diff --git a/lib/Permit.js b/lib/Permit.js
index ce5d3b1..4859de6 100644
--- a/lib/Permit.js
+++ b/lib/Permit.js
@@ -1,6 +1,6 @@
-const { EIP712Signer } = require('@ticket721/e712')
+import { concatSig } from 'eth-sig-util'
 
-const Permit = [
+const PermitType = [
   { name: 'owner', type: 'address' },
   { name: 'spender', type: 'address' },
   { name: 'value', type: 'uint256' },
@@ -8,36 +8,53 @@ const Permit = [
   { name: 'deadline', type: 'uint256' }
 ]
 
-class PermitSigner extends EIP712Signer {
+const EIP712DomainType = [
+  { name: 'name', type: 'string' },
+  { name: 'version', type: 'string' },
+  { name: 'chainId', type: 'uint256' },
+  { name: 'verifyingContract', type: 'address' }
+]
+
+export default class PermitSigner {
   constructor(_domain, _permitArgs) {
-    super(_domain, ['Permit', Permit])
     this.permitArgs = _permitArgs
+    this.domain = _domain
   }
 
-  // Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)
   setPermitInfo(_permitArgs) {
     this.permitArgs = _permitArgs
   }
 
-  getPayload() {
-    return this.generatePayload(this.permitArgs, 'Permit')
-  }
-
-  async getSignature(privateKey) {
-    const payload = this.getPayload()
-    const { hex, v, r, s } = await this.sign(privateKey, payload)
+  getReqPayload() {
     return {
-      hex,
-      v,
-      r: '0x' + r,
-      s: '0x' + s
+      domain: this.domain,
+      primaryType: 'Permit',
+      types: {
+        Permit: PermitType,
+        EIP712Domain: EIP712DomainType
+      },
+      message: this.permitArgs
     }
   }
 
-  getSignerAddress(permitArgs, signature) {
-    const originalPayload = this.generatePayload(permitArgs, 'Permit')
-    return this.verify(originalPayload, signature)
+  getSignature(response) {
+    response = response.substring(2)
+
+    const r = '0x' + response.substring(0, 64)
+    const s = '0x' + response.substring(64, 128)
+
+    let v = parseInt(response.substring(128, 130), 16)
+
+    // fix ledger sign
+    if (v === 0 || v === 1) {
+      v = v + 27
+    }
+
+    return {
+      hex: concatSig(v, r, s),
+      v,
+      r,
+      s
+    }
   }
 }
-
-module.exports = { PermitSigner }
diff --git a/package.json b/package.json
index 20a129b..5aaf5e6 100644
--- a/package.json
+++ b/package.json
@@ -23,7 +23,6 @@
     "@apollo/client": "^3.3.20",
     "@metamask/onboarding": "^1.0.0",
     "@nuxtjs/moment": "^1.6.0",
-    "@ticket721/e712": "^0.4.1",
     "@walletconnect/web3-provider": "1.7.8",
     "ajv": "^6.10.2",
     "arraybuffer-loader": "^1.0.8",
diff --git a/store/torn.js b/store/torn.js
index c6dbee4..7f6b020 100644
--- a/store/torn.js
+++ b/store/torn.js
@@ -2,11 +2,11 @@
 import Web3 from 'web3'
 import { toBN } from 'web3-utils'
 import tornABI from '../abis/ERC20.abi.json'
+import PermitSigner from '../lib/Permit'
 
 import { isWalletRejection } from '@/utils'
 
 const { toWei, toHex, numberToHex } = require('web3-utils')
-const { PermitSigner } = require('../lib/Permit')
 
 const state = () => {
   return {
@@ -168,11 +168,11 @@ const actions = {
       }
 
       const permitSigner = new PermitSigner(domain, args)
-      const message = permitSigner.getPayload()
+      const req = permitSigner.getReqPayload()
 
       const callParams = {
         method: 'eth_signTypedData_v4',
-        params: [ethAccount, JSON.stringify(message)]
+        params: [ethAccount, JSON.stringify(req)]
       }
 
       dispatch(
@@ -186,18 +186,10 @@ const actions = {
         { root: true }
       )
 
