/******************************************************
 Find and retrieve the encryption key automatically
 Note: This is a draft version, please help to modify, Thanks!
 ******************************************************/
function keyFinder (str) { // str is used to get the input of encrypted string
  const wordBank = [
    'I ',
    'You ',
    'We ',
    'They ',
    'He ',
    'She ',
    'It ',
    ' the ',
    'The ',
    ' of ',
    ' is ',
    'Is ',
    ' am ',
    'Am ',
    ' are ',
    'Are ',
    ' have ',
    'Have ',
    ' has ',
    'Has ',
    ' may ',
    'May ',
    ' be ',
    'Be ']
  // let wordbankelementCounter = 0;
  // let key = 0; // return zero means the key can not be found
  const inStr = str.toString() // convert the input to String
  let outStr = '' // store the output value
  let outStrElement = '' // temporary store the word inside the outStr, it is used for comparison
  for (let k = 0; k < 26; k++) { // try the number of key shifted, the sum of character from a-z or A-Z is 26
    outStr = caesarCipherEncodeAndDecodeEngine(inStr, k) // use the encryption engine to decrypt the input string

    // loop through the whole input string
    for (let s = 0; s < outStr.length; s++) {
      for (let i = 0; i < wordBank.length; i++) {
        // initialize the outStrElement wh