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#include "fe25519.h"
#include "sc25519.h"
#include "ge25519.h"
/* Multiples of the base point in Niels' representation */
static const ge25519_niels ge25519_base_multiples_niels[] = {
#ifdef SMALLTABLES
#include "ge25519_base_niels_smalltables.data"
#else
#include "ge25519_base_niels.data"
#endif
};
/* d */
static const fe25519 ecd = {{0x75EB4DCA135978A3, 0x00700A4D4141D8AB, 0x8CC740797779E898, 0x52036CEE2B6FFE73}};
void ge25519_scalarmult_base(ge25519_p3 *r, const sc25519 *s)
{
signed char b[64];
int i;
ge25519_niels t;
fe25519 d;
sc25519_window4(b,s);
#ifdef SMALLTABLES
ge25519_p1p1 tp1p1;
choose_t((ge25519_niels *)r, 0, (signed long long) b[1], ge25519_base_multiples_niels);
fe25519_sub(&d, &r->y, &r->x);
fe25519_add(&r->y, &r->y, &r->x);
r->x = d;
r->t = r->z;
fe25519_setint(&r->z,2);
for(i=3;i<64;i+=2)
{
choose_t(&t, (unsigned long long) i/2, (signed long long) b[i], ge25519_base_multiples_niels);
ge25519_nielsadd2(r, &t);
}
ge25519_dbl_p1p1(&tp1p1,(ge25519_p2 *)r);
ge25519_p1p1_to_p2((ge25519_p2 *)r, &tp1p1);
ge25519_dbl_p1p1(&tp1p1,(ge25519_p2 *)r);
ge25519_p1p1_to_p2((ge25519_p2 *)r, &tp1p1);
ge25519_dbl_p1p1(&tp1p1,(ge25519_p2 *)r);
ge25519_p1p1_to_p2((ge25519_p2 *)r, &tp1p1);
ge25519_dbl_p1p1(&tp1p1,(ge25519_p2 *)r);
ge25519_p1p1_to_p3(r, &tp1p1);
choose_t(&t, (unsigned long long) 0, (signed long long) b[0], ge25519_base_multiples_niels);
fe25519_mul(&t.t2d, &t.t2d, &ecd);
ge25519_nielsadd2(r, &t);
for(i=2;i<64;i+=2)
{
choose_t(&t, (unsigned long long) i/2, (signed long long) b[i], ge25519_base_multiples_niels);
ge25519_nielsadd2(r, &t);
}
#else
choose_t((ge25519_niels *)r, 0, (signed long long) b[0], ge25519_base_multiples_niels);
fe25519_sub(&d, &r->y, &r->x);
fe25519_add(&r->y, &r->y, &r->x);
r->x = d;
r->t = r->z;
fe25519_setint(&r->z,2);
for(i=1;i<64;i++)
{
choose_t(&t, (unsigned long long) i, (signed long long) b[i], ge25519_base_multiples_niels);
ge25519_nielsadd2(r, &t);
}
#endif
}
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