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

Merge #617: Pass scalar by reference in secp256k1_wnaf_const() 

8979ec0 Pass scalar by reference in secp256k1_wnaf_const() (Tim Ruffing)

Pull request description:

  After this change, no struct or union is passed by value in the
  entire codebase. This makes it easier to compile the library with
  CompCert.

Tree-SHA512: 6b23e2b39701c3eeb6ae8c8d660cabe8872ac8f13141504c1ec55c47f2009e206129b34b31796e618114b60350598187df6df4c2be0e5c1b138a6126ad6a7484
This commit is contained in:
Gregory Maxwell 2019-05-22 04:38:27 +00:00
parent 735fbde04e 8979ec0d9a
commit 975e51e0d9
No known key found for this signature in database
GPG Key ID: EAB5AF94D9E9ABE7
3 changed files with 13 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
src/bench_internal.c
View File

@ -253,7 +253,7 @@ void bench_wnaf_const(void* arg) {
bench_inv *data = (bench_inv*)arg; bench_inv *data = (bench_inv*)arg;
for (i = 0; i < 20000; i++) { for (i = 0; i < 20000; i++) {
secp256k1_wnaf_const(data->wnaf, data->scalar_x, WINDOW_A, 256); secp256k1_wnaf_const(data->wnaf, &data->scalar_x, WINDOW_A, 256);
secp256k1_scalar_add(&data->scalar_x, &data->scalar_x, &data->scalar_y); secp256k1_scalar_add(&data->scalar_x, &data->scalar_x, &data->scalar_y);
} }
} }

22
src/ecmult_const_impl.h
View File

@ -48,7 +48,7 @@
* *
* Numbers reference steps of `Algorithm SPA-resistant Width-w NAF with Odd Scalar` on pp. 335 * Numbers reference steps of `Algorithm SPA-resistant Width-w NAF with Odd Scalar` on pp. 335
*/ */
static int secp256k1_wnaf_const(int *wnaf, secp256k1_scalar s, int w, int size) { static int secp256k1_wnaf_const(int *wnaf, const secp256k1_scalar *scalar, int w, int size) {
int global_sign; int global_sign;
int skew = 0; int skew = 0;
int word = 0; int word = 0;
@ -59,7 +59,7 @@ static int secp256k1_wnaf_const(int *wnaf, secp256k1_scalar s, int w, int size)
int flip; int flip;
int bit; int bit;
secp256k1_scalar neg_s; secp256k1_scalar s;
int not_neg_one; int not_neg_one;
/* Note that we cannot handle even numbers by negating them to be odd, as is /* Note that we cannot handle even numbers by negating them to be odd, as is
* done in other implementations, since if our scalars were specified to have * done in other implementations, since if our scalars were specified to have
@ -75,12 +75,13 @@ static int secp256k1_wnaf_const(int *wnaf, secp256k1_scalar s, int w, int size)
* {1, 2} we want to add to the scalar when ensuring that it's odd. Further * {1, 2} we want to add to the scalar when ensuring that it's odd. Further
* complicating things, -1 interacts badly with `secp256k1_scalar_cadd_bit` and * complicating things, -1 interacts badly with `secp256k1_scalar_cadd_bit` and
* we need to special-case it in this logic. */ * we need to special-case it in this logic. */
flip = secp256k1_scalar_is_high(&s); flip = secp256k1_scalar_is_high(scalar);
/* We add 1 to even numbers, 2 to odd ones, noting that negation flips parity */ /* We add 1 to even numbers, 2 to odd ones, noting that negation flips parity */
bit = flip ^ !secp256k1_scalar_is_even(&s); bit = flip ^ !secp256k1_scalar_is_even(scalar);
/* We check for negative one, since adding 2 to it will cause an overflow */ /* We check for negative one, since adding 2 to it will cause an overflow */
secp256k1_scalar_negate(&neg_s, &s); secp256k1_scalar_negate(&s, scalar);
not_neg_one = !secp256k1_scalar_is_one(&neg_s); not_neg_one = !secp256k1_scalar_is_one(&s);
s = *scalar;
secp256k1_scalar_cadd_bit(&s, bit, not_neg_one); secp256k1_scalar_cadd_bit(&s, bit, not_neg_one);
/* If we had negative one, flip == 1, s.d[0] == 0, bit == 1, so caller expects /* If we had negative one, flip == 1, s.d[0] == 0, bit == 1, so caller expects
* that we added two to it and flipped it. In fact for -1 these operations are * that we added two to it and flipped it. In fact for -1 these operations are
@ -132,7 +133,6 @@ static void secp256k1_ecmult_const(secp256k1_gej *r, const secp256k1_ge *a, cons
int wnaf_1[1 + WNAF_SIZE(WINDOW_A - 1)]; int wnaf_1[1 + WNAF_SIZE(WINDOW_A - 1)];
int i; int i;
secp256k1_scalar sc = *scalar;
/* build wnaf representation for q. */ /* build wnaf representation for q. */
int rsize = size; int rsize = size;
@ -140,13 +140,13 @@ static void secp256k1_ecmult_const(secp256k1_gej *r, const secp256k1_ge *a, cons
if (size > 128) { if (size > 128) {
rsize = 128; rsize = 128;
/* split q into q_1 and q_lam (where q = q_1 + q_lam*lambda, and q_1 and q_lam are ~128 bit) */ /* split q into q_1 and q_lam (where q = q_1 + q_lam*lambda, and q_1 and q_lam are ~128 bit) */
secp256k1_scalar_split_lambda(&q_1, &q_lam, &sc); secp256k1_scalar_split_lambda(&q_1, &q_lam, scalar);
skew_1 = secp256k1_wnaf_const(wnaf_1, q_1, WINDOW_A - 1, 128); skew_1 = secp256k1_wnaf_const(wnaf_1, &q_1, WINDOW_A - 1, 128);
skew_lam = secp256k1_wnaf_const(wnaf_lam, q_lam, WINDOW_A - 1, 128); skew_lam = secp256k1_wnaf_const(wnaf_lam, &q_lam, WINDOW_A - 1, 128);
} else } else
#endif #endif
{ {
skew_1 = secp256k1_wnaf_const(wnaf_1, sc, WINDOW_A - 1, size); skew_1 = secp256k1_wnaf_const(wnaf_1, scalar, WINDOW_A - 1, size);
#ifdef USE_ENDOMORPHISM #ifdef USE_ENDOMORPHISM
skew_lam = 0; skew_lam = 0;
#endif #endif

2
src/tests.c
View File

@ -3050,7 +3050,7 @@ void test_constant_wnaf(const secp256k1_scalar *number, int w) {
} }
bits = 128; bits = 128;
#endif #endif
skew = secp256k1_wnaf_const(wnaf, num, w, bits); skew = secp256k1_wnaf_const(wnaf, &num, w, bits);
for (i = WNAF_SIZE_BITS(bits, w); i >= 0; --i) { for (i = WNAF_SIZE_BITS(bits, w); i >= 0; --i) {
secp256k1_scalar t; secp256k1_scalar t;