tmp-encrypt

package.json

@@ -25,6 +25,7 @@
     "circom_runtime": "^0.1.13",
     "circomlib": "git+https://github.com/tornadocash/circomlib.git#d20d53411d1bef61f38c99a8b36d5d0cc4836aa1",
     "dotenv": "^10.0.0",
+    "eth-sig-util": "^3.0.1",
     "ethereum-waffle": "^3.2.0",
     "ethers": "^5.0.0",
     "ffiasm": "^0.1.3",

src/index.js

@@ -47,6 +47,8 @@ async function getProof({ inputs, outputs, tree, extAmount, fee, recipient, rela
   const outputIndex = tree.elements().length - 1
   const outputPath = tree.path(outputIndex).pathElements
 
+  //encrypt(encryptedPublicKey, { data }, 'x25519-xsalsa20-poly1305')
+
   const extData = {
     recipient: toFixedHex(recipient, 20),
     relayer: toFixedHex(relayer, 20),

src/kaypair.js

@@ -1,31 +0,0 @@
-const { ethers } = require('hardhat')
-const { BigNumber } = ethers
-const { randomBN, poseidonHash, toFixedHex } = require('./utils')
-
-class Keypair {
-  constructor(privkey = randomBN()) {
-    this.privkey = privkey
-    this.pubkey = poseidonHash([this.privkey])
-    this.encryptionKey = 0 // todo
-  }
-
-  toString() {
-    return toFixedHex(this.pubkey) + toFixedHex(this.encryptionKey).slice(2)
-  }
-
-  static fromString(str) {
-    if (str.length === 130) {
-      str = str.slice(2)
-    }
-    if (str.length !== 128) {
-      throw new Error('Invalid key length')
-    }
-    return Object.assign(new Keypair(), {
-      privkey: null,
-      pubkey: BigNumber.from('0x' + str.slice(0, 64)),
-      encryptionKey: BigNumber.from('0x' + str.slice(64, 128)),
-    })
-  }
-}
-
-module.exports = Keypair

src/keypair.js

@@ -0,0 +1,54 @@
+const { encrypt, decrypt, getEncryptionPublicKey } = require('eth-sig-util')
+const { ethers } = require('hardhat')
+const { BigNumber } = ethers
+const { randomBN, poseidonHash, toFixedHex } = require('./utils')
+
+class Keypair {
+  constructor(privkey = ethers.Wallet.createRandom().privateKey) {
+    this.privkey = privkey
+    console.log(privkey)
+    this.pubkey = poseidonHash([this.privkey])
+    this.encryptionKey = getEncryptionPublicKey(privkey.slice(2))
+    console.log('enc key', this.encryptionKey)
+  }
+
+  toString() {
+    return toFixedHex(this.pubkey) + toFixedHex(this.encryptionKey).slice(2)
+  }
+
+  static fromString(str) {
+    if (str.length === 130) {
+      str = str.slice(2)
+    }
+    if (str.length !== 128) {
+      throw new Error('Invalid key length')
+    }
+    return Object.assign(new Keypair(), {
+      privkey: null,
+      pubkey: BigNumber.from('0x' + str.slice(0, 64)),
+      encryptionKey: BigNumber.from('0x' + str.slice(64, 128)),
+    })
+  }
+
+  encrypt({ blinding, amount }) {
+    console.log(BigNumber.from(blinding).toHexString())
+    const bytes = Buffer.concat([
+      Buffer.from(BigNumber.from(blinding).toHexString(), 0, 31),
+      Buffer.from(BigNumber.from(amount).toHexString(), 0, 31),
+    ])
+    console.log(bytes)
+    return encrypt(this.encryptionKey, { data: bytes.toString('base64') }, 'x25519-xsalsa20-poly1305')
+  }
+
+  decrypt(data) {
+    const decryptedMessage = decrypt(data, this.privkey.slice(2))
+    const buf = Buffer.from(decryptedMessage, 'base64')
+    console.log(buf)
+    return {
+      blinding: BigNumber.from('0x' + buf.slice(0, 31).toString('hex')),
+      amount: BigNumber.from('0x' + buf.slice(31, 62).toString('hex')),
+    }
+  }
+}
+
+module.exports = Keypair

src/utils.js

@@ -55,6 +55,36 @@ async function revertSnapshot(id) {
   await ethers.provider.send('evm_revert', [id])
 }
 
