openssl-ecparam - EC parameter manipulation and generation
openssl ecparam [-help] [-inform
DER|PEM] [-outform DER|PEM] [-in
filename] [-out filename] [-noout]
[-text] [-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] [-propquery propq]
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.
- -help
- Print out a usage message.
- -inform
DER|PEM
- The EC parameters input format; unspecified by default. See
openssl-format-options(1) for details.
- -outform
DER|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.
- -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.
- -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 "Engine Options" in openssl(1). This option is
deprecated.
- -rand files,
-writerand file
- See "Random State Options" in openssl(1) for
details.
- -provider
name
- -provider-path
path
- -propquery
propq
- 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.
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.
Copyright 2003-2021 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>.