Simplify secp256k1_fe_{impl_,}verify

This commit is contained in:
Pieter Wuille
2023-05-11 04:42:09 -04:00
parent 4e176ad5b9
commit 7fc642fa25
3 changed files with 24 additions and 27 deletions

View File

@@ -15,26 +15,25 @@
#ifdef VERIFY
static void secp256k1_fe_impl_verify(const secp256k1_fe *a) {
const uint32_t *d = a->n;
int m = a->normalized ? 1 : 2 * a->magnitude, r = 1;
r &= (d[0] <= 0x3FFFFFFUL * m);
r &= (d[1] <= 0x3FFFFFFUL * m);
r &= (d[2] <= 0x3FFFFFFUL * m);
r &= (d[3] <= 0x3FFFFFFUL * m);
r &= (d[4] <= 0x3FFFFFFUL * m);
r &= (d[5] <= 0x3FFFFFFUL * m);
r &= (d[6] <= 0x3FFFFFFUL * m);
r &= (d[7] <= 0x3FFFFFFUL * m);
r &= (d[8] <= 0x3FFFFFFUL * m);
r &= (d[9] <= 0x03FFFFFUL * m);
int m = a->normalized ? 1 : 2 * a->magnitude;
VERIFY_CHECK(d[0] <= 0x3FFFFFFUL * m);
VERIFY_CHECK(d[1] <= 0x3FFFFFFUL * m);
VERIFY_CHECK(d[2] <= 0x3FFFFFFUL * m);
VERIFY_CHECK(d[3] <= 0x3FFFFFFUL * m);
VERIFY_CHECK(d[4] <= 0x3FFFFFFUL * m);
VERIFY_CHECK(d[5] <= 0x3FFFFFFUL * m);
VERIFY_CHECK(d[6] <= 0x3FFFFFFUL * m);
VERIFY_CHECK(d[7] <= 0x3FFFFFFUL * m);
VERIFY_CHECK(d[8] <= 0x3FFFFFFUL * m);
VERIFY_CHECK(d[9] <= 0x03FFFFFUL * m);
if (a->normalized) {
if (r && (d[9] == 0x03FFFFFUL)) {
if (d[9] == 0x03FFFFFUL) {
uint32_t mid = d[8] & d[7] & d[6] & d[5] & d[4] & d[3] & d[2];
if (mid == 0x3FFFFFFUL) {
r &= ((d[1] + 0x40UL + ((d[0] + 0x3D1UL) >> 26)) <= 0x3FFFFFFUL);
VERIFY_CHECK((d[1] + 0x40UL + ((d[0] + 0x3D1UL) >> 26)) <= 0x3FFFFFFUL);
}
}
}
VERIFY_CHECK(r == 1);
}
#endif