/usr/man/cat.1/ecparam.1(/usr/man/cat.1/ecparam.1)

ECPARAM(1)                   OpenSSL                   ECPARAM(1)

NAME

     openssl-ecparam, 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_curves] [-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
         ggeett_eecc_ggrroouupp_XXXXXX(()) function.

     -check
         Validate the elliptic curve parameters.

     -name arg

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ECPARAM(1)                   OpenSSL                   ECPARAM(1)

         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, uncompressed (the default value) 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.

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ECPARAM(1)                   OpenSSL                   ECPARAM(1)

     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.

     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

     ec(1), dsaparam(1)

     The ecparam command was first introduced in OpenSSL 0.9.8.

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

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See also openssl-ecparam(1)