-      let signature = await this.$provider.sendRequest(callParams)
-      signature = signature.substring(2)
-      const r = '0x' + signature.substring(0, 64)
-      const s = '0x' + signature.substring(64, 128)
-      let v = parseInt(signature.substring(128, 130), 16)
+      const query = await this.$provider.sendRequest(callParams)
+      const { v, r, s, hex } = permitSigner.getSignature(query)
 
-      // fix ledger sign
-      if (v === 0 || v === 1) {
-        v = v + 27
-      }
-
-      console.log('signature', v, r, s, signature)
+      console.log('signature', v, r, s, hex)
 
       // signature validation on contract
       await getters.tokenContract.methods
diff --git a/yarn.lock b/yarn.lock
index c3caa14..779643d 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2109,14 +2109,6 @@
   dependencies:
     defer-to-connect "^1.0.1"
 
-"@ticket721/e712@^0.4.1":
-  version "0.4.1"
-  resolved "https://registry.yarnpkg.com/@ticket721/e712/-/e712-0.4.1.tgz#b9be3f5d9d01a8468e0a49eeed67fe4454c87582"
-  integrity sha512-JHqyb2HntsmLJ4PtlXQ2AoU+s42X1itRtxeCAlA1AxOMORXQudbhly9wvGhN/Hbcl8VYpfgLJKp4hK3AT6xDiw==
-  dependencies:
-    bn.js "5.1.1"
-    ethers "4.0.41"
-
 "@types/anymatch@*":
   version "1.3.1"
   resolved "https://registry.yarnpkg.com/@types/anymatch/-/anymatch-1.3.1.tgz#336badc1beecb9dacc38bea2cf32adf627a8421a"
@@ -4060,11 +4052,6 @@ bn.js@4.11.8, bn.js@^4.0.0, bn.js@^4.1.0, bn.js@^4.1.1, bn.js@^4.4.0:
   resolved "https://registry.yarnpkg.com/bn.js/-/bn.js-4.11.8.tgz#2cde09eb5ee341f484746bb0309b3253b1b1442f"
   integrity sha512-ItfYfPLkWHUjckQCk8xC+LwxgK8NYcXywGigJgSwOP8Y2iyWT4f2vsZnoOXTTbo+o5yXmIUJ4gn5538SO5S3gA==
 
-bn.js@5.1.1:
-  version "5.1.1"
-  resolved "https://registry.yarnpkg.com/bn.js/-/bn.js-5.1.1.tgz#48efc4031a9c4041b9c99c6941d903463ab62eb5"
-  integrity sha512-IUTD/REb78Z2eodka1QZyyEk66pciRcP6Sroka0aI3tG/iwIdYLrBD62RsubR7vqdt3WyX8p4jxeatzmRSphtA==
-
 bn.js@^4.11.0, bn.js@^4.11.6, bn.js@^4.11.8, bn.js@^4.11.9:
   version "4.12.0"
   resolved "https://registry.yarnpkg.com/bn.js/-/bn.js-4.12.0.tgz#775b3f278efbb9718eec7361f483fb36fbbfea88"
@@ -6093,19 +6080,6 @@ electron-to-chromium@^1.4.84:
   resolved "https://registry.yarnpkg.com/electron-to-chromium/-/electron-to-chromium-1.4.86.tgz#90fe4a9787f48d6522957213408e08a8126b2ebc"
   integrity sha512-EVTZ+igi8x63pK4bPuA95PXIs2b2Cowi3WQwI9f9qManLiZJOD1Lash1J3W4TvvcUCcIR4o/rgi9o8UicXSO+w==
 
-elliptic@6.5.2:
-  version "6.5.2"
-  resolved "https://registry.yarnpkg.com/elliptic/-/elliptic-6.5.2.tgz#05c5678d7173c049d8ca433552224a495d0e3762"
-  integrity sha512-f4x70okzZbIQl/NSRLkI/+tteV/9WqL98zx+SQ69KbXxmVrmjwsNUPn/gYJJ0sHvEak24cZgHIPegRePAtA/xw==
-  dependencies:
-    bn.js "^4.4.0"
-    brorand "^1.0.1"
-    hash.js "^1.0.0"
-    hmac-drbg "^1.0.0"
-    inherits "^2.0.1"
-    minimalistic-assert "^1.0.0"
-    minimalistic-crypto-utils "^1.0.0"
-
 elliptic@6.5.4, elliptic@^6.4.0, elliptic@^6.5.2, elliptic@^6.5.4:
   version "6.5.4"
   resolved "https://registry.yarnpkg.com/elliptic/-/elliptic-6.5.4.tgz#da37cebd31e79a1367e941b592ed1fbebd58abbb"
@@ -6987,21 +6961,6 @@ ethereumjs-vm@^2.3.4:
     rustbn.js "~0.2.0"
     safe-buffer "^5.1.1"
 
