NAME

       ec - EC key processing

SYNOPSIS

       openssl ec [-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] [-engine id]

DESCRIPTION

       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 a OpenSSL EC private key into the PKCS#8 private key format use the
       pkcs8 command.

COMMAND OPTIONS

       -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 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.

       -modulus
           this option prints out the value of the public key component 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 a 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.

       -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.

NOTES

       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-----

EXAMPLES

       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

       ecparam(1), dsa(1), rsa(1)

HISTORY

       The ec command was first introduced in OpenSSL 0.9.8.

AUTHOR

       Nils Larsch for the OpenSSL project (http://www.openssl.org).

1.0.1f                                             2018-12-04                                           EC(1SSL)