Merge pull request #47 from 0xPolygonHermez/feature/update-snark-input

update calculateSnarkInput to match pil-stark
0xPolygonHermez · Aug 5, 2022 · 2f0c0fb · 2f0c0fb
2 parents 7d7d858 + 440469e
commit 2f0c0fb
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Showing 6 changed files with 142 additions and 96 deletions.
diff --git a/package.json b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "@0xpolygonhermez/zkevm-commonjs",
   "description": "Javascript library implementing common utilities for zkevm",
-  "version": "0.0.37",
+  "version": "0.0.38",
   "main": "index.js",
   "scripts": {
     "setup": "npm i",

diff --git a/src/contract-utils.js b/src/contract-utils.js
@@ -1,6 +1,8 @@
 const ethers = require('ethers');
 const { Scalar } = require('ffjavascript');
-const { FrSNARK } = require('./constants');
+const { sha256Snark, padZeros } = require('./utils');
+const { string2fea } = require('./smt-utils');
+const getPoseidon = require('./poseidon');
 
 /**
  * Compute globalHash for STARK circuit
@@ -55,7 +57,7 @@ function calculateStarkInput(
  * @param {String} aggregatorAddress - Aggregator Ethereum address in hex string
  * @returns {String} - sha256(globalHash, aggregatorAddress) % FrSNARK in hex encoding
  */
-function calculateSnarkInput(
+async function calculateSnarkInput(
     currentStateRoot,
     currentLocalExitRoot,
     newStateRoot,
@@ -65,6 +67,9 @@ function calculateSnarkInput(
     timestamp,
     aggregatorAddress,
 ) {
+    const poseidon = await getPoseidon();
+    const { F } = poseidon;
+
     const hashKeccak = calculateStarkInput(
         currentStateRoot,
         currentLocalExitRoot,
@@ -75,15 +80,20 @@ function calculateSnarkInput(
         timestamp,
     );
 
-    const hashSha256 = ethers.utils.soliditySha256(
-        ['bytes32', 'address'],
-        [
-            hashKeccak,
-            aggregatorAddress,
-        ],
+    // 20 bytes agggregator adsress
+    const strAggregatorAddress = padZeros((Scalar.fromString(aggregatorAddress, 16)).toString(16), 40);
+
+    // 8 bytes each field element
+    const feaHashKeccak = string2fea(F, hashKeccak);
+    const strFea = feaHashKeccak.reduce(
+        (previousValue, currentValue) => previousValue + padZeros(currentValue.toString(16), 16),
+        '',
     );
 
-    return `0x${Scalar.mod(Scalar.fromString(hashSha256, 16), FrSNARK).toString(16).padStart(64, '0')}`;
+    // build final bytes sha256
+    const finalStr = strAggregatorAddress.concat(strFea);
+
+    return sha256Snark(finalStr);
 }
 
 /**

diff --git a/src/utils.js b/src/utils.js
@@ -1,4 +1,8 @@
 /* eslint-disable no-restricted-syntax */
+const crypto = require('crypto');
+const { Scalar } = require('ffjavascript');
+const { FrSNARK } = require('./constants');
+
 /**
  * Log2 function
  * @param {Number} V - value
@@ -48,8 +52,38 @@ function hexString2byteArray(_hex) {
     return byteArray;
 }
 
+/**
+ * Pad a string hex number with 0
+ * @param {String} str - String input
+ * @param {Number} length - Length of the resulting string
+ * @returns {String} Resulting string
+ */
+function padZeros(str, length) {
+    if (length > str.length) {
+        str = '0'.repeat(length - str.length) + str;
+    }
+
+    return str;
+}
+
+/**
+ * (Hash Sha256 of an hexadecimal string) % (Snark field)
+ * @param {String} str - String input in hexadecimal encoding
+ * @returns {Scalar} Resulting sha256 hash
+ */
+function sha256Snark(str) {
+    const hash = crypto.createHash('sha256')
+        .update(str, 'hex')
+        .digest('hex');
+    const h = Scalar.mod(Scalar.fromString(hash, 16), FrSNARK);
+
+    return h;
+}
+
 module.exports = {
     log2,
     byteArray2HexString,
     hexString2byteArray,
+    sha256Snark,
+    padZeros,
 };
diff --git a/test/contract-utils.test.js b/test/contract-utils.test.js
@@ -11,12 +11,13 @@ describe('contractUtils', function () {
     this.timeout(10000);
     let testVector;
 
-    const expectedBatchHashData = '0xa4e1166ff3f7ecf8c8ff3049fc2e28b03091d3bf0db4bce702d954840196f79d';
-    const expectedSnarkInputHash = '0x0b0a9c614cdc5473f2a9251d171230e92e5ae31fab0b165b13586100dad3a2c0';
-    const expectedStarkHashExecutor = '0x73855bab378977b439591bdee0bbde9c1b1cf3f48e20418da906ab7abfcc42cf';
+    const expectedBatchHashData = '0x9370689d3c20a5a4739f902a31e2ea20c7d7be121a0fc19468a2e1b5d87f4111';
+    // input taken from pil-stark
+    const expectedSnarkInputHash = '14918438705377636817563619860509474434188349281706594260803853913155748736842';
+    const expectedStarkHashExecutor = '0xd072c5e95f2a1aa8dee6f1e0667f72f9e66ed47f7ff5f5e3ad6f504379c73c26';
 
     before(async () => {
-        testVector = JSON.parse(fs.readFileSync(path.join(pathTestVectors, 'inputs-executor/input_0.json')));
+        testVector = JSON.parse(fs.readFileSync(path.join(pathTestVectors, 'inputs-executor/input_executor.json')));
     });
 
     it('calculateBatchHashData', async () => {
@@ -34,7 +35,7 @@ describe('contractUtils', function () {
     });
 
     it('calculateSnarkInput', async () => {
-        const aggregatorAddress = '0x123456789ABCDDEF123456789ABCDDEF12345678';
+        const aggregatorAddress = '0xf39fd6e51aad88f6f4ce6ab8827279cfffb92266';
 
         const {
             oldLocalExitRoot,
@@ -45,7 +46,7 @@ describe('contractUtils', function () {
             timestamp,
         } = testVector;
 
