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EC_POINT_new(3) OpenSSL EC_POINT_new(3)
NAME
EC_POINT_new, EC_POINT_free, EC_POINT_clear_free, EC_POINT_copy, EC_POINT_dup,
EC_POINT_method_of, EC_POINT_set_to_infinity, EC_POINT_set_Jprojective_coordinates,
EC_POINT_get_Jprojective_coordinates_GFp, EC_POINT_set_affine_coordinates_GFp,
EC_POINT_get_affine_coordinates_GFp, EC_POINT_set_compressed_coordinates_GFp,
EC_POINT_set_affine_coordinates_GF2m, EC_POINT_get_affine_coordinates_GF2m,
EC_POINT_set_compressed_coordinates_GF2m, EC_POINT_point2oct, EC_POINT_oct2point,
EC_POINT_point2bn, EC_POINT_bn2point, EC_POINT_point2hex, EC_POINT_hex2point - Functions
for creating, destroying and manipulating EC_POINT objects.
SYNOPSIS
#include <openssl/ec.h>
#include <openssl/bn.h>
EC_POINT *EC_POINT_new(const EC_GROUP *group);
void EC_POINT_free(EC_POINT *point);
void EC_POINT_clear_free(EC_POINT *point);
int EC_POINT_copy(EC_POINT *dst, const EC_POINT *src);
EC_POINT *EC_POINT_dup(const EC_POINT *src, const EC_GROUP *group);
const EC_METHOD *EC_POINT_method_of(const EC_POINT *point);
int EC_POINT_set_to_infinity(const EC_GROUP *group, EC_POINT *point);
int EC_POINT_set_Jprojective_coordinates_GFp(const EC_GROUP *group, EC_POINT *p,
const BIGNUM *x, const BIGNUM *y, const BIGNUM *z, BN_CTX *ctx);
int EC_POINT_get_Jprojective_coordinates_GFp(const EC_GROUP *group,
const EC_POINT *p, BIGNUM *x, BIGNUM *y, BIGNUM *z, BN_CTX *ctx);
int EC_POINT_set_affine_coordinates_GFp(const EC_GROUP *group, EC_POINT *p,
const BIGNUM *x, const BIGNUM *y, BN_CTX *ctx);
int EC_POINT_get_affine_coordinates_GFp(const EC_GROUP *group,
const EC_POINT *p, BIGNUM *x, BIGNUM *y, BN_CTX *ctx);
int EC_POINT_set_compressed_coordinates_GFp(const EC_GROUP *group, EC_POINT *p,
const BIGNUM *x, int y_bit, BN_CTX *ctx);
int EC_POINT_set_affine_coordinates_GF2m(const EC_GROUP *group, EC_POINT *p,
const BIGNUM *x, const BIGNUM *y, BN_CTX *ctx);
int EC_POINT_get_affine_coordinates_GF2m(const EC_GROUP *group,
const EC_POINT *p, BIGNUM *x, BIGNUM *y, BN_CTX *ctx);
int EC_POINT_set_compressed_coordinates_GF2m(const EC_GROUP *group, EC_POINT *p,
const BIGNUM *x, int y_bit, BN_CTX *ctx);
size_t EC_POINT_point2oct(const EC_GROUP *group, const EC_POINT *p,
point_conversion_form_t form,
unsigned char *buf, size_t len, BN_CTX *ctx);
int EC_POINT_oct2point(const EC_GROUP *group, EC_POINT *p,
const unsigned char *buf, size_t len, BN_CTX *ctx);
BIGNUM *EC_POINT_point2bn(const EC_GROUP *, const EC_POINT *,
point_conversion_form_t form, BIGNUM *, BN_CTX *);
EC_POINT *EC_POINT_bn2point(const EC_GROUP *, const BIGNUM *,
EC_POINT *, BN_CTX *);
char *EC_POINT_point2hex(const EC_GROUP *, const EC_POINT *,
point_conversion_form_t form, BN_CTX *);
EC_POINT *EC_POINT_hex2point(const EC_GROUP *, const char *,
EC_POINT *, BN_CTX *);
DESCRIPTION
An EC_POINT represents a point on a curve. A new point is constructed by calling the
function EC_POINT_new and providing the group object that the point relates to.
EC_POINT_free frees the memory associated with the EC_POINT.
EC_POINT_clear_free destroys any sensitive data held within the EC_POINT and then frees
its memory.
EC_POINT_copy copies the point src into dst. Both src and dst must use the same EC_METHOD.
EC_POINT_dup creates a new EC_POINT object and copies the content from src to the newly
created EC_POINT object.
