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EC(1)                        OpenSSL                        EC(1)


NAME

     openssl-ec, 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

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EC(1)                        OpenSSL                        EC(1)

         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

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EC(1)                        OpenSSL                        EC(1)

         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)

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EC(1)                        OpenSSL                        EC(1)


HISTORY

     The ec command was first introduced in OpenSSL 0.9.8.


AUTHOR

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

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See also openssl-ec(1)

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