NAME
EC_KEY_new,
EC_KEY_get_flags,
EC_KEY_set_flags,
EC_KEY_clear_flags,
EC_KEY_new_by_curve_name,
EC_KEY_free, EC_KEY_copy,
EC_KEY_dup, EC_KEY_up_ref,
EC_KEY_get0_group,
EC_KEY_set_group,
EC_KEY_get0_private_key,
EC_KEY_set_private_key,
EC_KEY_get0_public_key,
EC_KEY_set_public_key,
EC_KEY_get_enc_flags,
EC_KEY_set_enc_flags,
EC_KEY_get_conv_form,
EC_KEY_set_conv_form,
EC_KEY_set_asn1_flag,
EC_KEY_precompute_mult,
EC_KEY_generate_key,
EC_KEY_check_key,
EC_KEY_set_public_key_affine_coordinates,
EC_KEY_print,
EC_KEY_print_fp —
create, destroy and manipulate EC_KEY
objects
SYNOPSIS
#include
<openssl/ec.h>
#include <openssl/bn.h>
EC_KEY *
EC_KEY_new(void);
int
EC_KEY_get_flags(const EC_KEY
*key);
void
EC_KEY_set_flags(EC_KEY *key,
int flags);
void
EC_KEY_clear_flags(EC_KEY *key,
int flags);
EC_KEY *
EC_KEY_new_by_curve_name(int
nid);
void
EC_KEY_free(EC_KEY *key);
EC_KEY *
EC_KEY_copy(EC_KEY *dst,
const EC_KEY *src);
EC_KEY *
EC_KEY_dup(const EC_KEY
*src);
int
EC_KEY_up_ref(EC_KEY *key);
const EC_GROUP *
EC_KEY_get0_group(const EC_KEY
*key);
int
EC_KEY_set_group(EC_KEY *key,
const EC_GROUP *group);
const BIGNUM *
EC_KEY_get0_private_key(const EC_KEY
*key);
int
EC_KEY_set_private_key(EC_KEY
*key, const BIGNUM *prv);
const EC_POINT *
EC_KEY_get0_public_key(const EC_KEY
*key);
int
EC_KEY_set_public_key(EC_KEY
*key, const EC_POINT *pub);
unsigned int
EC_KEY_get_enc_flags(const EC_KEY
*key);
void
EC_KEY_set_enc_flags(EC_KEY
*key, unsigned int flags);
point_conversion_form_t
EC_KEY_get_conv_form(const EC_KEY
*key);
void
EC_KEY_set_conv_form(EC_KEY
*key, point_conversion_form_t cform);
void
EC_KEY_set_asn1_flag(EC_KEY
*key, int asn1_flag);
int
EC_KEY_precompute_mult(EC_KEY
*key, BN_CTX *ctx);
int
EC_KEY_generate_key(EC_KEY
*key);
int
EC_KEY_check_key(const EC_KEY
*key);
int
EC_KEY_set_public_key_affine_coordinates(EC_KEY
*key, BIGNUM *x, BIGNUM
*y);
int
EC_KEY_print(BIO *bp,
const EC_KEY *key, int off);
int
EC_KEY_print_fp(FILE *fp,
const EC_KEY *key, int off);
DESCRIPTION
An EC_KEY represents a public key and (optionally) an associated private key. The public key is a point on a curve represented by an EC_POINT, see EC_POINT_new(3). The private key is simply a BIGNUM, see BN_new(3).
A new EC_KEY (with no
associated curve) can be constructed by calling
EC_KEY_new().
The reference count for the newly created EC_KEY is
initially set to 1. A curve can be associated with the
EC_KEY by calling
EC_KEY_set_group().
Alternatively a new
EC_KEY can be constructed by calling
EC_KEY_new_by_curve_name()
and supplying the nid of the associated curve. Refer
to EC_GROUP_new(3) for a description of curve names. This function
simply wraps calls to EC_KEY_new() and
EC_GROUP_new_by_curve_name().
Calling
EC_KEY_free()
decrements the reference count for the EC_KEY object
and, if it has dropped to zero, then frees the memory associated with it. If
key is a NULL pointer, no
action occurs.
EC_KEY_copy()
copies the contents of the EC_KEY in
src into dst.
EC_KEY_dup()
creates a new EC_KEY object and copies
src into it.
EC_KEY_up_ref()
increments the reference count associated with the
EC_KEY object.
EC_KEY_generate_key()
generates a new public and private key for the supplied
key object. key must have an
EC_GROUP object associated with it before calling this
function. The private key is a random integer (0 < priv_key < order,
where order is the order of the EC_GROUP object). The
public key is an EC_POINT on the curve calculated by
multiplying the generator for the curve by the private key.
EC_KEY_check_key()
performs various sanity checks on the EC_KEY object to
confirm that it is valid.
EC_KEY_set_public_key_affine_coordinates()
sets the public key for key based on its affine
coordinates, i.e. it constructs an EC_POINT object
based on the supplied x and y
values and sets the public key to be this EC_POINT. It
also performs certain sanity checks on the key to confirm that it is
valid.
The functions
EC_KEY_get0_group(),
EC_KEY_set_group(),
EC_KEY_get0_private_key(),
EC_KEY_set_private_key(),
EC_KEY_get0_public_key(),
and
EC_KEY_set_public_key()
get and set the EC_GROUP object, the private key and
the EC_POINT public key for the
key, respectively. The setters copy the group and key
objects without sanity checks and it is the caller's responsibility to
ensure that the resulting key is valid, for example using
EC_KEY_check_key().