EC_POINT_method_of obtains the EC_METHOD associated with point.
A valid point on a curve is the special point at infinity. A point is set to be at
infinity by calling EC_POINT_set_to_infinity.
The affine co-ordinates for a point describe a point in terms of its x and y position. The
functions EC_POINT_set_affine_coordinates_GFp and EC_POINT_set_affine_coordinates_GF2m set
the x and y co-ordinates for the point p defined over the curve given in group.
As well as the affine co-ordinates, a point can alternatively be described in terms of its
Jacobian projective co-ordinates (for Fp curves only). Jacobian projective co-ordinates
are expressed as three values x, y and z. Working in this co-ordinate system provides more
efficient point multiplication operations. A mapping exists between Jacobian projective
co-ordinates and affine co-ordinates. A Jacobian projective co-ordinate (x, y, z) can be
written as an affine co-ordinate as (x/(z^2), y/(z^3)). Conversion to Jacobian projective
to affine co-ordinates is simple. The co-ordinate (x, y) is mapped to (x, y, 1). To set or
get the projective co-ordinates use EC_POINT_set_Jprojective_coordinates_GFp and
EC_POINT_get_Jprojective_coordinates_GFp respectively.
Points can also be described in terms of their compressed co-ordinates. For a point (x,
y), for any given value for x such that the point is on the curve there will only ever be
two possible values for y. Therefore a point can be set using the
EC_POINT_set_compressed_coordinates_GFp and EC_POINT_set_compressed_coordinates_GF2m
functions where x is the x co-ordinate and y_bit is a value 0 or 1 to identify which of
the two possible values for y should be used.
In addition EC_POINTs can be converted to and from various external representations.
Supported representations are octet strings, BIGNUMs and hexadecimal. Octet strings are
stored in a buffer along with an associated buffer length. A point held in a BIGNUM is
calculated by converting the point to an octet string and then converting that octet
string into a BIGNUM integer. Points in hexadecimal format are stored in a NULL
terminated character string where each character is one of the printable values 0-9 or A-F
(or a-f).
The functions EC_POINT_point2oct, EC_POINT_oct2point, EC_POINT_point2bn,
EC_POINT_bn2point, EC_POINT_point2hex and EC_POINT_hex2point convert from and to EC_POINTs
for the formats: octet string, BIGNUM and hexadecimal respectively.
The function EC_POINT_point2oct must be supplied with a buffer long enough to store the
octet string. The return value provides the number of octets stored. Calling the function
with a NULL buffer will not perform the conversion but will still return the required
buffer length.
The function EC_POINT_point2hex will allocate sufficient memory to store the hexadecimal
string. It is the caller's responsibility to free this memory with a subsequent call to
OPENSSL_free().
RETURN VALUES
EC_POINT_new and EC_POINT_dup return the newly allocated EC_POINT or NULL on error.
The following functions return 1 on success or 0 on error: EC_POINT_copy,
EC_POINT_set_to_infinity, EC_POINT_set_Jprojective_coordinates_GFp,
EC_POINT_get_Jprojective_coordinates_GFp, EC_POINT_set_affine_coordinates_GFp,
EC_POINT_get_affine_coordinates_GFp, EC_POINT_set_compressed_coordinates_GFp,
EC_POINT_set_affine_coordinates_GF2m, EC_POINT_get_affine_coordinates_GF2m,
EC_POINT_set_compressed_coordinates_GF2m and EC_POINT_oct2point.
EC_POINT_method_of returns the EC_METHOD associated with the supplied EC_POINT.
EC_POINT_point2oct returns the length of the required buffer, or 0 on error.
EC_POINT_point2bn returns the pointer to the BIGNUM supplied, or NULL on error.
EC_POINT_bn2point returns the pointer to the EC_POINT supplied, or NULL on error.
EC_POINT_point2hex returns a pointer to the hex string, or NULL on error.
EC_POINT_hex2point returns the pointer to the EC_POINT supplied, or NULL on error.
SEE ALSO
crypto(3), ec(3), EC_GROUP_new(3), EC_GROUP_copy(3), EC_POINT_add(3), EC_KEY_new(3),
EC_GFp_simple_method(3), d2i_ECPKParameters(3)
1.0.2k 2017-01-26 EC_POINT_new(3)
Generated by $Id: phpMan.php,v 4.55 2007/09/05 04:42:51 chedong Exp $ Author: Che Dong
On Apache/2.4.6 (CentOS)
Under GNU General Public License
2025-06-23 22:12 @127.0.0.1 CrawledBy Wget/1.21.2