-ethers@4.0.41:
-  version "4.0.41"
-  resolved "https://registry.yarnpkg.com/ethers/-/ethers-4.0.41.tgz#a0cff526f08c2e08c525cf82ef4483f6333b8000"
-  integrity sha512-QpW2CPZajquwiA7rVDozMksOuvdUBKIruamAakt0++EKBB/VWtLB9zSRZDInLDpp9fZYgOT/0trPD38r6CzLIg==
-  dependencies:
-    aes-js "3.0.0"
-    bn.js "^4.4.0"
-    elliptic "6.5.2"
-    hash.js "1.1.3"
-    js-sha3 "0.5.7"
-    scrypt-js "2.0.4"
-    setimmediate "1.0.4"
-    uuid "2.0.1"
-    xmlhttprequest "1.8.0"
-
 ethers@^5.5.1:
   version "5.6.1"
   resolved "https://registry.yarnpkg.com/ethers/-/ethers-5.6.1.tgz#a56cd67f1595b745dc3dde0ccf2b5de53a41a6d0"
@@ -8306,14 +8265,6 @@ hash-sum@^2.0.0:
   resolved "https://registry.yarnpkg.com/hash-sum/-/hash-sum-2.0.0.tgz#81d01bb5de8ea4a214ad5d6ead1b523460b0b45a"
   integrity sha512-WdZTbAByD+pHfl/g9QSsBIIwy8IT+EsPiKDs0KNX+zSHhdDLFKdZu0BQHljvO+0QI/BasbMSUa8wYNCZTvhslg==
 
-hash.js@1.1.3:
-  version "1.1.3"
-  resolved "https://registry.yarnpkg.com/hash.js/-/hash.js-1.1.3.tgz#340dedbe6290187151c1ea1d777a3448935df846"
-  integrity sha512-/UETyP0W22QILqS+6HowevwhEFJ3MBJnwTf75Qob9Wz9t0DPuisL8kW8YZMK62dHAKE1c1p+gY1TtOLY+USEHA==
-  dependencies:
-    inherits "^2.0.3"
-    minimalistic-assert "^1.0.0"
-
 hash.js@1.1.7, hash.js@^1.0.0, hash.js@^1.0.3, hash.js@^1.1.7:
   version "1.1.7"
   resolved "https://registry.yarnpkg.com/hash.js/-/hash.js-1.1.7.tgz#0babca538e8d4ee4a0f8988d68866537a003cf42"
@@ -9733,16 +9684,16 @@ js-beautify@^1.6.14:
     mkdirp "~0.5.1"
     nopt "~4.0.1"
 
-js-sha3@0.5.7, js-sha3@^0.5.7:
-  version "0.5.7"
-  resolved "https://registry.yarnpkg.com/js-sha3/-/js-sha3-0.5.7.tgz#0d4ffd8002d5333aabaf4a23eed2f6374c9f28e7"
-  integrity sha1-DU/9gALVMzqrr0oj7tL2N0yfKOc=
-
 js-sha3@0.8.0, js-sha3@^0.8.0:
   version "0.8.0"
   resolved "https://registry.yarnpkg.com/js-sha3/-/js-sha3-0.8.0.tgz#b9b7a5da73afad7dedd0f8c463954cbde6818840"
   integrity sha512-gF1cRrHhIzNfToc802P800N8PpXS+evLLXfsVpowqmAFR9uwbi89WvXg2QspOmXL8QL86J4T1EpFu+yUkwJY3Q==
 
