EC(1)                                                        OpenSSL                                                       EC(1)



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 structur 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).



1.0.0e                                                     2009-04-10                                                      EC(1)