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+ ge_is_on_curve()

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This commit is contained in:
Frank Denis 2017-10-22 17:44:51 +02:00
parent 88417977e3
commit 0b835b4479
2 changed files with 27 additions and 0 deletions
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25
src/libsodium/crypto_core/curve25519/ref10/curve25519_ref10.c
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@ -2091,6 +2091,31 @@ ge_mul_l(ge_p3 *r, const ge_p3 *A)
}
}
int
ge_is_on_curve(const ge_p3 *p)
{
fe x2;
fe y2;
fe z2;
fe z4;
fe t0;
fe t1;
fe_sq(x2, p->X);
fe_sq(y2, p->Y);
fe_sq(z2, p->Z);
fe_sub(t0, y2, x2);
fe_mul(t0, t0, z2);
fe_mul(t1, x2, y2);
fe_mul(t1, t1, d);
fe_sq(z4, z2);
fe_add(t1, t1, z4);
fe_sub(t0, t0, t1);
return fe_iszero(t0);
}
int
ge_is_on_main_subgroup(const ge_p3 *p)
{

2
src/libsodium/include/sodium/private/curve25519_ref10.h
View File

@ -104,6 +104,7 @@ typedef struct {
#define ge_scalarmult_base crypto_core_curve25519_ref10_ge_scalarmult_base
#define ge_double_scalarmult_vartime crypto_core_curve25519_ref10_ge_double_scalarmult_vartime
#define ge_scalarmult_vartime crypto_core_curve25519_ref10_ge_scalarmult_vartime
#define ge_is_on_curve crypto_core_curve25519_ref10_ge_is_on_curve
#define ge_is_on_main_subgroup crypto_core_curve25519_ref10_ge_is_on_main_subgroup
#define ge_has_small_order crypto_core_curve25519_ref10_ge_has_small_order
@ -119,6 +120,7 @@ extern void ge_scalarmult_base(ge_p3 *,const unsigned char *);
extern void ge_double_scalarmult_vartime(ge_p2 *,const unsigned char *,const ge_p3 *,const unsigned char *);
extern void ge_scalarmult(ge_p3 *,const unsigned char *,const ge_p3 *);
extern void ge_scalarmult_vartime(ge_p3 *,const unsigned char *,const ge_p3 *);
extern int ge_is_on_curve(const ge_p3 *p);
extern int ge_is_on_main_subgroup(const ge_p3 *p);
extern int ge_has_small_order(const unsigned char s[32], unsigned char neg);