AES Arduino

byte aes_key[] = {0xA6, 0x39, 0x6, 0xE0, 0x35, 0x8C, 0x18, 0x7D, 0xDC, 0xF5, 0xB8, 0x2D, 0xA5, 0x83, 0x76, 0x46, 0xF0, 0x28, 0xF3, 0x988};

byte aes_iv[] = {0x48, 0x6C, 0x69, 0xCA, 0x8F, 0x66, 0xAF, 0x1B, 0xAD, 0x30, 0x1B, 0xE6, 0x51, 0xEA, 0x08, 0x89, 0xE4, 0xF4, 0x71, 0xCF, 0x00, 0xC5, 0xDC, 0x3C, 0x33, 0x0B, 0xCE, 0xD7, 0x6A, 0x8C, 0x97, 0xCF};

void aes_init() {
  aesLib.gen_iv(aes_iv);
  aesLib.set_paddingmode((paddingMode)0);
}

String encrypt(char * msg, byte iv[]) {
  unsigned long ms = micros();
  int msgLen = strlen(msg);
  char encrypted[2 * msgLen];
  aesLib.encrypt64(msg, msgLen, encrypted, aes_key, sizeof(aes_key), iv);
  //  Serial.print("Encryption took: ");
  //  Serial.print(micros() - ms);
  //  Serial.println("us");
  return String(encrypted);
}

String decrypt(char * msg, byte iv[]) {
  unsigned long ms = micros();
  int msgLen = strlen(msg);
  char decrypted[msgLen]; // half may be enough
  aesLib.decrypt64(msg, msgLen, decrypted, aes_key, sizeof(aes_key), iv);
  //  Serial.print("Decryption [2] took: ");
  //  Serial.print(micros() - ms);
  //  Serial.println("us");
  return String(decrypted);
}

void setup() {
    aes_init();
  String encrypted = encrypt((const char*)"Rian Pratama", aes_iv);
  String decrypted = decrypt((char*)encrypted.c_str(), aes_iv);
  Serial.print("Encrypt: ");
  Serial.println(encrypted);
  Serial.print("Decrypt: ");
  Serial.println(decrypted);

  String plain = encrypted;

  // decryped may contain mess if not properly padded
  if (decrypted.indexOf(plain) == -1) {
    Serial.println("Decryption FAILED!");
    Serial.print("At:");
    Serial.println(plain.indexOf(decrypted));
    delay(5000);
  } else {
    if (plain.length() == decrypted.length()) {
      Serial.println("Decryption successful.");
    } else {
      Serial.print("Decryption length incorrect. Plain: ");
      Serial.print(plain.length());
      Serial.print(" dec: ");
      Serial.println(decrypted.length());
    }
  }
}

void loop(){}