anchor.diff:          keyTextArea.value = bytesToHexString(cipher.key.toList());
         });
         streamDecrypt = decryptButton.onClick.listen((e) {
  -        int dim = sqrt((keyTextArea.value.length/2).floor()).floor();
  -        if (keyTextArea.value.length % 2 != 0 || (keyTextArea.value.length/2).floor() > pow(dim, 2)) {
  +        int dim = sqrt((keyTextArea.value.length / 2).floor()).floor();
  +        if (keyTextArea.value.length % 2 != 0 ||
  +            (keyTextArea.value.length / 2).floor() > pow(dim, 2)) {
             toast('Incorrect key length!');
             cipher.key = null;
             return;
  
positive.code:           validator: nodeValidator);
        HillCipher cipher = new HillCipher(256);
        streamKeyChange = keyTextArea.onChange.listen((e) {
          int dim = sqrt((keyTextArea.value.length/2).floor()).floor();
          if (keyTextArea.value.length % 2 != 0 || (keyTextArea.value.length/2).floor() > pow(dim, 2)) {
            toast('Incorrect key length!');
            cipher.key = null;
            return;
  
negative.code:         cipher.setKey(hexStringToBytes(keyTextArea.value));
        });
        streamEncrypt = encryptButton.onClick.listen((e) {
          int dim = sqrt((keyTextArea.value.length / 2).floor()).floor();
          if (keyTextArea.value.length % 2 != 0 ||
              (keyTextArea.value.length / 2).floor() > pow(dim, 2)) {
            toast('Incorrect key length!');
            cipher.key = null;
            return;
  