ECPARAM(1)                          OpenSSL                         ECPARAM(1)



NNAAMMEE
       openssl-ecparam, ecparam - EC parameter manipulation and generation

SSYYNNOOPPSSIISS
       ooppeennssssll eeccppaarraamm [--iinnffoorrmm DDEERR||PPEEMM] [--oouuttffoorrmm DDEERR||PPEEMM] [--iinn ffiilleennaammee]
       [--oouutt ffiilleennaammee] [--nnoooouutt] [--tteexxtt] [--CC] [--cchheecckk] [--nnaammee aarrgg]
       [--lliisstt__ccuurrvveess] [--ccoonnvv__ffoorrmm aarrgg] [--ppaarraamm__eenncc aarrgg] [--nnoo__sseeeedd] [--rraanndd
       ffiillee((ss))] [--ggeennkkeeyy] [--eennggiinnee iidd]

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

OOPPTTIIOONNSS
       --iinnffoorrmm DDEERR||PPEEMM
           This specifies the input format. The DDEERR option uses an ASN.1 DER
           encoded form compatible with RFC 3279 EcpkParameters. The PEM form
           is the default format: it consists of the DDEERR format base64 encoded
           with additional header and footer lines.

       --oouuttffoorrmm DDEERR||PPEEMM
           This specifies the output format, the options have the same meaning
           as the --iinnffoorrmm option.

       --iinn ffiilleennaammee
           This specifies the input filename to read parameters from or stan-
           dard input if this option is not specified.

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

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

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

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

       --cchheecckk
           Validate the elliptic curve parameters.

       --nnaammee aarrgg
           Use the EC parameters with the specified 'short' name. Use
           --lliisstt__ccuurrvveess to get a list of all currently implemented EC parame-
           ters.

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

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

       --ppaarraamm__eenncc aarrgg
           This specifies how the elliptic curve parameters are encoded.  Pos-
           sible value are: nnaammeedd__ccuurrvvee, i.e. the ec parameters are specified
           by a OID, or eexxpplliicciitt where the ec parameters are explicitly given
           (see RFC 3279 for the definition of the EC parameters structures).
           The default value is nnaammeedd__ccuurrvvee.  NNoottee the iimmpplliicciittllyyCCAA alterna-
           tive ,as specified in RFC 3279, is currently not implemented in
           OpenSSL.

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

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

       --rraanndd ffiillee((ss))
           a file or files containing random data used to seed the random num-
           ber generator, or an EGD socket (see _R_A_N_D___e_g_d(3)).  Multiple files
           can be specified separated by a OS-dependent character.  The sepa-
           rator is ;; for MS-Windows, ,, for OpenVMS, and :: for all others.

       --eennggiinnee iidd
           specifying an engine (by its unique iidd string) will cause eeccppaarraamm
           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.

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

EEXXAAMMPPLLEESS
       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

SSEEEE AALLSSOO
       _e_c(1), _d_s_a_p_a_r_a_m(1)

HHIISSTTOORRYY
       The ecparam command was first introduced in OpenSSL 0.9.8.

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



1.0.2u                            2019-12-20                        ECPARAM(1)