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secp256k1
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Fix VERIFY calculations in _fe_cmov methods

This commit is contained in:
Peter Dettman 2015-07-04 13:50:15 +09:30
parent 17f7148606
commit a0601cd79c
3 changed files with 22 additions and 8 deletions
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6
src/field_10x26_impl.h
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@ -1083,8 +1083,10 @@ static SECP256K1_INLINE void secp256k1_fe_cmov(secp256k1_fe_t *r, const secp256k
r->n[8] = (r->n[8] & mask0) | (a->n[8] & mask1); r->n[8] = (r->n[8] & mask0) | (a->n[8] & mask1);
r->n[9] = (r->n[9] & mask0) | (a->n[9] & mask1); r->n[9] = (r->n[9] & mask0) | (a->n[9] & mask1);
#ifdef VERIFY #ifdef VERIFY
r->magnitude = (r->magnitude & mask0) | (a->magnitude & mask1); if (a->magnitude > r->magnitude) {
r->normalized = (r->normalized & mask0) | (a->normalized & mask1); r->magnitude = a->magnitude;
}
r->normalized &= a->normalized;
#endif #endif
} }

6
src/field_5x52_impl.h
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@ -414,8 +414,10 @@ static SECP256K1_INLINE void secp256k1_fe_cmov(secp256k1_fe_t *r, const secp256k
r->n[3] = (r->n[3] & mask0) | (a->n[3] & mask1); r->n[3] = (r->n[3] & mask0) | (a->n[3] & mask1);
r->n[4] = (r->n[4] & mask0) | (a->n[4] & mask1); r->n[4] = (r->n[4] & mask0) | (a->n[4] & mask1);
#ifdef VERIFY #ifdef VERIFY
r->magnitude = (r->magnitude & mask0) | (a->magnitude & mask1); if (a->magnitude > r->magnitude) {
r->normalized = (r->normalized & mask0) | (a->normalized & mask1); r->magnitude = a->magnitude;
}
r->normalized &= a->normalized;
#endif #endif
} }

18
src/tests.c
View File

@ -737,6 +737,15 @@ void run_field_convert(void) {
CHECK(memcmp(&fes2, &fes, sizeof(fes)) == 0); CHECK(memcmp(&fes2, &fes, sizeof(fes)) == 0);
} }
int fe_memcmp(const secp256k1_fe_t *a, const secp256k1_fe_t *b) {
secp256k1_fe_t t = *b;
#ifdef VERIFY
t.magnitude = a->magnitude;
t.normalized = a->normalized;
#endif
return memcmp(a, &t, sizeof(secp256k1_fe_t));
}
void run_field_misc(void) { void run_field_misc(void) {
secp256k1_fe_t x; secp256k1_fe_t x;
secp256k1_fe_t y; secp256k1_fe_t y;
@ -757,12 +766,13 @@ void run_field_misc(void) {
q = x; q = x;
secp256k1_fe_cmov(&x, &z, 0); secp256k1_fe_cmov(&x, &z, 0);
secp256k1_fe_cmov(&x, &x, 1); secp256k1_fe_cmov(&x, &x, 1);
CHECK(memcmp(&x, &z, sizeof(x)) != 0); CHECK(fe_memcmp(&x, &z) != 0);
CHECK(memcmp(&x, &q, sizeof(x)) == 0); CHECK(fe_memcmp(&x, &q) == 0);
secp256k1_fe_cmov(&q, &z, 1); secp256k1_fe_cmov(&q, &z, 1);
CHECK(memcmp(&q, &z, sizeof(q)) == 0); CHECK(fe_memcmp(&q, &z) == 0);
/* Test storage conversion and conditional moves. */ /* Test storage conversion and conditional moves. */
secp256k1_fe_normalize(&z); secp256k1_fe_normalize_var(&x);
secp256k1_fe_normalize_var(&z);
CHECK(!secp256k1_fe_equal_var(&x, &z)); CHECK(!secp256k1_fe_equal_var(&x, &z));
secp256k1_fe_to_storage(&xs, &x); secp256k1_fe_to_storage(&xs, &x);
secp256k1_fe_to_storage(&ys, &y); secp256k1_fe_to_storage(&ys, &y);