diff --git a/.gitignore b/.gitignore
index d06a9ff..37f18f1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,5 @@
 .vscode
 node_modules/
-.env
\ No newline at end of file
+.env
+.env.kovan
+.env.mainnet
\ No newline at end of file
diff --git a/index.js b/index.js
index 5172e62..2185282 100644
--- a/index.js
+++ b/index.js
@@ -44,7 +44,7 @@ app.post('/relay', async (req, resp) => {
   let { valid , reason } = isValidProof(req.body.proof)
   if (!valid) {
     console.log('Proof is invalid:', reason)
-    return resp.status(400).json({ error: 'Proof is invalid' })
+    return resp.status(400).json({ error: 'Proof format is invalid' })
   }
 
   let currency
@@ -55,51 +55,54 @@ app.post('/relay', async (req, resp) => {
   }
 
   let { proof, publicSignals } = req.body.proof
-  
-  const relayer = toChecksumAddress(`0x${publicSignals[3].slice(26)}`)
-  if (relayer !== web3.eth.defaultAccount) {
-    console.log('This proof is for different relayer:', relayer)
+  const args = {
+    root: publicSignals[0],
+    nullifierHash: publicSignals[1],
+    recipient: toChecksumAddress(publicSignals[2]),
+    relayer: toChecksumAddress(publicSignals[3]),
+    fee: toBN(publicSignals[4]),
+    refund: toBN(publicSignals[5]),
+  }
+
+  if (args.relayer !== web3.eth.defaultAccount) {
+    console.log('This proof is for different relayer:', args.relayer)
     return resp.status(400).json({ error: 'Relayer address is invalid' })
   }
 
-  const fee = toBN(publicSignals[4])
-  const refund = toBN(publicSignals[5])
   const expense = toBN(toWei(gasPrices.fast.toString(), 'gwei')).mul(toBN('1000000'))
   let desiredFee
   switch (currency) {
     case 'eth': {
-      if (!refund.isZero()) {
+      if (!args.refund.isZero()) {
         return resp.status(400).json({ error: 'Cannot send refund for eth currency.' })
       }
       desiredFee = expense
       break
     }
     case 'dai': {
-      desiredFee = expense.add(refund).mul(toBN(ethPriceInDai)).div(toBN(10 ** 18))
+      desiredFee = expense.add(args.refund).mul(toBN(ethPriceInDai)).div(toBN(10 ** 18))
       break
     }
   }
 
-  if (fee.lt(desiredFee)) {
+  if (args.fee.lt(desiredFee)) {
     console.log('Fee is too low')
     return resp.status(400).json({ error: 'Fee is too low. Try to resend.' })
   }
 
   try {
     const mixer = new web3.eth.Contract(mixerABI, req.body.contract)
-    const nullifier = publicSignals[1]
-    const isSpent = await mixer.methods.isSpent(nullifier).call()
+    const isSpent = await mixer.methods.isSpent(args.nullifierHash).call()
     if (isSpent) {
       return resp.status(400).json({ error: 'The note has been spent.' })
     }
-    const root = publicSignals[0]
-    const isKnownRoot = await mixer.methods.isKnownRoot(root).call()
+    const isKnownRoot = await mixer.methods.isKnownRoot(args.root).call()
     if (!isKnownRoot) {
       return resp.status(400).json({ error: 'The merkle root is too old or invalid.' })
     }
-    const gas = await mixer.methods.withdraw(proof, publicSignals).estimateGas({ value: refund })
-    const result = mixer.methods.withdraw(proof, publicSignals).send({
-      value: refund,
+    const gas = await mixer.methods.withdraw(proof, ...publicSignals).estimateGas({ value: args.refund })
+    const result = mixer.methods.withdraw(proof, ...publicSignals).send({
+      value: args.refund,
       gas: numberToHex(gas + 50000),
       gasPrice: toHex(toWei(gasPrices.fast.toString(), 'gwei')),
       // TODO: nonce
diff --git a/utils.js b/utils.js
index 2c99f8d..af8299b 100644
--- a/utils.js
+++ b/utils.js
@@ -42,34 +42,36 @@ async function fetchDAIprice({ ethPriceInDai, web3 }) {
   }
 }
 
-function isValidProof(proof) {
+function isValidProof(data) {
   // validator expects `websnarkUtils.toSolidityInput(proof)` output
 
-  if (!(proof.proof && proof.publicSignals)) {
+  if (!(data.proof && data.publicSignals)) {
     return { valid: false, reason: 'One of inputs is empty. There must be proof and publicSignals' }
   }
 
-  Object.keys(proof).forEach(key => {
-    if (!Array.isArray(proof[key])) {
-      return { valid: false, reason: `Corrupted ${key}` }
-    }
-  })
-
-  if (proof.proof.length !== 8) {
+  if (!isHexStrict(data.proof) || data.proof.length !== 2 + 2 * 8 * 32) {
     return { valid: false, reason: 'Corrupted proof' }
   }
 
-  if (proof.publicSignals.length !== 6) {
+  if (data.publicSignals.length !== 6) {
     return { valid: false, reason: 'Corrupted publicSignals' }
   }
 
-  for (let [key, input] of Object.entries(proof)) {
-    for (let i = 0; i < input.length; i++ ) {
-      if (!isHexStrict(input[i]) || input[i].length !== 66) {
-        return { valid: false, reason: `Corrupted ${key}` }
-      }
+  for(let signal of data.publicSignals) {
+    if (!isHexStrict(signal)) {
+      return { valid: false, reason: 'Corrupted publicSignals' }
     }
   }
+
+  if (data.publicSignals[0].length !== 66 ||
+      data.publicSignals[1].length !== 66 ||
+      data.publicSignals[2].length !== 42 ||
+      data.publicSignals[3].length !== 42 ||
+      data.publicSignals[4].length !== 66 ||
+      data.publicSignals[5].length !== 66) {
+    return { valid: false, reason: 'Corrupted publicSignals' }
+  }
+
   return { valid: true }
 }