void test_sqrt(const secp256k1_fe_t *a, const secp256k1_fe_t *k) { secp256k1_fe_t r1, r2; int v = secp256k1_fe_sqrt(&r1, a); CHECK((v == 0) == (k == NULL)); if (k != NULL) { /* Check that the returned root is +/- the given known answer */ secp256k1_fe_negate(&r2, &r1, 1); secp256k1_fe_add(&r1, k); secp256k1_fe_add(&r2, k); secp256k1_fe_normalize(&r1); secp256k1_fe_normalize(&r2); CHECK(secp256k1_fe_is_zero(&r1) || secp256k1_fe_is_zero(&r2)); } }
void random_fe_non_zero(secp256k1_fe_t *nz) { int tries = 10; while (--tries >= 0) { random_fe(nz); secp256k1_fe_normalize(nz); if (!secp256k1_fe_is_zero(nz)) break; } /* Infinitesimal probability of spurious failure here */ CHECK(tries >= 0); }
void random_group_element_jacobian_test(secp256k1_gej_t *gej, const secp256k1_ge_t *ge) { do { random_field_element_test(&gej->z); if (!secp256k1_fe_is_zero(&gej->z)) { break; } } while(1); secp256k1_fe_t z2; secp256k1_fe_sqr(&z2, &gej->z); secp256k1_fe_t z3; secp256k1_fe_mul(&z3, &z2, &gej->z); secp256k1_fe_mul(&gej->x, &ge->x, &z2); secp256k1_fe_mul(&gej->y, &ge->y, &z3); gej->infinity = ge->infinity; }
static int secp256k1_pubkey_load(const secp256k1_context* ctx, secp256k1_ge* ge, const secp256k1_pubkey* pubkey) { if (sizeof(secp256k1_ge_storage) == 64) { /* When the secp256k1_ge_storage type is exactly 64 byte, use its * representation inside secp256k1_pubkey, as conversion is very fast. * Note that secp256k1_pubkey_save must use the same representation. */ secp256k1_ge_storage s; memcpy(&s, &pubkey->data[0], sizeof(s)); secp256k1_ge_from_storage(ge, &s); } else { /* Otherwise, fall back to 32-byte big endian for X and Y. */ secp256k1_fe x, y; secp256k1_fe_set_b32(&x, pubkey->data); secp256k1_fe_set_b32(&y, pubkey->data + 32); secp256k1_ge_set_xy(ge, &x, &y); } ARG_CHECK(!secp256k1_fe_is_zero(&ge->x)); return 1; }