+function packEncryptedMessage(encryptedMessage) {
+  const nonceBuf = Buffer.from(encryptedMessage.nonce, 'base64')
+  const ephemPublicKeyBuf = Buffer.from(encryptedMessage.ephemPublicKey, 'base64')
+  const ciphertextBuf = Buffer.from(encryptedMessage.ciphertext, 'base64')
+  const messageBuff = Buffer.concat([
+    Buffer.alloc(24 - nonceBuf.length),
+    nonceBuf,
+    Buffer.alloc(32 - ephemPublicKeyBuf.length),
+    ephemPublicKeyBuf,
+    ciphertextBuf,
+  ])
+  return '0x' + messageBuff.toString('hex')
+}
+
+function unpackEncryptedMessage(encryptedMessage) {
+  if (encryptedMessage.slice(0, 2) === '0x') {
+    encryptedMessage = encryptedMessage.slice(2)
+  }
+  const messageBuff = Buffer.from(encryptedMessage, 'hex')
+  const nonceBuf = messageBuff.slice(0, 24)
+  const ephemPublicKeyBuf = messageBuff.slice(24, 56)
+  const ciphertextBuf = messageBuff.slice(56)
+  return {
+    version: 'x25519-xsalsa20-poly1305',
+    nonce: nonceBuf.toString('base64'),
+    ephemPublicKey: ephemPublicKeyBuf.toString('base64'),
+    ciphertext: ciphertextBuf.toString('base64'),
+  }
+}
+
 module.exports = {
   FIELD_SIZE,
   randomBN,
@@ -65,4 +95,6 @@ module.exports = {
   getExtDataHash,
   takeSnapshot,
   revertSnapshot,
+  packEncryptedMessage,
+  unpackEncryptedMessage,
 }

src/utxo.js

@@ -1,7 +1,7 @@
 const { ethers } = require('hardhat')
 const { BigNumber } = ethers
 const { randomBN, poseidonHash } = require('./utils')
-const Keypair = require('./kaypair')
+const Keypair = require('./keypair')
 
 class Utxo {
   constructor({ amount = 0, keypair = new Keypair(), blinding = randomBN(), index } = {}) {

test/full.test.js

@@ -8,6 +8,22 @@ const MERKLE_TREE_HEIGHT = 5
 const MerkleTree = require('fixed-merkle-tree')
 
 const { deposit, transact, withdraw, merge } = require('../src/index')
+const Keypair = require('../src/keypair')
+
+describe.only('Keypair', () => {
+  it('should work', () => {
+    const blinding = 3
+    const amount = 5
+    const keypair = new Keypair()
+
+    const cyphertext = keypair.encrypt({ blinding, amount})
+    console.log(cyphertext)
+    const result = keypair.decrypt(cyphertext)
+    console.log(result, result.blinding.toString())
+    expect(result.blinding).to.be.equal(blinding)
+    expect(result.amount).to.be.equal(amount)
+  })
+})
 
 describe('TornadoPool', () => {
   let snapshotId, tornadoPool

yarn.lock

@@ -3226,6 +3226,16 @@ eth-sig-util@^2.5.2:
     tweetnacl "^1.0.3"
     tweetnacl-util "^0.15.0"
 
+eth-sig-util@^3.0.1:
+  version "3.0.1"
+  resolved "https://registry.yarnpkg.com/eth-sig-util/-/eth-sig-util-3.0.1.tgz#8753297c83a3f58346bd13547b59c4b2cd110c96"
+  integrity sha512-0Us50HiGGvZgjtWTyAI/+qTzYPMLy5Q451D0Xy68bxq1QMWdoOddDwGvsqcFT27uohKgalM9z/yxplyt+mY2iQ==
+  dependencies:
+    ethereumjs-abi "^0.6.8"
+    ethereumjs-util "^5.1.1"
+    tweetnacl "^1.0.3"
+    tweetnacl-util "^0.15.0"
+
 eth-tx-summary@^3.1.2:
   version "3.2.4"
   resolved "https://registry.yarnpkg.com/eth-tx-summary/-/eth-tx-summary-3.2.4.tgz#e10eb95eb57cdfe549bf29f97f1e4f1db679035c"