openssl/doc/crypto/EC_POINT_add.pod
Matt Caswell aafbe1ccd2 Document updates from wiki.
PR#3071

The primary changes made are:
- Updates to the "NAME" section of many pages to correctly reflect the
functions defined on those pages. This section is automatically parsed
by the util/extract-names.pl script, so if it is not correct then
running "man" will not correctly locate the right manual pages.
- Updates to take account of where functions are now deprecated
- Full documentation of the ec sub-library
- A number of other typo corrections and other minor tweaks
2013-06-12 23:42:08 +01:00

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=pod
=head1 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 B<EC_POINT> objects.
=head1 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);
=head1 DESCRIPTION
EC_POINT_add adds the two points B<a> and B<b> and places the result in B<r>. Similarly EC_POINT_dbl doubles the point B<a> and places the
result in B<r>. In both cases it is valid for B<r> to be one of B<a> or B<b>.
EC_POINT_invert calculates the inverse of the supplied point B<a>. The result is placed back in B<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 B<num> provides the number of points in the array B<points> to be
forced.
EC_POINT_mul calculates the value generator * B<n> + B<q> * B<m> and stores the result in B<r>. The value B<n> may be NULL in which case the result is just B<q> * B<m>.
EC_POINTs_mul calculates the value generator * B<n> + B<q[0]> * B<m[0]> + ... + B<q[num-1]> * B<m[num-1]>. As for EC_POINT_mul the value
B<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 L<EC_GROUP_copy(3)|EC_GROUP_copy(3)> for information
about the generator.
=head1 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.
=head1 SEE ALSO
L<crypto(3)|crypto(3)>, L<ec(3)|ec(3)>, L<EC_GROUP_new(3)|EC_GROUP_new(3)>, L<EC_GROUP_copy(3)|EC_GROUP_copy(3)>,
L<EC_POINT_new(3)|EC_POINT_new(3)>, L<EC_KEY_new(3)|EC_KEY_new(3)>,
L<EC_GFp_simple_method(3)|EC_GFp_simple_method(3)>, L<d2i_ECPKParameters(3)|d2i_ECPKParameters(3)>
=cut