signAndVerifyMsg.ts

import { 
  Avalanche,
  Buffer,
  BinTools
} from "../../src"
import {
  AVMAPI, 
  KeyChain,
  KeyPair
} from "../../src/apis/avm"
import { getPreferredHRP } from "../../src/utils"
import { 
  PrivateKeyPrefix, 
  DefaultLocalGenesisPrivateKey
} from "../../src/utils"
import createHash from 'create-hash';
    
const ip: string = "localhost"
const port: number = 9650
const protocol: string = "http"
const networkID: number = 12345
const avalanche: Avalanche = new Avalanche(ip, port, protocol, networkID)
const xchain: AVMAPI = avalanche.XChain()
const xKeychain: KeyChain = xchain.keyChain()
const privKey: string = `${PrivateKeyPrefix}${DefaultLocalGenesisPrivateKey}`
xKeychain.importKey(privKey)
const xAddresses: Buffer[] = xchain.keyChain().getAddresses()
const xAddressStrings: string[] = xchain.keyChain().getAddressStrings()
const bintools = BinTools.getInstance();
const key: KeyPair = xKeychain.getKey(xAddresses[0])

const digestMessage = (msgStr: string) => {
  const mBuf: Buffer = Buffer.from(msgStr, 'utf8')
  const msgSize: Buffer = Buffer.alloc(4)
  msgSize.writeUInt32BE(mBuf.length, 0)
  const msgBuf: Buffer = Buffer.from(`\x1AAvalanche Signed Message:\n${msgSize}${msgStr}`, 'utf8')
  return createHash('sha256').update(msgBuf).digest()
}

const recover = (msgStr: string, signature: Buffer): string => {
  let digest: globalThis.Buffer = digestMessage(msgStr)
  let digestBuff: Buffer = Buffer.from(digest.toString('hex'), 'hex')
  let hrp: string = getPreferredHRP(networkID)
  let keypair: KeyPair = new KeyPair(hrp, 'X')

  let pubKey: Buffer = keypair.recover(digestBuff, signature)
  let addressBuff: Buffer = keypair.addressFromPublicKey(pubKey)
  let address: string = bintools.addressToString(hrp, 'X', addressBuff)
  return address
}
      
const main = async (): Promise<any> => {
  console.log(`Address: ${xAddressStrings[0]}`)
  const msgStr: string = "From snowflake to Avalanche"
  console.log(`Message: ${msgStr}`)
  const digest: globalThis.Buffer = digestMessage(msgStr)
  const digestHex = digest.toString('hex')
  const digestBuff: Buffer = Buffer.from(digestHex, 'hex')
  const signed: Buffer = key.sign(digestBuff)
  console.log(`Signature: ${bintools.cb58Encode(signed)}`)
  console.log("--------------------------")
  console.log("Recovering address from message and signature...")
  const recoveredAddress: string = recover(msgStr, signed)
  console.log(`Address: ${recoveredAddress}`)
}
    
main()