OPENSSL-EC(1SSL) OpenSSL OPENSSL-EC(1SSL)
NAME
openssl-ec - EC key processing
SYNOPSIS
openssl ec [-help] [-inform DER|PEM|P12|ENGINE] [-outform DER|PEM] [-in
filename|uri] [-passin arg] [-out filename] [-passout arg] [-des]
[-des3] [-idea] [-text] [-noout] [-param_out] [-pubin] [-pubout]
[-conv_form arg] [-param_enc arg] [-no_public] [-check] [-engine id]
[-provider name] [-provider-path path] [-provparam [name:]key=value]
[-propquery propq]
DESCRIPTION
The openssl-ec(1) command processes EC keys. They can be converted
between various forms and their components printed out. Note OpenSSL
uses the private key format specified in 'SEC 1: Elliptic Curve
Cryptography' (http://www.secg.org/). To convert an OpenSSL EC private
key into the PKCS#8 private key format use the openssl-pkcs8(1) command.
OPTIONS
-help
Print out a usage message.
-inform DER|PEM|P12|ENGINE
The key input format; unspecified by default. See
openssl-format-options(1) for details.
-outform DER|PEM
The key output format; the default is PEM. See
openssl-format-options(1) for details.
Private keys are an SEC1 private key or PKCS#8 format. Public keys
are a SubjectPublicKeyInfo as specified in IETF RFC 3280.
-in filename|uri
This specifies the input to read a key from or standard input if
this option is not specified. If the key is encrypted a pass phrase
will be prompted for.
-out filename
This specifies the output filename to write a key to or standard
output by is not specified. If any encryption options are set then a
pass phrase will be prompted for. The output filename should not be
the same as the input filename.
-passin arg, -passout arg
The password source for the input and output file. For more
information about the format of arg see
openssl-passphrase-options(1).
-des|-des3|-idea
These options encrypt the private key with the DES, triple DES, IDEA
or any other cipher supported by OpenSSL before outputting it. A
pass phrase is prompted for. If none of these options is specified
the key is written in plain text. This means that using this command
to read in an encrypted key with no encryption option can be used to
remove the pass phrase from a key, or by setting the encryption
options it can be use to add or change the pass phrase. These
options can only be used with PEM format output files.
-text
Prints out the public, private key components and parameters.
-noout
This option prevents output of the encoded version of the key.
-param_out
Print the elliptic curve parameters.
-pubin
By default a private key is read from the input. With this option a
public key is read instead. If the input contains no public key but
a private key, its public part is used.
-pubout
By default a private key is output. With this option a public key
will be output instead. This option is automatically set if the
input is a public key.
-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_public
This option omits the public key components from the private key
output.
-check
This option checks the consistency of an EC private or public key.
-engine id
See "Engine Options" in openssl(1). This option is deprecated.
-provider name
-provider-path path
-provparam [name:]key=value
-propquery propq
See "Provider Options" in openssl(1), provider(7), and property(7).
The openssl-pkey(1) command is capable of performing all the operations
this command can, as well as supporting other public key types.
EXAMPLES
The documentation for the openssl-pkey(1) command contains examples
equivalent to the ones listed here.
To encrypt a private key using triple DES:
openssl ec -in key.pem -des3 -out keyout.pem
To convert a private key from PEM to DER format:
openssl ec -in key.pem -outform DER -out keyout.der
To print out the components of a private key to standard output:
openssl ec -in key.pem -text -noout
To just output the public part of a private key:
openssl ec -in key.pem -pubout -out pubkey.pem
To change the parameters encoding to explicit:
openssl ec -in key.pem -param_enc explicit -out keyout.pem
To change the point conversion form to compressed:
openssl ec -in key.pem -conv_form compressed -out keyout.pem
SEE ALSO
openssl(1), openssl-pkey(1), openssl-ecparam(1), openssl-dsa(1),
openssl-rsa(1)
HISTORY
The -engine option was deprecated in OpenSSL 3.0.
The -conv_form and -no_public options are no longer supported with keys
loaded from an engine in OpenSSL 3.0.
COPYRIGHT
Copyright 2003-2023 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>.
3.5.4 2025-09-30 OPENSSL-EC(1SSL)
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