The functions
EC_KEY_get_enc_flags()
and
EC_KEY_set_enc_flags()
get and set the value of the encoding flags for the
key. There are two encoding flags currently defined:
EC_PKEY_NO_PARAMETERS and
EC_PKEY_NO_PUBKEY. These flags define the behaviour
of how the key is converted into ASN.1 in a call to
i2d_ECPrivateKey().
If EC_PKEY_NO_PARAMETERS is set then the public
parameters for the curve are not encoded along with the private key. If
EC_PKEY_NO_PUBKEY is set then the public key is not
encoded along with the private key.
The format of the external representation of the public key written by i2d_ECPrivateKey(3), such as whether it is stored in a compressed form or not, is described by the point_conversion_form. See EC_GROUP_copy(3) for a description of point_conversion_form.
When reading a private key encoded without an associated public
key, for example if EC_PKEY_NO_PUBKEY was used,
d2i_ECPrivateKey(3) generates the missing public key
automatically. Private keys encoded without parameters, for example if
EC_PKEY_NO_PARAMETERS was used, cannot be loaded
using d2i_ECPrivateKey(3).
The functions
EC_KEY_get_conv_form()
and
EC_KEY_set_conv_form()
get and set the point_conversion_form for the key. For
a description of point_conversion_form refer to
EC_GROUP_copy(3).
EC_KEY_set_flags()
sets the flags in the flags parameter on the
EC_KEY object. Any flags that are already set are left
set. The currently defined standard flags are
EC_FLAG_NON_FIPS_ALLOW and
EC_FLAG_FIPS_CHECKED. In addition there is the
ECDH-specific flag EC_FLAG_COFACTOR_ECDH.
EC_KEY_get_flags()
returns the current flags that are set for this
EC_KEY.
EC_KEY_clear_flags()
clears the flags indicated by the flags parameter. All
other flags are left in their existing state.
EC_KEY_set_asn1_flag()
sets the asn1_flag on the underlying EC_GROUP object
(if set). Refer to
EC_GROUP_copy(3) for further information on the asn1_flag.
EC_KEY_precompute_mult()
stores multiples of the underlying EC_GROUP generator
for faster point multiplication. See also
EC_POINT_add(3).
EC_KEY_print()
and
EC_KEY_print_fp()
print out the content of key to the
BIO bp or to the
FILE pointer fp, respectively.
Each line is indented by indent spaces.
RETURN VALUES
EC_KEY_new(),
EC_KEY_new_by_curve_name(), and
EC_KEY_dup() return a pointer to the newly created
EC_KEY object or NULL on
error.
EC_KEY_get_flags() returns the flags
associated with the EC_KEY object.
EC_KEY_copy() returns a pointer to the
destination key or NULL on error. In the latter
case, part of the content may already have been copied.
EC_KEY_up_ref(),
EC_KEY_set_group(),
EC_KEY_set_private_key(),
EC_KEY_set_public_key(),
EC_KEY_precompute_mult(),
EC_KEY_generate_key(),
EC_KEY_check_key(),
EC_KEY_set_public_key_affine_coordinates(),
EC_KEY_print(), and
EC_KEY_print_fp() return 1 on success or 0 on
error.
EC_KEY_get0_group() returns the
EC_GROUP associated with the
EC_KEY.
EC_KEY_get0_private_key() and
EC_KEY_get0_public_key() return the private or
public keys, respectively, associated with the
EC_KEY.
EC_KEY_get_enc_flags() returns the value
of the current encoding flags for the EC_KEY.
EC_KEY_get_conv_form() returns the
point_conversion_form for the EC_KEY.
SEE ALSO
d2i_ECPKParameters(3), EC_GFp_simple_method(3), EC_GROUP_copy(3), EC_GROUP_new(3), EC_KEY_METHOD_new(3), EC_POINT_add(3), EC_POINT_new(3), ECDH_compute_key(3), ECDSA_SIG_new(3), EVP_PKEY_set1_EC_KEY(3)
HISTORY
EC_KEY_new(),
EC_KEY_new_by_curve_name(),
EC_KEY_free(),
EC_KEY_copy(), EC_KEY_dup(),
EC_KEY_up_ref(),
EC_KEY_get0_group(),
EC_KEY_set_group(),
EC_KEY_get0_private_key(),
EC_KEY_set_private_key(),
EC_KEY_get0_public_key(),
EC_KEY_set_public_key(),
EC_KEY_get_enc_flags(),
EC_KEY_set_enc_flags(),
EC_KEY_get_conv_form(),
EC_KEY_set_conv_form(),
EC_KEY_set_asn1_flag(),
EC_KEY_precompute_mult(),
EC_KEY_generate_key(),
EC_KEY_check_key(),
EC_KEY_print(), and
EC_KEY_print_fp() first appeared in OpenSSL 0.9.8
and have been available since OpenBSD 4.5.
EC_KEY_get_flags(),
EC_KEY_set_flags(),
EC_KEY_clear_flags(), and
EC_KEY_set_public_key_affine_coordinates() first
appeared in OpenSSL 1.0.1 and have been available since
OpenBSD 5.3.