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).
