Basic Password Lock System

#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <Keypad.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

const byte ROWS = 4;
const byte COLS = 4;

char keys[ROWS][COLS] =
{
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};

byte rowPins[ROWS] = {9,8,7,6};
byte colPins[COLS] = {5,4,3,2};

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

String password = "1234";
String enteredPassword = "";

const int greenLED = 10;
const int redLED = 11;

void setup()
{
  pinMode(greenLED, OUTPUT);
  pinMode(redLED, OUTPUT);

  lcd.init();
  lcd.backlight();

  lcd.setCursor(0,0);
  lcd.print("Enter Password");
}

void loop()
{
  char key = keypad.getKey();

  if(key)
  {
    lcd.setCursor(enteredPassword.length(),1);
    lcd.print("*");

    enteredPassword += key;

    if(enteredPassword.length() == 4)
    {
      lcd.clear();

      if(enteredPassword == password)
      {
        lcd.print("Access Granted");

        digitalWrite(greenLED, HIGH);
        delay(3000);
        digitalWrite(greenLED, LOW);
      }
      else
      {
        lcd.print("Access Denied");

        digitalWrite(redLED, HIGH);
        delay(3000);
        digitalWrite(redLED, LOW);
      }

      enteredPassword = "";

      lcd.clear();
      lcd.print("Enter Password");
    }
  }
}