test for compliance

src/index.js

@@ -150,4 +150,4 @@ async function registerAndTransact({ tornadoPool, account, ...rest }) {
   await receipt.wait()
 }
 
-module.exports = { transaction, registerAndTransact, prepareTransaction }
+module.exports = { transaction, registerAndTransact, prepareTransaction, buildMerkleTree }

test/full.test.js

@@ -5,7 +5,8 @@ const { expect } = require('chai')
 const { utils } = ethers
 
 const Utxo = require('../src/utxo')
-const { transaction, registerAndTransact, prepareTransaction } = require('../src/index')
+const { transaction, registerAndTransact, prepareTransaction, buildMerkleTree } = require('../src/index')
+const { toFixedHex, poseidonHash } = require('../src/utils')
 const { Keypair } = require('../src/keypair')
 const { encodeDataForBridge } = require('./utils')
 
@@ -336,4 +337,66 @@ describe('TornadoPool', function () {
       outputs: [aliceDepositUtxo],
     })
   })
+
+  it('should be compliant', async function () {
+    // basically verifier should check if a commitment and a nullifier hash are on chain
+    const { tornadoPool } = await loadFixture(fixture)
+    const aliceDepositAmount = utils.parseEther('0.07')
+    const aliceDepositUtxo = new Utxo({ amount: aliceDepositAmount })
+    const [sender] = await ethers.getSigners()
+
+    const { args, extData } = await prepareTransaction({
+      tornadoPool,
+      outputs: [aliceDepositUtxo],
+    })
+    const receipt = await tornadoPool.transact(args, extData, {
+      gasLimit: 2e6,
+    })
+    await receipt.wait()
+
+    // withdrawal
+    await transaction({
+      tornadoPool,
+      inputs: [aliceDepositUtxo],
+      outputs: [],
+      recipient: sender.address,
+    })
+
+    const tree = await buildMerkleTree({ tornadoPool })
+    const commitment = aliceDepositUtxo.getCommitment()
+    const index = tree.indexOf(toFixedHex(commitment)) // it's the same as merklePath and merklePathIndexes and index in the tree
+    aliceDepositUtxo.index = index
+    const nullifier = aliceDepositUtxo.getNullifier()
+
+    // commitment = hash(amount, pubKey, blinding)
+    // nullifier = hash(commitment, merklePath, sign(merklePath, privKey))
+    const dataForVerifier = {
+      commitment: {
+        amount: aliceDepositUtxo.amount,
+        pubkey: aliceDepositUtxo.keypair.pubkey,
+        blinding: aliceDepositUtxo.blinding,
+      },
+      nullifier: {
+        merklePath: index,
+        signature: aliceDepositUtxo.keypair.sign(index),
+      },
+    }
+
+    // generateReport(dataForVerifier) -> compliance report
+    // on the verifier side we compute commitment and nullifier and then check them onchain
+    const commitmentV = poseidonHash([...Object.values(dataForVerifier.commitment)])
+    const nullifierV = poseidonHash([
+      commitmentV,
+      dataForVerifier.nullifier.merklePath,
+      dataForVerifier.nullifier.signature,
+    ])
+
+    expect(commitmentV).to.be.equal(commitment)
+    expect(nullifierV).to.be.equal(nullifier)
+    expect(await tornadoPool.nullifierHashes(nullifierV)).to.be.equal(true)
+    // expect commitmentV present onchain (it will be in NewCommitment events)
+
+    // in report we can see the tx with NewCommitment event (this is how alice got money)
+    // and the tx with NewNullifier event is where alice spent the UTXO
+  })
 })