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:
