tornado-nova/src/utils.js

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/* global network */
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const crypto = require('crypto')
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const { ethers } = require('hardhat')
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const BigNumber = ethers.BigNumber
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const { poseidon } = require('circomlib')
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const poseidonHash = (items) => BigNumber.from(poseidon(items).toString())
const poseidonHash2 = (a, b) => poseidonHash([a, b])
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const FIELD_SIZE = BigNumber.from(
'21888242871839275222246405745257275088548364400416034343698204186575808495617',
)
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/** Generate random number of specified byte length */
const randomBN = (nbytes = 31) => BigNumber.from(crypto.randomBytes(nbytes))
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function getExtDataHash({
recipient,
extAmount,
relayer,
fee,
encryptedOutput1,
encryptedOutput2,
isL1Withdrawal,
}) {
const abi = new ethers.utils.AbiCoder()
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const encodedData = abi.encode(
[
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'tuple(address recipient,int256 extAmount,address relayer,uint256 fee,bytes encryptedOutput1,bytes encryptedOutput2,bool isL1Withdrawal)',
],
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[
{
recipient: toFixedHex(recipient, 20),
extAmount: toFixedHex(extAmount),
relayer: toFixedHex(relayer, 20),
fee: toFixedHex(fee),
encryptedOutput1: encryptedOutput1,
encryptedOutput2: encryptedOutput2,
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isL1Withdrawal: isL1Withdrawal,
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},
],
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)
const hash = ethers.utils.keccak256(encodedData)
return BigNumber.from(hash).mod(FIELD_SIZE)
}
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/** BigNumber to hex string of specified length */
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function toFixedHex(number, length = 32) {
let result =
'0x' +
(number instanceof Buffer
? number.toString('hex')
: BigNumber.from(number).toHexString().replace('0x', '')
).padStart(length * 2, '0')
if (result.indexOf('-') > -1) {
result = '-' + result.replace('-', '')
}
return result
}
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/** Convert value into buffer of specified byte length */
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const toBuffer = (value, length) =>
Buffer.from(
BigNumber.from(value)
.toHexString()
.slice(2)
.padStart(length * 2, '0'),
'hex',
)
function shuffle(array) {
let currentIndex = array.length
let randomIndex
// While there remain elements to shuffle...
while (0 !== currentIndex) {
// Pick a remaining element...
randomIndex = Math.floor(Math.random() * currentIndex)
currentIndex--
// And swap it with the current element.
;[array[currentIndex], array[randomIndex]] = [array[randomIndex], array[currentIndex]]
}
return array
}
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async function getSignerFromAddress(address) {
await network.provider.request({
method: 'hardhat_impersonateAccount',
params: [address],
})
return await ethers.provider.getSigner(address)
}
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module.exports = {
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FIELD_SIZE,
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randomBN,
toFixedHex,
toBuffer,
poseidonHash,
poseidonHash2,
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getExtDataHash,
shuffle,
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getSignerFromAddress,
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}