address from pkey

eckey.js

// from https://etherworld.co/2017/11/17/understanding-the-concept-of-private-key-public-key-and-address-in-ethereum-blockchain/

const EC = require('elliptic').ec
const BN = require('bn.js')
const ec = new EC('secp256k1')
const keccak256 = require('js-sha3').keccak256

const G = ec.g
const privateKey = process.argv[2]
const pk = new BN(privateKey)
const pub = G.mul(pk)

const x = pub.getX().toBuffer()
const y = pub.getY().toBuffer()
const key = Buffer.concat([x, y])

console.log(key.toString('hex'))

const address = keccak256(key)
const buf = Buffer.from(address, 'hex')

console.log('0x' + buf.slice(-20).toString('hex'))