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c-kzg-4844
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Add checks that field elements are canonical

This commit is contained in:
Ramana Kumar 2022-12-02 12:30:48 +00:00
parent 0f54189400
commit cfa36097a3
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GPG Key ID: ED471C788B900433
2 changed files with 36 additions and 15 deletions
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49
src/c_kzg_4844.c
View File

@ -840,12 +840,20 @@ static void compute_powers(BLSFieldElement out[], BLSFieldElement *x, uint64_t n
}
}
void bytes_to_bls_field(BLSFieldElement *out, const uint8_t bytes[32]) {
static void hash_to_bls_field(BLSFieldElement *out, const uint8_t bytes[32]) {
blst_scalar tmp;
blst_scalar_from_lendian(&tmp, bytes);
blst_fr_from_scalar(out, &tmp);
}
C_KZG_RET bytes_to_bls_field(BLSFieldElement *out, const uint8_t bytes[32]) {
blst_scalar tmp;
blst_scalar_from_lendian(&tmp, bytes);
if (!blst_scalar_fr_check(&tmp)) return C_KZG_BADARGS;
blst_fr_from_scalar(out, &tmp);
return C_KZG_OK;
}
static void poly_lincomb(Polynomial out, const Polynomial vectors[], const fr_t scalars[], uint64_t n) {
fr_t tmp;
uint64_t i, j;
@ -923,14 +931,19 @@ static C_KZG_RET poly_to_kzg_commitment(KZGCommitment *out, const Polynomial p,
return g1_lincomb(out, s->g1_values, p, FIELD_ELEMENTS_PER_BLOB);
}
static void poly_from_blob(Polynomial p, const Blob blob) {
for (size_t i = 0; i < FIELD_ELEMENTS_PER_BLOB; i++)
bytes_to_bls_field(&p[i], &blob[i * BYTES_PER_FIELD_ELEMENT]);
static C_KZG_RET poly_from_blob(Polynomial p, const Blob blob) {
C_KZG_RET ret;
for (size_t i = 0; i < FIELD_ELEMENTS_PER_BLOB; i++) {
ret = bytes_to_bls_field(&p[i], &blob[i * BYTES_PER_FIELD_ELEMENT]);
if (ret != C_KZG_OK) return ret;
}
return C_KZG_OK;
}
C_KZG_RET blob_to_kzg_commitment(KZGCommitment *out, const Blob blob, const KZGSettings *s) {
Polynomial p;
poly_from_blob(p, blob);
C_KZG_RET ret = poly_from_blob(p, blob);
if (ret != C_KZG_OK) return ret;
return poly_to_kzg_commitment(out, p, s);
}
@ -968,8 +981,9 @@ C_KZG_RET verify_kzg_proof(bool *out,
const KZGProof *kzg_proof,
const KZGSettings *s) {
BLSFieldElement frz, fry;
bytes_to_bls_field(&frz, z);
bytes_to_bls_field(&fry, y);
C_KZG_RET ret;
ret = bytes_to_bls_field(&frz, z); if (ret != C_KZG_OK) return ret;
ret = bytes_to_bls_field(&fry, y); if (ret != C_KZG_OK) return ret;
return verify_kzg_proof_impl(out, commitment, &frz, &fry, kzg_proof, s);
}
@ -1143,14 +1157,14 @@ static C_KZG_RET compute_challenges(BLSFieldElement *out, BLSFieldElement r_powe
/* Compute r_powers */
BLSFieldElement r;
bytes_to_bls_field(&r, r_bytes);
hash_to_bls_field(&r, r_bytes);
compute_powers(r_powers, &r, n);
/* Compute eval_challenge */
uint8_t eval_challenge[32] = {0};
hash_input[32] = 0x1;
hash(eval_challenge, hash_input, 33);
bytes_to_bls_field(out, eval_challenge);
hash_to_bls_field(out, eval_challenge);
free(bytes);
return C_KZG_OK;
@ -1185,15 +1199,20 @@ C_KZG_RET compute_aggregate_kzg_proof(KZGProof *out,
Polynomial* polys = calloc(n, sizeof(Polynomial));
if (0 < n && polys == NULL) { free(commitments); return C_KZG_MALLOC; }
C_KZG_RET ret;
for (size_t i = 0; i < n; i++) {
poly_from_blob(polys[i], blobs[i]);
ret = poly_from_blob(polys[i], blobs[i]);
if (ret != C_KZG_OK) {
if (commitments != NULL) free(commitments);
if (polys != NULL) free(polys);
return ret;
}
poly_to_kzg_commitment(&commitments[i], polys[i], s);
}
Polynomial aggregated_poly;
KZGCommitment aggregated_poly_commitment;
BLSFieldElement evaluation_challenge;
C_KZG_RET ret;
ret = compute_aggregated_poly_and_commitment(aggregated_poly, &aggregated_poly_commitment, &evaluation_challenge, polys, commitments, n);
if (commitments != NULL) free(commitments);
if (polys != NULL) free(polys);
@ -1210,13 +1229,15 @@ C_KZG_RET verify_aggregate_kzg_proof(bool *out,
const KZGSettings *s) {
Polynomial* polys = calloc(n, sizeof(Polynomial));
if (polys == NULL) return C_KZG_MALLOC;
for (size_t i = 0; i < n; i++)
poly_from_blob(polys[i], blobs[i]);
C_KZG_RET ret;
for (size_t i = 0; i < n; i++) {
ret = poly_from_blob(polys[i], blobs[i]);
if (ret != C_KZG_OK) { free(polys); return ret; }
}
Polynomial aggregated_poly;
KZGCommitment aggregated_poly_commitment;
BLSFieldElement evaluation_challenge;
C_KZG_RET ret;
ret = compute_aggregated_poly_and_commitment(aggregated_poly, &aggregated_poly_commitment, &evaluation_challenge, polys, expected_kzg_commitments, n);
free(polys);
if (ret != C_KZG_OK) return ret;

2
src/c_kzg_4844.h
View File

@ -89,7 +89,7 @@ typedef struct {
C_KZG_RET bytes_to_g1(g1_t* out, const uint8_t in[48]);
void bytes_from_g1(uint8_t out[48], const g1_t *in);
void bytes_to_bls_field(BLSFieldElement *out, const uint8_t in[BYTES_PER_FIELD_ELEMENT]);
C_KZG_RET bytes_to_bls_field(BLSFieldElement *out, const uint8_t in[BYTES_PER_FIELD_ELEMENT]);
C_KZG_RET load_trusted_setup(KZGSettings *out,
const uint8_t g1_bytes[], /* n1 * 48 bytes */