It's very important to secure your login system which can be attacked by various attacking methode. SQL Injection is the common attacking methode that is used to gain the login authetication of the login system.

One of the most common SQL Injection look like this:

' or '1'='1' --

It's very unsecured to use the simple login verification methode to login in your system while currently most online web login system use the more secured way of login.

This tutorial will help to secure your login sytem by just implementing the mysqli_prepare to your login function.