121all others. 122 123=item B<-engine id> 124 125specifying an engine (by its unique B<id> string) will cause B<ecparam> 126to attempt to obtain a functional reference to the specified engine, 127thus initialising it if needed. The engine will then be set as the default 128for all available algorithms. 129 130=back 131 132=head1 NOTES 133 134PEM format EC parameters use the header and footer lines: 135 136 -----BEGIN EC PARAMETERS----- 137 -----END EC PARAMETERS----- 138 139OpenSSL is currently not able to generate new groups and therefore 140B<ecparam> can only create EC parameters from known (named) curves. 141 142=head1 EXAMPLES 143 144To create EC parameters with the group 'prime192v1': 145 146 openssl ecparam -out ec_param.pem -name prime192v1 147 148To create EC parameters with explicit parameters: 149 150 openssl ecparam -out ec_param.pem -name prime192v1 -param_enc explicit 151 152To validate given EC parameters: 153 154 openssl ecparam -in ec_param.pem -check 155 156To create EC parameters and a private key: 157 158 openssl ecparam -out ec_key.pem -name prime192v1 -genkey 159 160To change the point encoding to 'compressed': 161 162 openssl ecparam -in ec_in.pem -out ec_out.pem -conv_form compressed 163 164To print out the EC parameters to standard output: 165 166 openssl ecparam -in ec_param.pem -noout -text 167 168=head1 SEE ALSO 169 170L<ec(1)|ec(1)>, L<dsaparam(1)|dsaparam(1)> 171 172=head1 HISTORY 173 174The ecparam command was first introduced in OpenSSL 0.9.8. 175 176=head1 AUTHOR 177 178Nils Larsch for the OpenSSL project (http://www.openssl.org) 179 180=cut 181