 So today we're going to talk about input validation, data validation. What does your application do with the data that's inputted into it? Now this is quite... Boring! It's boring. Before this week I'm more interesting, let's go! Input validation! Helps keep your application secure. There are two ways to do this. You can blacklisting. List or think things which you're not allowed. Shook in your shampoo and your tummy. Listing. Which is a list of things that you are allowed. Do this and you'll be more secure. Check the description for more information. Don't forget to like my video. Stay secure my friends.