NAME¶
EC_POINT_add, EC_POINT_dbl, EC_POINT_invert, EC_POINT_is_at_infinity,
EC_POINT_is_on_curve, EC_POINT_cmp, EC_POINT_make_affine,
EC_POINTs_make_affine, EC_POINTs_mul, EC_POINT_mul, EC_GROUP_precompute_mult,
EC_GROUP_have_precompute_mult - Functions for performing mathematical
operations and tests on EC_POINT objects.
SYNOPSIS¶
#include <openssl/ec.h>
#include <openssl/bn.h>
int EC_POINT_add(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a, const EC_POINT *b, BN_CTX *ctx);
int EC_POINT_dbl(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a, BN_CTX *ctx);
int EC_POINT_invert(const EC_GROUP *group, EC_POINT *a, BN_CTX *ctx);
int EC_POINT_is_at_infinity(const EC_GROUP *group, const EC_POINT *p);
int EC_POINT_is_on_curve(const EC_GROUP *group, const EC_POINT *point, BN_CTX *ctx);
int EC_POINT_cmp(const EC_GROUP *group, const EC_POINT *a, const EC_POINT *b, BN_CTX *ctx);
int EC_POINT_make_affine(const EC_GROUP *group, EC_POINT *point, BN_CTX *ctx);
int EC_POINTs_make_affine(const EC_GROUP *group, size_t num, EC_POINT *points[], BN_CTX *ctx);
int EC_POINTs_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *n, size_t num, const EC_POINT *p[], const BIGNUM *m[], BN_CTX *ctx);
int EC_POINT_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *n, const EC_POINT *q, const BIGNUM *m, BN_CTX *ctx);
int EC_GROUP_precompute_mult(EC_GROUP *group, BN_CTX *ctx);
int EC_GROUP_have_precompute_mult(const EC_GROUP *group);
DESCRIPTION¶
EC_POINT_add adds the two points
a and
b and places the result in
r. Similarly EC_POINT_dbl doubles the point
a and places the
result in
r. In both cases it is valid for
r to be one of
a or
b.
EC_POINT_invert calculates the inverse of the supplied point
a. The
result is placed back in
a.
The function EC_POINT_is_at_infinity tests whether the supplied point is at
infinity or not.
EC_POINT_is_on_curve tests whether the supplied point is on the curve or not.
EC_POINT_cmp compares the two supplied points and tests whether or not they are
equal.
The functions EC_POINT_make_affine and EC_POINTs_make_affine force the internal
representation of the EC_POINT(s) into the affine co-ordinate system. In the
case of EC_POINTs_make_affine the value
num provides the number of
points in the array
points to be forced.
EC_POINT_mul calculates the value generator *
n +
q *
m and
stores the result in
r. The value
n may be NULL in which case
the result is just
q *
m.
EC_POINTs_mul calculates the value generator *
n +
q[0] *
m[0] + ... +
q[num-1] *
m[num-1]. As for EC_POINT_mul the
value
n may be NULL.
The function EC_GROUP_precompute_mult stores multiples of the generator for
faster point multiplication, whilst EC_GROUP_have_precompute_mult tests
whether precomputation has already been done. See
EC_GROUP_copy(3) for
information about the generator.
RETURN VALUES¶
The following functions return 1 on success or 0 on error: EC_POINT_add,
EC_POINT_dbl, EC_POINT_invert, EC_POINT_make_affine, EC_POINTs_make_affine,
EC_POINTs_make_affine, EC_POINT_mul, EC_POINTs_mul and
EC_GROUP_precompute_mult.
EC_POINT_is_at_infinity returns 1 if the point is at infinity, or 0 otherwise.
EC_POINT_is_on_curve returns 1 if the point is on the curve, 0 if not, or -1 on
error.
EC_POINT_cmp returns 1 if the points are not equal, 0 if they are, or -1 on
error.
EC_GROUP_have_precompute_mult return 1 if a precomputation has been done, or 0
if not.
SEE ALSO¶
crypto(3),
ec(3),
EC_GROUP_new(3),
EC_GROUP_copy(3),
EC_POINT_new(3),
EC_KEY_new(3),
EC_GFp_simple_method(3),
d2i_ECPKParameters(3)