NAME

       ecparam - EC parameter manipulation and generation

SYNOPSIS

       openssl ecparam [-inform DER|PEM] [-outform DER|PEM] [-in filename] [-out filename]
       [-noout] [-text] [-C] [-check] [-name arg] [-list_curve] [-conv_form arg] [-param_enc arg]
       [-no_seed] [-rand file(s)] [-genkey] [-engine id]

DESCRIPTION

       This command is used to manipulate or generate EC parameter files.

OPTIONS

       -inform DER|PEM
           This specifies the input format. The 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 DER format base64 encoded with additional header and footer lines.

       -outform DER|PEM
           This specifies the output format, the options have the same meaning as the -inform
           option.

       -in filename
           This specifies the input filename to read parameters from or standard input if this
           option is not specified.

       -out filename
           This specifies the output filename parameters to. Standard output is used if this
           option is not present. The output filename should not be the same as the input
           filename.

       -noout
           This option inhibits the output of the encoded version of the parameters.

       -text
           This option prints out the EC parameters in human readable form.

       -C  This option converts the EC parameters into C code. The parameters can then be loaded
           by calling the get_ec_group_XXX() function.

       -check
           Validate the elliptic curve parameters.

       -name arg
           Use the EC parameters with the specified 'short' name. Use -list_curves to get a list
           of all currently implemented EC parameters.

       -list_curves
           If this options is specified ecparam will print out a list of all currently
           implemented EC parameters names and exit.

       -conv_form
           This specifies how the points on the elliptic curve are converted into octet strings.
           Possible values are: compressed (the default value), uncompressed and hybrid. For more
           information regarding the point conversion forms please read the X9.62 standard.  Note
           Due to patent issues the compressed option is disabled by default for binary curves
           and can be enabled by defining the preprocessor macro OPENSSL_EC_BIN_PT_COMP at
           compile time.

       -param_enc arg
           This specifies how the elliptic curve parameters are encoded.  Possible value are:
           named_curve, i.e. the ec parameters are specified by a OID, or explicit where the ec
           parameters are explicitly given (see RFC 3279 for the definition of the EC parameters
           structures). The default value is named_curve.  Note the implicitlyCA alternative ,as
           specified in RFC 3279, is currently not implemented in OpenSSL.

       -no_seed
           This option inhibits that the 'seed' for the parameter generation is included in the
           ECParameters structure (see RFC 3279).

       -genkey
           This option will generate a EC private key using the specified parameters.

       -rand file(s)
           a file or files containing random data used to seed the random number generator, or an
           EGD socket (see RAND_egd(3)).  Multiple files can be specified separated by a OS-
           dependent character.  The separator is ; for MS-Windows, , for OpenVMS, and : for all
           others.

       -engine id
           specifying an engine (by its unique id string) will cause 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.

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 ecparam can only create
       EC parameters from known (named) curves.

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

SEE ALSO

       ec(1), dsaparam(1)

HISTORY

       The ecparam command was first introduced in OpenSSL 0.9.8.

AUTHOR

       Nils Larsch for the OpenSSL project (http://www.openssl.org)