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 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.

       -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).



1.0.2k				  2023-11-15				 EC(1)