computeAggregateKzgProof + verifyAggregateKzgProof test passes

bindings/node.js/kzg.cxx

@@ -163,7 +163,7 @@ Napi::Value ComputeAggregateKzgProof(const Napi::CallbackInfo& info) {
   return napi_typed_array_from_bytes(proofBytes, BYTES_PER_PROOF, env);
 }
 
-// verifyAggregateKzgProof: (blobs: Blob[], expectedKzgCommitments: KZGCommitment[], kzgAggregatedProof: KZGProof) => boolean;
+// verifyAggregateKzgProof: (blobs: Blob[], expectedKzgCommitments: KZGCommitment[], kzgAggregatedProof: KZGProof, setupHandle: SetupHandle) => boolean;
 Napi::Value VerifyAggregateKzgProof(const Napi::CallbackInfo& info) {
   auto env = info.Env();
 
@@ -189,23 +189,29 @@ Napi::Value VerifyAggregateKzgProof(const Napi::CallbackInfo& info) {
   C_KZG_RET ret;
 
   for (uint32_t blobIndex = 0; blobIndex < numberOfBlobs; blobIndex++) {
+    // Extract blob bytes from parameter
     Napi::Value blob = blobs_param[blobIndex];
     auto blobBytes = blob.As<Napi::Uint8Array>().Data();
 
-    Napi::Value commitment = comittments_param[blobIndex];
+    // Populate the polynomial with a BLS field for each field element in the blob
-    auto commitmentBytes = commitment.As<Napi::Uint8Array>().Data();
-
     for (uint32_t fieldIndex = 0; fieldIndex < FIELD_ELEMENTS_PER_BLOB; fieldIndex++) {
        bytes_to_bls_field(&polynomial[blobIndex][fieldIndex], &blobBytes[fieldIndex * BYTES_PER_FIELD]);
     }
 
-    ret = bytes_to_g1(&commitments[blobIndex], &commitmentBytes[blobIndex * BYTES_PER_COMMITMENT]);
+    // Extract a G1 point for each commitment
+    Napi::Value commitment = comittments_param[blobIndex];
+    auto commitmentBytes = commitment.As<Napi::Uint8Array>().Data();
+
+    ret = bytes_to_g1(&commitments[blobIndex], commitmentBytes);
     if (ret != C_KZG_OK) {
+      std::ostringstream ss;
+      std::copy(commitmentBytes, commitmentBytes + BYTES_PER_COMMITMENT, std::ostream_iterator<int>(ss, ","));
+
+      Napi::TypeError::New(env, "Error parsing commitment. Error code was: " + std::to_string(ret) + ". Commitment bytes: " + ss.str()).ThrowAsJavaScriptException();
+
       free(commitments);
       free(polynomial);
 
-      Napi::TypeError::New(env, "Error parsing blobs and commitments")
-        .ThrowAsJavaScriptException();
       return env.Null();
     }
   }
@@ -260,15 +266,15 @@ Napi::Value VerifyKzgProof(const Napi::CallbackInfo& info) {
         .ThrowAsJavaScriptException();
     return env.Undefined();
   }
-  auto c = c_param.As<Napi::Uint8Array>().Data();
+  auto polynomialKzg = c_param.As<Napi::Uint8Array>().Data();
 
-  auto x_param = info[0].As<Napi::TypedArray>();
+  auto z_param = info[0].As<Napi::TypedArray>();
-  if (x_param.TypedArrayType() != napi_uint8_array) {
+  if (z_param.TypedArrayType() != napi_uint8_array) {
     Napi::Error::New(env, "Expected an Uint8Array")
         .ThrowAsJavaScriptException();
     return env.Undefined();
   }
-  auto x = x_param.As<Napi::Uint8Array>().Data();
+  auto z = z_param.As<Napi::Uint8Array>().Data();
 
   auto y_param = info[0].As<Napi::TypedArray>();
   if (y_param.TypedArrayType() != napi_uint8_array) {
@@ -278,37 +284,36 @@ Napi::Value VerifyKzgProof(const Napi::CallbackInfo& info) {
   }
   auto y = y_param.As<Napi::Uint8Array>().Data();
 
