1EC_POINT_ADD(3)                     OpenSSL                    EC_POINT_ADD(3)
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4

NAME

6       EC_POINT_add, EC_POINT_dbl, EC_POINT_invert, EC_POINT_is_at_infinity,
7       EC_POINT_is_on_curve, EC_POINT_cmp, EC_POINT_make_affine,
8       EC_POINTs_make_affine, EC_POINTs_mul, EC_POINT_mul,
9       EC_GROUP_precompute_mult, EC_GROUP_have_precompute_mult - Functions for
10       performing mathematical operations and tests on EC_POINT objects
11

SYNOPSIS

13        #include <openssl/ec.h>
14
15        int EC_POINT_add(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a,
16                         const EC_POINT *b, BN_CTX *ctx);
17        int EC_POINT_dbl(const EC_GROUP *group, EC_POINT *r, const EC_POINT *a, BN_CTX *ctx);
18        int EC_POINT_invert(const EC_GROUP *group, EC_POINT *a, BN_CTX *ctx);
19        int EC_POINT_is_at_infinity(const EC_GROUP *group, const EC_POINT *p);
20        int EC_POINT_is_on_curve(const EC_GROUP *group, const EC_POINT *point, BN_CTX *ctx);
21        int EC_POINT_cmp(const EC_GROUP *group, const EC_POINT *a, const EC_POINT *b, BN_CTX *ctx);
22        int EC_POINT_make_affine(const EC_GROUP *group, EC_POINT *point, BN_CTX *ctx);
23        int EC_POINTs_make_affine(const EC_GROUP *group, size_t num,
24                                  EC_POINT *points[], BN_CTX *ctx);
25        int EC_POINTs_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *n, size_t num,
26                          const EC_POINT *p[], const BIGNUM *m[], BN_CTX *ctx);
27        int EC_POINT_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *n,
28                         const EC_POINT *q, const BIGNUM *m, BN_CTX *ctx);
29        int EC_GROUP_precompute_mult(EC_GROUP *group, BN_CTX *ctx);
30        int EC_GROUP_have_precompute_mult(const EC_GROUP *group);
31

DESCRIPTION

33       EC_POINT_add adds the two points a and b and places the result in r.
34       Similarly EC_POINT_dbl doubles the point a and places the result in r.
35       In both cases it is valid for r to be one of a or b.
36
37       EC_POINT_invert calculates the inverse of the supplied point a. The
38       result is placed back in a.
39
40       The function EC_POINT_is_at_infinity tests whether the supplied point
41       is at infinity or not.
42
43       EC_POINT_is_on_curve tests whether the supplied point is on the curve
44       or not.
45
46       EC_POINT_cmp compares the two supplied points and tests whether or not
47       they are equal.
48
49       The functions EC_POINT_make_affine and EC_POINTs_make_affine force the
50       internal representation of the EC_POINT(s) into the affine co-ordinate
51       system. In the case of EC_POINTs_make_affine the value num provides the
52       number of points in the array points to be forced.
53
54       EC_POINT_mul is a convenient interface to EC_POINTs_mul: it calculates
55       the value generator * n + q * m and stores the result in r.  The value
56       n may be NULL in which case the result is just q * m (variable point
57       multiplication). Alternatively, both q and m may be NULL, and n non-
58       NULL, in which case the result is just generator * n (fixed point
59       multiplication).  When performing a single fixed or variable point
60       multiplication, the underlying implementation uses a constant time
61       algorithm, when the input scalar (either n or m) is in the range [0,
62       ec_group_order).
63
64       EC_POINTs_mul calculates the value generator * n + q[0] * m[0] + ... +
65       q[num-1] * m[num-1]. As for EC_POINT_mul the value n may be NULL or num
66       may be zero.  When performing a fixed point multiplication (n is non-
67       NULL and num is 0) or a variable point multiplication (n is NULL and
68       num is 1), the underlying implementation uses a constant time
69       algorithm, when the input scalar (either n or m[0]) is in the range [0,
70       ec_group_order).
71
72       The function EC_GROUP_precompute_mult stores multiples of the generator
73       for faster point multiplication, whilst EC_GROUP_have_precompute_mult
74       tests whether precomputation has already been done. See
75       EC_GROUP_copy(3) for information about the generator.
76

RETURN VALUES

78       The following functions return 1 on success or 0 on error:
79       EC_POINT_add, EC_POINT_dbl, EC_POINT_invert, EC_POINT_make_affine,
80       EC_POINTs_make_affine, EC_POINTs_make_affine, EC_POINT_mul,
81       EC_POINTs_mul and EC_GROUP_precompute_mult.
82
83       EC_POINT_is_at_infinity returns 1 if the point is at infinity, or 0
84       otherwise.
85
86       EC_POINT_is_on_curve returns 1 if the point is on the curve, 0 if not,
87       or -1 on error.
88
89       EC_POINT_cmp returns 1 if the points are not equal, 0 if they are, or
90       -1 on error.
91
92       EC_GROUP_have_precompute_mult return 1 if a precomputation has been
93       done, or 0 if not.
94

SEE ALSO

96       crypto(7), EC_GROUP_new(3), EC_GROUP_copy(3), EC_POINT_new(3),
97       EC_KEY_new(3), EC_GFp_simple_method(3), d2i_ECPKParameters(3)
98

100       Copyright 2013-2018 The OpenSSL Project Authors. All Rights Reserved.
101
102       Licensed under the OpenSSL license (the "License").  You may not use
103       this file except in compliance with the License.  You can obtain a copy
104       in the file LICENSE in the source distribution or at
105       <https://www.openssl.org/source/license.html>.
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1091.1.1d                            2019-10-03                   EC_POINT_ADD(3)
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