decouple hash utils

src/byte_utils.ts

@@ -1,63 +0,0 @@
-// Adapted from https://github.com/feross/buffer
-
-function checkInt(
-  buf: Uint8Array,
-  value: number,
-  offset: number,
-  ext: number,
-  max: number,
-  min: number
-): void {
-  if (value > max || value < min)
-    throw new RangeError('"value" argument is out of bounds');
-  if (offset + ext > buf.length) throw new RangeError("Index out of range");
-}
-
-export function writeUIntLE(
-  buf: Uint8Array,
-  value: number,
-  offset: number,
-  byteLength: number,
-  noAssert?: boolean
-): Uint8Array {
-  value = +value;
-  offset = offset >>> 0;
-  byteLength = byteLength >>> 0;
-  if (!noAssert) {
-    const maxBytes = Math.pow(2, 8 * byteLength) - 1;
-    checkInt(buf, value, offset, byteLength, maxBytes, 0);
-  }
-
-  let mul = 1;
-  let i = 0;
-  buf[offset] = value & 0xff;
-  while (++i < byteLength && (mul *= 0x100)) {
-    buf[offset + i] = (value / mul) & 0xff;
-  }
-
-  return buf;
-}
-
-/**
- * Transforms Uint8Array into BigInt
- * @param array: Uint8Array
- * @returns BigInt
- */
-export function buildBigIntFromUint8Array(array: Uint8Array): bigint {
-  const dataView = new DataView(array.buffer);
-  return dataView.getBigUint64(0, true);
-}
-
-/**
- * Fills with zeros to set length
- * @param array little endian Uint8Array
- * @param length amount to pad
- * @returns little endian Uint8Array padded with zeros to set length
- */
-export function zeroPadLE(array: Uint8Array, length: number): Uint8Array {
-  const result = new Uint8Array(length);
-  for (let i = 0; i < length; i++) {
-    result[i] = array[i] || 0;
-  }
-  return result;
-}

src/contract/rln_contract.ts

@@ -1,7 +1,8 @@
 import { hexToBytes } from "@waku/utils/bytes";
 import { ethers } from "ethers";
 
-import { zeroPadLE } from "./byte_utils.js";
+import { zeroPadLE } from "../utils/index.js";
+
 import { RLN_REGISTRY_ABI, RLN_STORAGE_ABI } from "./constants.js";
 import type { DecryptedCredentials } from "./keystore/index.js";
 import { type IdentityCredential, RLNInstance } from "./rln.js";

src/rln.ts

@@ -9,7 +9,6 @@ import init from "@waku/zerokit-rln-wasm";
 import * as zerokitRLN from "@waku/zerokit-rln-wasm";
 import { ethers } from "ethers";
 
-import { buildBigIntFromUint8Array, writeUIntLE } from "./byte_utils.js";
 import type { RLNDecoder, RLNEncoder } from "./codec.js";
 import { createRLNDecoder, createRLNEncoder } from "./codec.js";
 import { SEPOLIA_CONTRACT } from "./constants.js";
@@ -22,6 +21,11 @@ import type {
 } from "./keystore/index.js";
 import { KeystoreEntity, Password } from "./keystore/types.js";
 import verificationKey from "./resources/verification_key.js";
+import {
+  buildBigIntFromUint8Array,
+  poseidonHash,
+  writeUIntLE,
+} from "./utils/index.js";
 import { concatenate, extractMetaMaskSigner } from "./utils/index.js";
 import * as wc from "./witness_calculator.js";
 import { WitnessCalculator } from "./witness_calculator.js";
@@ -147,18 +151,6 @@ export function proofToBytes(p: IRateLimitProof): Uint8Array {
   );
 }
 
-export function poseidonHash(...input: Array<Uint8Array>): Uint8Array {
-  const inputLen = writeUIntLE(new Uint8Array(8), input.length, 0, 8);
-  const lenPrefixedData = concatenate(inputLen, ...input);
-  return zerokitRLN.poseidonHash(lenPrefixedData);
-}
-
-export function sha256(input: Uint8Array): Uint8Array {
-  const inputLen = writeUIntLE(new Uint8Array(8), input.length, 0, 8);
-  const lenPrefixedData = concatenate(inputLen, input);
-  return zerokitRLN.hash(lenPrefixedData);
-}
-
 type StartRLNOptions = {
   /**
    * If not set - will extract MetaMask account and get signer from it.

src/utils/bytes.ts

@@ -16,3 +16,66 @@ export function concatenate(...input: Uint8Array[]): Uint8Array {
   }
   return result;
 }
+
+// Adapted from https://github.com/feross/buffer
+function checkInt(
+  buf: Uint8Array,
+  value: number,
+  offset: number,
+  ext: number,
+  max: number,
+  min: number
+): void {
+  if (value > max || value < min)
+    throw new RangeError('"value" argument is out of bounds');
+  if (offset + ext > buf.length) throw new RangeError("Index out of range");
+}
+
+export function writeUIntLE(
+  buf: Uint8Array,
+  value: number,
+  offset: number,
+  byteLength: number,
+  noAssert?: boolean
+): Uint8Array {
+  value = +value;
+  offset = offset >>> 0;
+  byteLength = byteLength >>> 0;
+  if (!noAssert) {
+    const maxBytes = Math.pow(2, 8 * byteLength) - 1;
+    checkInt(buf, value, offset, byteLength, maxBytes, 0);
+  }
+
+  let mul = 1;
+  let i = 0;
+  buf[offset] = value & 0xff;
+  while (++i < byteLength && (mul *= 0x100)) {
+    buf[offset + i] = (value / mul) & 0xff;
+  }
+
+  return buf;
+}
+
+/**
+ * Transforms Uint8Array into BigInt
+ * @param array: Uint8Array
+ * @returns BigInt
+ */
+export function buildBigIntFromUint8Array(array: Uint8Array): bigint {
+  const dataView = new DataView(array.buffer);
+  return dataView.getBigUint64(0, true);
+}
+
+/**
+ * Fills with zeros to set length
+ * @param array little endian Uint8Array
+ * @param length amount to pad
+ * @returns little endian Uint8Array padded with zeros to set length
+ */
+export function zeroPadLE(array: Uint8Array, length: number): Uint8Array {
+  const result = new Uint8Array(length);
+  for (let i = 0; i < length; i++) {
+    result[i] = array[i] || 0;
+  }
+  return result;
+}

src/utils/hash.ts

@@ -0,0 +1,15 @@
+import * as zerokitRLN from "@waku/zerokit-rln-wasm";
+
+import { concatenate, writeUIntLE } from "./bytes.js";
+
+export function poseidonHash(...input: Array<Uint8Array>): Uint8Array {
+  const inputLen = writeUIntLE(new Uint8Array(8), input.length, 0, 8);
+  const lenPrefixedData = concatenate(inputLen, ...input);
+  return zerokitRLN.poseidonHash(lenPrefixedData);
+}
+
+export function sha256(input: Uint8Array): Uint8Array {
+  const inputLen = writeUIntLE(new Uint8Array(8), input.length, 0, 8);
+  const lenPrefixedData = concatenate(inputLen, input);
+  return zerokitRLN.hash(lenPrefixedData);
+}

src/utils/index.ts

@@ -1,2 +1,8 @@
 export { extractMetaMaskSigner } from "./metamask.js";
-export { concatenate } from "./bytes.js";
+export {
+  concatenate,
+  writeUIntLE,
+  buildBigIntFromUint8Array,
+  zeroPadLE,
+} from "./bytes.js";
+export { sha256, poseidonHash } from "./hash.js";