status-im
/
secp256k1
mirror of https://github.com/status-im/secp256k1.git
2
0
Fork 0
Code Issues Projects Releases Wiki Activity

Switch ecmult_gen to use storage types

This commit is contained in:
Pieter Wuille 2015-01-25 00:46:31 -04:00
parent 41f8455434
commit 55422b6aaf
3 changed files with 14 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
src/ecmult_gen_impl.h
View File

@ -24,7 +24,7 @@ typedef struct {
* None of the resulting prec group elements have a known scalar, and neither do any of
* the intermediate sums while computing a*G.
*/
secp256k1_fe_t prec[64][16][2]; /* prec[j][i] = (16^j * i * G + U_i).{x,y} */
secp256k1_ge_storage_t prec[64][16]; /* prec[j][i] = 16^j * i * G + U_i */
} secp256k1_ecmult_gen_consts_t;
static const secp256k1_ecmult_gen_consts_t *secp256k1_ecmult_gen_consts = NULL;
@ -80,9 +80,7 @@ static void secp256k1_ecmult_gen_start(void) {
}
for (int j=0; j<64; j++) {
for (int i=0; i<16; i++) {
VERIFY_CHECK(!secp256k1_ge_is_infinity(&prec[j*16 + i]));
ret->prec[j][i][0] = prec[j*16 + i].x;
ret->prec[j][i][1] = prec[j*16 + i].y;
secp256k1_ge_to_storage(&ret->prec[j][i], &prec[j*16 + i]);
}
}
@ -101,16 +99,17 @@ static void secp256k1_ecmult_gen_stop(void) {
static void secp256k1_ecmult_gen(secp256k1_gej_t *r, const secp256k1_scalar_t *gn) {
const secp256k1_ecmult_gen_consts_t *c = secp256k1_ecmult_gen_consts;
secp256k1_gej_set_infinity(r);
secp256k1_ge_t add;
secp256k1_ge_storage_t adds;
secp256k1_gej_set_infinity(r);
add.infinity = 0;
int bits;
for (int j=0; j<64; j++) {
bits = secp256k1_scalar_get_bits(gn, j * 4, 4);
for (int i=0; i<16; i++) {
secp256k1_fe_cmov(&add.x, &c->prec[j][i][0], i == bits);
secp256k1_fe_cmov(&add.y, &c->prec[j][i][1], i == bits);
secp256k1_ge_storage_cmov(&adds, &c->prec[j][i], i == bits);
}
secp256k1_ge_from_storage(&add, &adds);
secp256k1_gej_add_ge(r, r, &add);
}
bits = 0;

3
src/group.h
View File

@ -110,4 +110,7 @@ static void secp256k1_ge_to_storage(secp256k1_ge_storage_t *r, const secp256k1_g
/** Convert a group element back from the storage type. */
static void secp256k1_ge_from_storage(secp256k1_ge_t *r, const secp256k1_ge_storage_t*);
/** If flag is true, set *r equal to *a; otherwise leave it. Constant-time. */
static void secp256k1_ge_storage_cmov(secp256k1_ge_storage_t *r, const secp256k1_ge_storage_t *a, int flag);
#endif

5
src/group_impl.h
View File

@ -409,6 +409,11 @@ static void secp256k1_ge_from_storage(secp256k1_ge_t *r, const secp256k1_ge_stor
r->infinity = 0;
}
static SECP256K1_INLINE void secp256k1_ge_storage_cmov(secp256k1_ge_storage_t *r, const secp256k1_ge_storage_t *a, int flag) {
secp256k1_fe_storage_cmov(&r->x, &a->x, flag);
secp256k1_fe_storage_cmov(&r->y, &a->y, flag);
}
#ifdef USE_ENDOMORPHISM
static void secp256k1_gej_mul_lambda(secp256k1_gej_t *r, const secp256k1_gej_t *a) {
static const secp256k1_fe_t beta = SECP256K1_FE_CONST(