encrypt method

String encrypt(String clearText, { int saltLength = 4, CharClass charClass = CharClass.chars95, String charSetMembers = '', })

Encrypts the clearText with a randomly generated salt of the length saltLength. see decrypt() for reverse encryption.

Implementation

String encrypt(String clearText,
    {int saltLength = 4,
    CharClass charClass = CharClass.chars95,
    String charSetMembers = ''}) {
  if (charSetMembers.isEmpty) {
    charSetMembers = BaseRandom.getCharClassMembers(charClass) ?? '';
  }
  var rc = saltLength == 0 ? '' : trueRandom.nextString(saltLength);
  final currentState = firstState.toList();
  currentState[0] =
      random.maskOperand(random.maskOperand(rc.hashCode) + currentState[0]);
  random.restoreState(currentState);
  if (charClass == CharClass.chars95 || charClass == CharClass.chars96) {
    // the charset is ordered like ASCII: we can calculate the index
    final upperBound = charClass == CharClass.chars95 ? 127 : 128;
    final max = charClass == CharClass.chars95 ? 95 : 96;
    for (var ix = 0; ix < clearText.length; ix++) {
      final code = clearText.codeUnitAt(ix);
      if (code < 32 || code >= upperBound) {
        rc += clearText[ix];
      } else {
        final rand = random.nextInt(max: max);
        final value = 32 + ((code - 32 + rand) % max);
        rc += String.fromCharCode(value);
      }
    }
  } else {
    // the charset is not ordered like ASCII: we must search the index
    final max = charClass == CharClass.chars95 ? 95 : 96;
    for (var ix = 0; ix < clearText.length; ix++) {
      final index = charSetMembers.indexOf(clearText[ix]);
      if (index < 0) {
        rc += clearText[ix];
      } else {
        final rand = random.nextInt(max: max);
        final value = (index + rand) % max;
        rc += charSetMembers[value];
      }
    }
  }
  return rc;
}