fix: build uint256 instead of uint64 for commitment id

src/identity.ts

@@ -1,4 +1,4 @@
-import { buildBigIntFromUint8Array } from "./utils/index.js";
+import { uint256FromBytes } from "./utils/bytes.js";
 
 export class IdentityCredential {
   constructor(
@@ -14,7 +14,7 @@ export class IdentityCredential {
     const idNullifier = memKeys.subarray(32, 64);
     const idSecretHash = memKeys.subarray(64, 96);
     const idCommitment = memKeys.subarray(96);
-    const idCommitmentBigInt = buildBigIntFromUint8Array(idCommitment, 96);
+    const idCommitmentBigInt = uint256FromBytes(idCommitment);
 
     return new IdentityCredential(
       idTrapdoor,

src/keystore/keystore.ts

@@ -14,7 +14,7 @@ import {
 import _ from "lodash";
 import { v4 as uuidV4 } from "uuid";
 
-import { buildBigIntFromUint8Array } from "../utils/bytes.js";
+import { uint256FromBytes } from "../utils/bytes.js";
 
 import { decryptEipKeystore, keccak256Checksum } from "./cipher.js";
 import { isCredentialValid, isKeystoreValid } from "./schema_validator.js";
@@ -262,7 +262,7 @@ export class Keystore {
           IDNullifier: Keystore.fromArraylikeToBytes(
             _.get(obj, "identityCredential.idNullifier", [])
           ),
-          IDCommitmentBigInt: buildBigIntFromUint8Array(
+          IDCommitmentBigInt: uint256FromBytes(
             Keystore.fromArraylikeToBytes(
               _.get(obj, "identityCredential.idCommitment", [])
             )

src/utils/bytes.ts

@@ -69,6 +69,19 @@ export function buildBigIntFromUint8Array(
   return dataView.getBigUint64(byteOffset, true);
 }
 
+export function uint256FromBytes(bytes: Uint8Array): bigint {
+  if (bytes.length !== 32) {
+    throw new Error("Invalid uint256 byte length");
+  }
+
+  let value = BigInt(0);
+  for (let i = 0; i < 32; i++) {
+    value |= BigInt(bytes[i]) << BigInt(i * 8);
+  }
+
+  return value as bigint;
+}
+
 /**
  * Fills with zeros to set length
  * @param array little endian Uint8Array

src/zerokit.ts

@@ -119,7 +119,7 @@ export class Zerokit {
         "zerokit/rln/010203040506070809"
       );
 
-      const fetchUrl = `${process.env.MERKLE_PROOF_SERVICE_URL || "http://localhost:8645/debug/v1/merkleProof"}/${idCommitment}`;
+      const fetchUrl = `http://localhost:8645/debug/v1/merkleProof/${idCommitment}`;
       const response = await fetch(fetchUrl);
 
       const proofData = await response.json();