-        const computedGlobalHash = await contractUtils.calculateSnarkInput(
+        const computedSnark = await contractUtils.calculateSnarkInput(
             oldStateRoot,
             oldLocalExitRoot,
             newStateRoot,
@@ -56,7 +57,7 @@ describe('contractUtils', function () {
             aggregatorAddress,
         );
 
-        expect(computedGlobalHash).to.be.equal(expectedSnarkInputHash);
+        expect(computedSnark.toString()).to.be.equal(expectedSnarkInputHash.toString());
     });
 
     it('calculateStarkInput', async () => {

diff --git a/test/helpers/test-vectors/inputs-executor/input_0.json b/test/helpers/test-vectors/inputs-executor/input_0.json
diff --git a/test/helpers/test-vectors/inputs-executor/input_executor.json b/test/helpers/test-vectors/inputs-executor/input_executor.json
@@ -0,0 +1,80 @@
+{
+  "oldStateRoot": "0x2dc4db4293af236cb329700be43f08ace740a05088f8c7654736871709687e90",
+  "db": {
+    "0x2dc4db4293af236cb329700be43f08ace740a05088f8c7654736871709687e90": [
+      "0000000000000000",
+      "0000000000000000",
+      "0000000000000000",
+      "0000000000000000",
+      "0d1f0da5a7b620c8",
+      "43fd1e18e59fd724",
+      "d428d25da0cb1888",
+      "e31f5542ac227c06",
+      "0000000000000000",
+      "0000000000000000",
+      "0000000000000000",
+      "0000000000000000"
+    ],
+    "0xe31f5542ac227c06d428d25da0cb188843fd1e18e59fd7240d1f0da5a7b620c8": [
+      "ed22ec7734d89ff2",
+      "b2e639153607b7c5",
+      "42b2bd6ec2788851",
+      "b781932941084783",
+      "3e63658ee0db910d",
+      "0b3e34316e81aa10",
+      "e0dc203d93f4e3e5",
+      "e10053d0ebc64602",
+      "0000000000000000",
+      "0000000000000000",
+      "0000000000000000",
+      "0000000000000000"
+    ],
+    "0xb78193294108478342b2bd6ec2788851b2e639153607b7c5ed22ec7734d89ff2": [
+      "16dde42596b907f0",
+      "49015d7e991a1528",
+      "94dd9dadd060910b",
+      "60b4d5e9af514018",
+      "b69b044f5e694795",
+      "f57d81efba5d4445",
+      "339438195426ad0a",
+      "3efad1dd58c2259d",
+      "0000000000000001",
+      "0000000000000000",
+      "0000000000000000",
+      "0000000000000000"
+    ],
+    "0x3efad1dd58c2259d339438195426ad0af57d81efba5d4445b69b044f5e694795": [
+      "00000000dea00000",
+      "0000000035c9adc5",
+      "0000000000000036",
+      "0000000000000000",
+      "0000000000000000",
+      "0000000000000000",
+      "0000000000000000",
+      "0000000000000000"
+    ],
+    "0xe10053d0ebc64602e0dc203d93f4e3e50b3e34316e81aa103e63658ee0db910d": [
+      "66ee2be0687eea76",
+      "6926f8ca8796c78a",
+      "4c2f3e938869b82d",
+      "649e63bfe1247ba4",
+      "b69b044f5e694795",
+      "f57d81efba5d4445",
+      "339438195426ad0a",
+      "3efad1dd58c2259d",
+      "0000000000000001",
+      "0000000000000000",
+      "0000000000000000",
+      "0000000000000000"
+    ]
+  },
+  "sequencerAddr": "0x617b3a3528F9cDd6630fd3301B9c8911F7Bf063D",
+  "batchL2Data": "0xee80843b9aca00830186a0944d5cf5032b2a844602278b01199ed191a86c93ff88016345785d8a0000808203e880801cee7e01dc62f69a12c3510c6d64de04ee6346d84b6a017f3e786c7d87f963e75d8cc91fa983cd6d9cf55fff80d73bd26cd333b0f098acc1e58edb1fd484ad731b",
+  "newStateRoot": "0xbff23fc2c168c033aaac77503ce18f958e9689d5cdaebb88c5524ce5c0319de3",
+  "oldLocalExitRoot": "0x17c04c3760510b48c6012742c540a81aba4bca2f78b9d14bfd2f123e2e53ea3e",
+  "newLocalExitRoot": "0x0000000000000000000000000000000000000000000000000000000000000000",
+  "globalExitRoot": "0x090bcaf734c4f06c93954a827b45a6e8c67b8e0fd1e0a35a1c5982d6961828f9",
+  "numBatch": 1,
+  "timestamp": 1944498031,
+  "contractsBytecode": {}
+}