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_get_key_method_data,
EC_KEY_insert_key_method_data,
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_get_key_method_data(EC_KEY
*key, void *(*dup_func)(void *),
void (*free_func)(void *), void
(*clear_free_func)(void *));
void
EC_KEY_insert_key_method_data(EC_KEY
*key, void *data, void
*(*dup_func)(void *), void (*free_func)(void *),
void (*clear_free_func)(void *));
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 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 please refer to
EC_GROUP_copy(3).
EC_KEY_insert_key_method_data()
and
EC_KEY_get_key_method_data()
enable the caller to associate arbitrary additional data specific to the
elliptic curve scheme being used with the EC_KEY
object. This data is treated as a "black box" by the EC library.
The data to be stored by
EC_KEY_insert_key_method_data() is provided in the
data parameter, which must have associated functions
for duplicating, freeing and "clear_freeing" the data item. If a
subsequent EC_KEY_get_key_method_data() call is
issued, the functions for duplicating, freeing and "clear_freeing"
the data item must be provided again, and they must be the same as they were
when the data item was inserted.
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 flag
EC_FLAG_COFACTOR_ECDH which is specific to ECDH and
is defined in
<openssl/ecdh.h>.
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.
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() returns the
private key 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_POINT_add(3), EC_POINT_new(3), ECDSA_SIG_new(3)