How to get sender’s Ethereum address and public key from signed transaction

ethers.js version of the article below:

https://piyopiyo.medium.com/how-to-get-senders-ethereum-address-and-public-key-from-signed-transaction-44abe17a1791

In this article, I’d like to explain how to get Ethereum address and public key of sender (who signs to transaction) from signed transaction.

Example of signed transaction

Below is an actual signed transaction which has been sent to Ropsten network: https://ropsten.etherscan.io/tx/0xf4727b35f10cbe2256b38adcc594f25854a7f16c8461e280079e7003a18d446d

code:signedTx

0xf86b808504a817c800825208942890228d4478e2c3b0ebf5a38479e3396c1d6074872386f26fc100008029a0520e5053c1b573d747f823a0b23d52e5a619298f46cd781d677d0e5e78fbc750a075be461137c2c2a5594beff76ecb11a215384c574a7e5b620dba5cc63b0a0f13

Retrieve sender’s Ethereum address and public key

code:js

(async () => {

const ethers = require('ethers')

const CHIAN_ID = 3 // Ropsten

const SIGNED_TX = '0xf86b808504a817c800825208942890228d4478e2c3b0ebf5a38479e3396c1d6074872386f26fc100008029a0520e5053c1b573d747f823a0b23d52e5a619298f46cd781d677d0e5e78fbc750a075be461137c2c2a5594beff76ecb11a215384c574a7e5b620dba5cc63b0a0f13'

const tx = ethers.utils.RLP.decode(ethers.utils.arrayify(SIGNED_TX))

const v = ethers.BigNumber.from(tx6).toNumber()

const r = ethers.utils.hexZeroPad(tx7, 32)

const s = ethers.utils.hexZeroPad(tx8, 32)

const rawTx = tx.slice(0, 6)

// EIP-155

if (CHIAN_ID !== 0) {

rawTx.push(ethers.utils.hexlify(CHIAN_ID))

rawTx.push('0x')

}

const digest = ethers.utils.keccak256(ethers.utils.RLP.encode(rawTx))

const signature = ethers.utils.joinSignature({v, r, s});