From a520e3c0f44f8496536c76f4b13dcaa83a9880c2 Mon Sep 17 00:00:00 2001
From: Saleel <saleel@saleel.xyz>
Date: Fri, 17 May 2024 08:08:09 +0400
Subject: [PATCH] helpers: add poseidonLarge JS version

---
 packages/circuits/tests/email-verifier.test.ts |  8 +++-----
 packages/helpers/src/hash.ts                   | 10 ++++++++++
 scripts/dkim/update-dkim-registry.ts           |  8 ++++----
 3 files changed, 17 insertions(+), 9 deletions(-)
 create mode 100644 packages/helpers/src/hash.ts

diff --git a/packages/circuits/tests/email-verifier.test.ts b/packages/circuits/tests/email-verifier.test.ts
index 6aad3ccb7..b87a02235 100644
--- a/packages/circuits/tests/email-verifier.test.ts
+++ b/packages/circuits/tests/email-verifier.test.ts
@@ -5,7 +5,7 @@ import path from "path";
 import { DKIMVerificationResult } from "@zk-email/helpers/src/dkim";
 import { generateEmailVerifierInputsFromDKIMResult } from "@zk-email/helpers/src/input-generators";
 import { verifyDKIMSignature } from "@zk-email/helpers/src/dkim";
-import { bigIntToChunkedBytes } from "@zk-email/helpers/src/binary-format";
+import { poseidonLarge } from "@zk-email/helpers/src/hash";
 
 
 describe("EmailVerifier", () => {
@@ -169,15 +169,13 @@ describe("EmailVerifier", () => {
     });
 
     // Calculate the Poseidon hash with pubkey chunked to 9*242 like in circuit
-    const poseidon = await buildPoseidon();
-    const pubkeyChunked = bigIntToChunkedBytes(dkimResult.publicKey, 242, 9);
-    const hash = poseidon(pubkeyChunked);
+    const poseidonHash = await poseidonLarge(dkimResult.publicKey, 9, 242);
 
     // Calculate the hash using the circuit
     const witness = await circuit.calculateWitness(emailVerifierInputs);
 
     await circuit.assertOut(witness, {
-      pubkeyHash: poseidon.F.toObject(hash),
+      pubkeyHash: poseidonHash,
     });
   });
 });
diff --git a/packages/helpers/src/hash.ts b/packages/helpers/src/hash.ts
new file mode 100644
index 000000000..c5b662f6a
--- /dev/null
+++ b/packages/helpers/src/hash.ts
@@ -0,0 +1,10 @@
+import { buildPoseidon } from 'circomlibjs';
+import { bigIntToChunkedBytes } from './binary-format';
+
+export async function poseidonLarge(input: bigint, numChunks: number, bitsPerChunk: number) {
+  const poseidon = await buildPoseidon();
+  const pubkeyChunked = bigIntToChunkedBytes(input, bitsPerChunk, numChunks);
+  const hash = poseidon(pubkeyChunked);
+
+  return poseidon.F.toObject(hash) as Promise<bigint>;
+}
diff --git a/scripts/dkim/update-dkim-registry.ts b/scripts/dkim/update-dkim-registry.ts
index 9bc649358..9bd1ef5b9 100644
--- a/scripts/dkim/update-dkim-registry.ts
+++ b/scripts/dkim/update-dkim-registry.ts
@@ -6,6 +6,7 @@ import forge from "node-forge";
 import { bigIntToChunkedBytes } from "@zk-email/helpers/src/binaryFormat";
 const fs = require("fs");
 import { abi } from "../abis/DKIMRegistry.json";
+import { poseidonLarge } from "@zk-email/helpers/src/hash";
 require("dotenv").config();
 
 async function updateContract(domain: string, pubkeyHashes: string[]) {
@@ -252,16 +253,15 @@ async function updateDKIMRegistry({
 
   // Generate pub key hash using 242 * 9 chunks (Poseidon lib don't take more than 16 inputs)
   const domainHashedPubKeyMap: { [key: string]: string[] } = {};
-  const poseidon = await buildPoseidon();
+
   for (let domain of Object.keys(domainPubKeyMap)) {
     for (let { publicKey } of domainPubKeyMap[domain]) {
-      const pubkeyChunked = bigIntToChunkedBytes(BigInt(publicKey), 242, 9);
-      const hash = poseidon(pubkeyChunked);
+      const poseidonHash = await poseidonLarge(BigInt(publicKey), 9, 242);
 
       if (!domainHashedPubKeyMap[domain]) {
         domainHashedPubKeyMap[domain] = [];
       }
-      domainHashedPubKeyMap[domain].push(poseidon.F.toObject(hash).toString());
+      domainHashedPubKeyMap[domain].push(poseidonHash.toString());
     }
   }
   _writeToFile("dkim-keys-hashed.json", domainHashedPubKeyMap);