-  auto p_param = info[0].As<Napi::TypedArray>();
+  auto proof_param = info[0].As<Napi::TypedArray>();
-  if (p_param.TypedArrayType() != napi_uint8_array) {
+  if (proof_param.TypedArrayType() != napi_uint8_array) {
     Napi::Error::New(info.Env(), "Expected an Uint8Array")
         .ThrowAsJavaScriptException();
     return info.Env().Undefined();
   }
-  auto p = p_param.As<Napi::Uint8Array>().Data();
+  auto kzgProof = proof_param.As<Napi::Uint8Array>().Data();
 
   auto kzgSettings = info[4].As<Napi::External<KZGSettings>>().Data();
 
-  KZGCommitment commitment;
-  KZGProof proof;
   BLSFieldElement fx, fy;
-  bool out;
+  bytes_to_bls_field(&fx, z);
-
-  bytes_to_bls_field(&fx, x);
   bytes_to_bls_field(&fy, y);
 
-  auto ret = bytes_to_g1(&commitment, c);
+  KZGCommitment commitment;
+  auto ret = bytes_to_g1(&commitment, polynomialKzg);
   if (ret != C_KZG_OK) {
     std::ostringstream ss;
-    std::copy(c, c+sizeof(c), std::ostream_iterator<int>(ss, ","));
+    std::copy(polynomialKzg, polynomialKzg + BYTES_PER_COMMITMENT, std::ostream_iterator<int>(ss, ","));
     Napi::TypeError::New(env, "Failed to parse argument commitment: "  + ss.str() + " Return code was: " + std::to_string(ret)).ThrowAsJavaScriptException();
     return env.Null();
   };
 
-  if (bytes_to_g1(&proof, p) != C_KZG_OK) {
+  KZGProof proof;
-    Napi::TypeError::New(env, "Wrong arguments").ThrowAsJavaScriptException();
+  if (bytes_to_g1(&proof, kzgProof) != C_KZG_OK) {
+    Napi::TypeError::New(env, "Invalid kzgProof").ThrowAsJavaScriptException();
     return env.Null();
   }
 
+  bool out;
   if (verify_kzg_proof(&out, &commitment, &fx, &fy, &proof, kzgSettings) != C_KZG_OK) {
     return Napi::Boolean::New(env, false);
   }
@@ -317,12 +322,18 @@ Napi::Value VerifyKzgProof(const Napi::CallbackInfo& info) {
 }
 
 Napi::Object Init(Napi::Env env, Napi::Object exports) {
+  // Functions
   exports["loadTrustedSetup"] = Napi::Function::New(env, LoadTrustedSetup);
   exports["freeTrustedSetup"] = Napi::Function::New(env, FreeTrustedSetup);
   exports["verifyKzgProof"] = Napi::Function::New(env, VerifyKzgProof);
   exports["blobToKzgCommitment"] = Napi::Function::New(env, BlobToKzgCommitment);
   exports["computeAggregateKzgProof"] = Napi::Function::New(env, ComputeAggregateKzgProof);
   exports["verifyAggregateKzgProof"] = Napi::Function::New(env, VerifyAggregateKzgProof);
+
+  // Constants
+  exports["FIELD_ELEMENTS_PER_BLOB"] = Napi::Number::New(env, FIELD_ELEMENTS_PER_BLOB);
+  exports["BYTES_PER_FIELD"] = Napi::Number::New(env, BYTES_PER_FIELD);
+
   return exports;
 }
 

bindings/node.js/kzg.ts

@@ -1,17 +1,23 @@
 // @ts-expect-error
 import bindings from "bindings";
 
-export const BLOB_SIZE = 4096;
+/**
-export const NUMBER_OF_FIELDS = 32;
+ * The public interface of this module exposes the functions as specified by
+ * https://github.com/ethereum/consensus-specs/blob/dev/specs/eip4844/polynomial-commitments.md#kzg
+ */
 
-export type SetupHandle = Object;
+export type BLSFieldElement = Uint8Array; // 32 bytes
+export type KZGProof = Uint8Array; // 48 bytes
+export type KZGCommitment = Uint8Array; // 48 bytes
+export type Blob = Uint8Array; // 4096 * 32 bytes
 
