=pod =head1 NAME ecparam - EC parameter manipulation and generation =head1 SYNOPSIS B<openssl ecparam> [B<-inform DER|PEM>] [B<-outform DER|PEM>] [B<-in filename>] [B<-out filename>] [B<-noout>] [B<-text>] [B<-C>] [B<-check>] [B<-name arg>] [B<-list_curve>] [B<-conv_form arg>] [B<-param_enc arg>] [B<-no_seed>] [B<-rand file(s)>] [B<-genkey>] [B<-engine id>] =head1 DESCRIPTION This command is used to manipulate or generate EC parameter files. =head1 OPTIONS =over 4 =item B<-inform DER|PEM> This specifies the input format. The B<DER> option uses an ASN.1 DER encoded form compatible with RFC 3279 EcpkParameters. The PEM form is the default format: it consists of the B<DER> format base64 encoded with additional header and footer lines. =item B<-outform DER|PEM> This specifies the output format, the options have the same meaning as the B<-inform> option. =item B<-in filename> This specifies the input filename to read parameters from or standard input if this option is not specified. =item B<-out filename> This specifies the output filename parameters to. Standard output is used if this option is not present. The output filename should B<not> be the same as the input filename. =item B<-noout> This option inhibits the output of the encoded version of the parameters. =item B<-text> This option prints out the EC parameters in human readable form. =item B<-C> This option converts the EC parameters into C code. The parameters can then be loaded by calling the B<get_ec_group_XXX()> function. =item B<-check> Validate the elliptic curve parameters. =item B<-name arg> Use the EC parameters with the specified 'short' name. Use B<-list_curves> to get a list of all currently implemented EC parameters. =item B<-list_curves> If this options is specified B<ecparam> will print out a list of all currently implemented EC parameters names and exit. =item B<-conv_form> This specifies how the points on the elliptic curve are converted into octet strings. Possible values are: B<compressed> (the default value), B<uncompressed> and B<hybrid>. For more information regarding the point conversion forms please read the X9.62 standard. B<Note> Due to patent issues the B<compressed> option is disabled by default for binary curves and can be enabled by defining the preprocessor macro B<OPENSSL_EC_BIN_PT_COMP> at compile time. =item B<-param_enc arg> This specifies how the elliptic curve parameters are encoded. Possible value are: B<named_curve>, i.e. the ec parameters are specified by a OID, or B<explicit> where the ec parameters are explicitly given (see RFC 3279 for the definition of the EC parameters structures). The default value is B<named_curve>. B<Note> the B<implicitlyCA> alternative ,as specified in RFC 3279, is currently not implemented in OpenSSL. =item B<-no_seed> This option inhibits that the 'seed' for the parameter generation is included in the ECParameters structure (see RFC 3279). =item B<-genkey> This option will generate a EC private key using the specified parameters. =item B<-rand file(s)> a file or files containing random data used to seed the random number generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>). Multiple files can be specified separated by a OS-dependent character. The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for all others. =item B<-engine id> specifying an engine (by its unique B<id> string) will cause B<ecparam> to attempt to obtain a functional reference to the specified engine, thus initialising it if needed. The engine will then be set as the default for all available algorithms. =back =head1 NOTES PEM format EC parameters use the header and footer lines: -----BEGIN EC PARAMETERS----- -----END EC PARAMETERS----- OpenSSL is currently not able to generate new groups and therefore B<ecparam> can only create EC parameters from known (named) curves. =head1 EXAMPLES To create EC parameters with the group 'prime192v1': openssl ecparam -out ec_param.pem -name prime192v1 To create EC parameters with explicit parameters: openssl ecparam -out ec_param.pem -name prime192v1 -param_enc explicit To validate given EC parameters: openssl ecparam -in ec_param.pem -check To create EC parameters and a private key: openssl ecparam -out ec_key.pem -name prime192v1 -genkey To change the point encoding to 'compressed': openssl ecparam -in ec_in.pem -out ec_out.pem -conv_form compressed To print out the EC parameters to standard output: openssl ecparam -in ec_param.pem -noout -text =head1 SEE ALSO L<ec(1)|ec(1)>, L<dsaparam(1)|dsaparam(1)> =head1 HISTORY The ecparam command was first introduced in OpenSSL 0.9.8. =head1 AUTHOR Nils Larsch for the OpenSSL project (http://www.openssl.org) =cut