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EC_POINT_add(3)                     OpenSSL                    EC_POINT_add(3)



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

LIBRARY
       libcrypto, -lcrypto

SYNOPSIS
        #include <openssl/ec.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 is a convenient interface to EC_POINTs_mul: it 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 (variable point
       multiplication). Alternatively, both q and m may be NULL, and n non-
       NULL, in which case the result is just generator * n (fixed point
       multiplication).  When performing a single fixed or variable point
       multiplication, the underlying implementation uses a constant time
       algorithm, when the input scalar (either n or m) is in the range [0,
       ec_group_order).

       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 or num
       may be zero.  When performing a fixed point multiplication (n is non-
       NULL and num is 0) or a variable point multiplication (n is NULL and
       num is 1), the underlying implementation uses a constant time
       algorithm, when the input scalar (either n or m[0]) is in the range [0,
       ec_group_order).

       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(7), EC_GROUP_new(3), EC_GROUP_copy(3), EC_POINT_new(3),
       EC_KEY_new(3), EC_GFp_simple_method(3), d2i_ECPKParameters(3)

COPYRIGHT
       Copyright 2013-2018 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the OpenSSL license (the "License").  You may not use
       this file except in compliance with the License.  You can obtain a copy
       in the file LICENSE in the source distribution or at
       <https://www.openssl.org/source/license.html>.



1.1.1                             2018-09-17                   EC_POINT_add(3)