+js-sha3@^0.5.7:
+  version "0.5.7"
+  resolved "https://registry.yarnpkg.com/js-sha3/-/js-sha3-0.5.7.tgz#0d4ffd8002d5333aabaf4a23eed2f6374c9f28e7"
+  integrity sha1-DU/9gALVMzqrr0oj7tL2N0yfKOc=
+
 "js-tokens@^3.0.0 || ^4.0.0", js-tokens@^4.0.0:
   version "4.0.0"
   resolved "https://registry.yarnpkg.com/js-tokens/-/js-tokens-4.0.0.tgz#19203fb59991df98e3a287050d4647cdeaf32499"
@@ -13826,11 +13777,6 @@ schema-utils@^3.0.0:
     ajv "^6.12.5"
     ajv-keywords "^3.5.2"
 
-scrypt-js@2.0.4:
-  version "2.0.4"
-  resolved "https://registry.yarnpkg.com/scrypt-js/-/scrypt-js-2.0.4.tgz#32f8c5149f0797672e551c07e230f834b6af5f16"
-  integrity sha512-4KsaGcPnuhtCZQCxFxN3GVYIhKFPTdLd8PLC552XwbMndtD0cjRFAhDuuydXQ0h08ZfPgzqe6EKHozpuH74iDw==
-
 scrypt-js@3.0.1, scrypt-js@^3.0.0, scrypt-js@^3.0.1:
   version "3.0.1"
   resolved "https://registry.yarnpkg.com/scrypt-js/-/scrypt-js-3.0.1.tgz#d314a57c2aef69d1ad98a138a21fe9eafa9ee312"
@@ -14016,11 +13962,6 @@ set-value@^2.0.0, set-value@^2.0.1:
     is-plain-object "^2.0.3"
     split-string "^3.0.1"
 
-setimmediate@1.0.4:
-  version "1.0.4"
-  resolved "https://registry.yarnpkg.com/setimmediate/-/setimmediate-1.0.4.tgz#20e81de622d4a02588ce0c8da8973cbcf1d3138f"
-  integrity sha1-IOgd5iLUoCWIzgyNqJc8vPHTE48=
-
 setimmediate@^1.0.4, setimmediate@^1.0.5:
   version "1.0.5"
   resolved "https://registry.yarnpkg.com/setimmediate/-/setimmediate-1.0.5.tgz#290cbb232e306942d7d7ea9b83732ab7856f8285"
@@ -15408,11 +15349,6 @@ utils-merge@1.0.1:
   resolved "https://registry.yarnpkg.com/utils-merge/-/utils-merge-1.0.1.tgz#9f95710f50a267947b2ccc124741c1028427e713"
   integrity sha1-n5VxD1CiZ5R7LMwSR0HBAoQn5xM=
 
-uuid@2.0.1:
-  version "2.0.1"
-  resolved "https://registry.yarnpkg.com/uuid/-/uuid-2.0.1.tgz#c2a30dedb3e535d72ccf82e343941a50ba8533ac"
-  integrity sha1-wqMN7bPlNdcsz4LjQ5QaULqFM6w=
-
 uuid@3.3.2:
   version "3.3.2"
   resolved "https://registry.yarnpkg.com/uuid/-/uuid-3.3.2.tgz#1b4af4955eb3077c501c23872fc6513811587131"
@@ -16589,11 +16525,6 @@ xmldom@^0.1.22:
   resolved "https://registry.yarnpkg.com/xmldom/-/xmldom-0.1.31.tgz#b76c9a1bd9f0a9737e5a72dc37231cf38375e2ff"
   integrity sha512-yS2uJflVQs6n+CyjHoaBmVSqIDevTAWrzMmjG1Gc7h1qQ7uVozNhEPJAwZXWyGQ/Gafo3fCwrcaokezLPupVyQ==
 
-xmlhttprequest@1.8.0:
-  version "1.8.0"
-  resolved "https://registry.yarnpkg.com/xmlhttprequest/-/xmlhttprequest-1.8.0.tgz#67fe075c5c24fef39f9d65f5f7b7fe75171968fc"
-  integrity sha1-Z/4HXFwk/vOfnWX197f+dRcZaPw=
-
 xtend@^4.0.0, xtend@^4.0.1, xtend@~4.0.0, xtend@~4.0.1:
   version "4.0.2"
   resolved "https://registry.yarnpkg.com/xtend/-/xtend-4.0.2.tgz#bb72779f5fa465186b1f438f674fa347fdb5db54"