openssl-ec, ec - EC key processing
openssl ec [-help] [-inform PEM|DER] [-outform
  PEM|DER] [-in filename] [-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]
The ec 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 pkcs8 command.
  - -help
- Print out a usage message.
- -inform DER|PEM
- This specifies the input format. The DER option with a private key
      uses an ASN.1 DER encoded SEC1 private key. When used with a public key it
      uses the SubjectPublicKeyInfo structure as specified in RFC 3280. The
      PEM form is the default format: it consists of the DER
      format base64 encoded with additional header and footer lines. In the case
      of a private key PKCS#8 format is also accepted.
- -outform DER|PEM
- This specifies the output format, the options have the same meaning and
      default as the -inform option.
- -in filename
- This specifies the input filename 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.
- -passin arg
- The input file password source. For more information about the format of
      arg see the PASS PHRASE ARGUMENTS section in
      openssl(1).
- -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.
- -passout arg
- The output file password source. For more information about the format of
      arg see the PASS PHRASE ARGUMENTS section in
      openssl(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 the ec utility 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.
- -pubin
- By default, a private key is read from the input file. With this option a
      public key is read instead.
- -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
- This specifies how the points on the elliptic curve are converted into
      octet strings. Possible values are: compressed (the default value),
      uncompressed 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
- Specifying an engine (by its unique id string) will cause ec
      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.
The PEM private key format uses the header and footer lines:
 -----BEGIN EC PRIVATE KEY-----
 -----END EC PRIVATE KEY-----
The PEM public key format uses the header and footer lines:
 -----BEGIN PUBLIC KEY-----
 -----END PUBLIC KEY-----
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
ecparam(1), dsa(1), rsa(1)
Copyright 2003-2019 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the OpenSSL license (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>.