Don't kill 1/2 bytes from private keys please

[mirek]

When using:

web3.eth.accounts.signTransaction(txParams, privateKey)

a) If your private key is hex0x - all good.

b) If your private key is hex - everyting will work fine, no errors, but your signed transaction will be with private key with one byte zero'ed.

c) If your private key is Buffer - everything will be signed, no errors, but your signed transaction will be with private key with two first bytes zero'ed.

a) 870c20575bd9da9d747011401ed345edf6229c96ba2bfcd965ed6dee1fc3afd3
b) 000c20575bd9da9d747011401ed345edf6229c96ba2bfcd965ed6dee1fc3afd3
c) 000020575bd9da9d747011401ed345edf6229c96ba2bfcd965ed6dee1fc3afd3

...which is kind of cute that 3 different representations create 3 valid, different signed transactions, all thanks to web3 not validating it's inputs and this internally doing the same https://github.com/MaiaVictor/eth-lib/blob/master/src/account.js#L47

const Web3 = require('web3')
const web3 = new Web3('http://localhost:8545')

const pk = '870c20575bd9da9d747011401ed345edf6229c96ba2bfcd965ed6dee1fc3afd3'
const pk0x = `0x${pk}`
const pkb = Buffer.from(pk, 'hex')

const tx = {
  to: '0xF0109fC8DF283027b6285cc889F5aA624EaC1F55',
  value: '1000000000',
  gas: 2000000
}

const mh = _1 => web3.eth.accounts.signTransaction(tx, _1).then(_2 => _2.rawTransaction)

async function main() {
  console.log('pk     ', await mh(pk))
  console.log('pk0x   ', await mh(pk0x))
  console.log('pkb    ', await mh(pkb))

  console.log('pk00   ', await mh('0x00' + pk.slice(2)))
  console.log('pk0000 ', await mh('0x0000' + pk.slice(4)))
}

main()

// Output:
// pk      0xf8648080831e848094f0109fc8df283027b6285cc889f5aa624eac1f55843b9aca00802ba0ef96e99731c7aafd230a21c322e4043a830a5174370d7395f69c3c97dc22540da03262a83de0b19a3afb97c9ce42c3be8f07291023120227420a2850ec1452a0f9
// pk0x    0xf8648080831e848094f0109fc8df283027b6285cc889f5aa624eac1f55843b9aca00802ba0c7f6b9dd95dfbd7b433b63b0862381fe87c8515cc2c1ee2b605639aafe49a076a02ac4429dcd696c485f88dfe9809a75939890e1b8e260132eeb671c5a464630e3
// pkb     0xf8648080831e848094f0109fc8df283027b6285cc889f5aa624eac1f55843b9aca00802ca0b30df73f90272f0819e103bcfcb1b7b1d960f329f0ad6a37df406a9f569d9e25a013569cca9c23e5050e0f4c0957edad761aba727d802769aaa9028ed1a5232171
// pk00    0xf8648080831e848094f0109fc8df283027b6285cc889f5aa624eac1f55843b9aca00802ba0ef96e99731c7aafd230a21c322e4043a830a5174370d7395f69c3c97dc22540da03262a83de0b19a3afb97c9ce42c3be8f07291023120227420a2850ec1452a0f9
// pk0000  0xf8648080831e848094f0109fc8df283027b6285cc889f5aa624eac1f55843b9aca00802ca0b30df73f90272f0819e103bcfcb1b7b1d960f329f0ad6a37df406a9f569d9e25a013569cca9c23e5050e0f4c0957edad761aba727d802769aaa9028ed1a5232171