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c-kzg-4844
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This commit is contained in:
Ben Edgington 2021-02-06 11:41:36 +00:00
parent 5bd2564ff8
commit a2ae798a66
2 changed files with 12 additions and 9 deletions
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4
src/kzg_proofs.c
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@ -56,7 +56,7 @@ C_KZG_RET compute_proof_multi(blst_p1 *out, const KZGSettings *ks, poly *p, cons
ASSERT(p->length >= n + 1, C_KZG_BADARGS);
// Construct x^n - x0^n
// Construct x^n - x0^n = (x - w^0)(x - w^1)...(x - w^(n-1))
init_poly(&divisor, n + 1);
// -(x0^n)
@ -99,7 +99,7 @@ bool check_proof_multi(const KZGSettings *ks, const blst_p1 *commitment, const b
fft_fr(interp.coeffs, ys, ks->fs, true, n);
// if (ret != C_KZG_OK) return ret;
// Because it is a coset, not the subgroup, we have to multiply the polynomial coefficients by x^i
// Because it is a coset, not the subgroup, we have to multiply the polynomial coefficients by x^-i
blst_fr_eucl_inverse(&inv_x, x);
inv_x_pow = inv_x;
for (uint64_t i = 1; i < n; i++) {

17
src/kzg_proofs_test.c
View File

@ -70,8 +70,9 @@ void proof_single(void) {
commit_to_poly(&commitment, &ks, &p);
TEST_CHECK(C_KZG_OK == compute_proof_single(&proof, &ks, &p, &x));
// Verify the proof for x = 25
eval_poly(&value, &p, &x);
// Verify the proof that the (unknown) polynomial has y = value at x = 25
TEST_CHECK(true == check_proof_single(&ks, &commitment, &proof, &x, &value));
free_fft_settings(&fs);
@ -93,8 +94,10 @@ void proof_multi(void) {
blst_p1 *s1 = malloc(secrets_len * sizeof(blst_p1));
blst_p2 *s2 = malloc(secrets_len * sizeof(blst_p2));
blst_fr x, tmp;
int coset_scale = 3, coset_len = (1 << coset_scale); // Where do these come from?
blst_fr ys[coset_len];
// Must have coset_scale < poly_len [TODO: why?]
int coset_scale = 3, coset_len = (1 << coset_scale);
blst_fr y[coset_len];
// Create the polynomial
init_poly(&p, poly_len);
@ -117,14 +120,14 @@ void proof_multi(void) {
fr_from_uint64(&x, 5431);
TEST_CHECK(C_KZG_OK == compute_proof_multi(&proof, &ks2, &p, &x, coset_len));
// The ys are the values of the polynomial at the points above
// y_i is the value of the polynomial at each x_i
for (int i = 0; i < coset_len; i++) {
blst_fr_mul(&tmp, &x, &ks2.fs->expanded_roots_of_unity[i]);
eval_poly(&ys[i], &p, &tmp);
eval_poly(&y[i], &p, &tmp);
}
// Verify the proof
TEST_CHECK(check_proof_multi(&ks2, &commitment, &proof, &x, ys, coset_len));
// Verify the proof that the (unknown) polynomial has value y_i at x_i
TEST_CHECK(check_proof_multi(&ks2, &commitment, &proof, &x, y, coset_len));
free_fft_settings(&fs1);
free_fft_settings(&fs2);