NAME
openssl-ecparam - EC parameter manipulation and generation
SYNOPSIS
openssl ecparam [-help] [-inform DER|PEM] [-outform DER|PEM] [-in filename] [-out filename] [-noout] [-text] [-C] [-check] [-check_named] [-name arg] [-list_curves] [-conv_form arg] [-param_enc arg] [-no_seed] [-genkey] [-engine id] [-rand files] [-writerand file] [-provider name] [-provider_path path]
DESCRIPTION
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.
OPTIONS
- -help
-
Print out a usage message.
- -inform DER|PEM, -outform DER|PEM
-
The input and formats; the default is PEM. See -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.
- -check_named
Validate the elliptic name curve parameters by checking if the curve parameters match any built-in curves.
- -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
Print out a list of all currently implemented EC parameters names and exit.
- -conv_form arg
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 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.
- -engine id
See -rand files, -writerand file
See -provider name
- -provider_path path
See EXAMPLES
Examples equivalent to these can be found in the documentation for the non-deprecated openssl-pkeyparam(1) commands.
To create EC parameters with the group 'prime192v1':
openssl ecparam -out ec_param.pem -name prime192v1To create EC parameters with explicit parameters:
openssl ecparam -out ec_param.pem -name prime192v1 -param_enc explicitTo validate given EC parameters:
openssl ecparam -in ec_param.pem -checkTo create EC parameters and a private key:
openssl ecparam -out ec_key.pem -name prime192v1 -genkeyTo change the point encoding to 'compressed':
openssl ecparam -in ec_in.pem -out ec_out.pem -conv_form compressedTo print out the EC parameters to standard output:
openssl ecparam -in ec_param.pem -noout -textSEE ALSO
openssl-pkeyparam(1), openssl-ec(1), COPYRIGHT
Copyright 2003-2020 The OpenSSL Project Authors. All Rights Reserved.
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.