-export type BLSFieldElement = Uint8Array;
+type SetupHandle = Object;
-export type KZGProof = Uint8Array;
-export type KZGCommitment = Uint8Array;
-export type Blob = Uint8Array;
 
+// The C++ native addon interface
 type KZG = {
+  FIELD_ELEMENTS_PER_BLOB: number;
+  BYTES_PER_FIELD: number;
+
   loadTrustedSetup: (filePath: string) => SetupHandle;
 
   freeTrustedSetup: (setupHandle: SetupHandle) => void;
@@ -41,6 +47,9 @@ type KZG = {
 
 const kzg: KZG = bindings("kzg.node");
 
+export const FIELD_ELEMENTS_PER_BLOB = kzg.FIELD_ELEMENTS_PER_BLOB;
+export const BYTES_PER_FIELD = kzg.BYTES_PER_FIELD;
+
 // Stored as internal state
 let setupHandle: SetupHandle | undefined;
 
@@ -83,7 +92,7 @@ export function verifyKzgProof(
   z: BLSFieldElement,
   y: BLSFieldElement,
   kzgProof: KZGProof
-) {
+): boolean {
   if (!setupHandle) {
     throw new Error("You must call loadTrustedSetup to initialize KZG.");
   }

bindings/node.js/test.ts

@@ -2,46 +2,43 @@ import { randomBytes } from "crypto";
 import {
   loadTrustedSetup,
   freeTrustedSetup,
-  verifyKzgProof,
   blobToKzgCommitment,
-  Blob,
-  BLOB_SIZE,
-  NUMBER_OF_FIELDS,
   computeAggregateKzgProof,
   verifyAggregateKzgProof,
+  BYTES_PER_FIELD,
+  FIELD_ELEMENTS_PER_BLOB,
+  verifyKzgProof,
 } from "./kzg";
 
 const SETUP_FILE_PATH = "../../src/trusted_setup.txt";
+const BLOB_BYTE_COUNT = FIELD_ELEMENTS_PER_BLOB * BYTES_PER_FIELD;
 
-function generateRandomBlob(): Blob {
+const generateRandomBlob = () => new Uint8Array(randomBytes(BLOB_BYTE_COUNT));
-  return new Uint8Array(randomBytes(BLOB_SIZE * NUMBER_OF_FIELDS));
-}
 
 describe("C-KZG", () => {
-  beforeEach(() => {
+  beforeAll(() => {
     loadTrustedSetup(SETUP_FILE_PATH);
   });
 
-  afterEach(() => {
+  afterAll(() => {
     freeTrustedSetup();
   });
 
-  it("computes and verifies an aggregate KZG proof", async () => {
+  it.skip("verifies a proof at a given commitment point", async () => {
-    const blob1 = generateRandomBlob();
+    const blob = generateRandomBlob();
-    const blob2 = generateRandomBlob();
+    const commitment = blobToKzgCommitment(blob);
-    const blobs = [blob1, blob2];
+    const proof = computeAggregateKzgProof([blob]);
 
+    const z = Uint8Array.from(new Array(32).fill(0));
+    const y = Uint8Array.from(new Array(32).fill(0));
+
+    expect(verifyKzgProof(commitment, z, y, proof)).toBe(true);
+  });
+
+  it("computes the correct aggregate commitment from blobs", async () => {
+    const blobs = new Array(2).fill(0).map(generateRandomBlob);
     const commitments = blobs.map(blobToKzgCommitment);
-
     const proof = computeAggregateKzgProof(blobs);
-
+    expect(verifyAggregateKzgProof(blobs, commitments, proof)).toBe(true);
-    console.log({
-      commitments,
-      proof,
-    });
-
-    const result = verifyAggregateKzgProof(blobs, commitments, proof);
-
-    expect(result).toBe(true);
   });
 });

src/Makefile

@@ -1,7 +1,7 @@
 INCLUDE_DIRS = ../inc
 CFLAGS += -O2
 
-c_kzg_4844.o: c_kzg_4844.c Makefile
+c_kzg_4844.o: c_kzg_4844.c sha256.c Makefile
 	clang -Wall -I$(INCLUDE_DIRS) $(CFLAGS) -c c_kzg_4844.c sha256.c
 
 lib: c_kzg_4844.o Makefile