openssl-ecparam - EC parameter manipulation and generation

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       Licensed  under  the  Apache License 2.0 (the "License").  You may not use this file except in compliance
       with the License.  You can obtain  a  copy  in  the  file  LICENSE  in  the  source  distribution  or  at
       <https://www.openssl.org/source/license.html>.

3.4.1                                              2025-04-03                              OPENSSL-ECPARAM(1SSL)

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

       OpenSSL is currently not able to generate new groups and therefore this command can only create EC
       parameters from known (named) curves.

       The  documentation  for  the  openssl-genpkey(1)  and  openssl-pkeyparam(1)  commands  contains  examples
       equivalent to the ones listed here.

       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

       The -engine option was deprecated in OpenSSL 3.0.

       The -C option was removed in OpenSSL 3.0.

       openssl-ecparam - EC parameter manipulation and generation

-help
           Print out a usage message.

       -informDER|PEM
           The EC parameters input format; unspecified by default.  See openssl-format-options(1) for details.

       -outformDER|PEM
           The EC parameters output format; the default is PEM.  See openssl-format-options(1) for details.

           Parameters are encoded as EcpkParameters as specified in IETF RFC 3279.

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

       -outfilename
           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.

       -check
           Validate the elliptic curve parameters.

       -check_named
           Validate  the  elliptic  name curve parameters by checking if the curve parameters match any built-in
           curves.

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

       -list_curves
           Print out a list of all currently implemented EC parameters names and exit.

       -conv_formarg
           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_encarg
           This  specifies how the elliptic curve parameters are encoded.  Possible value are: named_curve, i.e.
           the ec parameters are specified by an 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 an EC private key using the specified parameters.

       -engineid
           See "Engine Options" in openssl(1).  This option is deprecated.

       -randfiles, -writerandfile
           See "Random State Options" in openssl(1) for details.

       -providername-provider-pathpath-propquerypropq
           See "Provider Options" in openssl(1), provider(7), and property(7).

       The  openssl-genpkey(1)  and  openssl-pkeyparam(1)  commands are capable of performing all the operations
       this command can, as well as supporting other public key types.

openssl(1), openssl-pkeyparam(1), openssl-genpkey(1), openssl-ec(1), openssl-dsaparam(1)

opensslecparam [-help] [-informDER|PEM] [-outformDER|PEM] [-infilename] [-outfilename] [-noout]
       [-text] [-check] [-check_named] [-namearg] [-list_curves] [-conv_formarg] [-param_encarg] [-no_seed]
       [-genkey] [-engineid] [-randfiles] [-writerandfile] [-providername] [-provider-pathpath] [-propquerypropq]