Certificates can be used to secure your DNN-site. Certificates are no rocket science, but before you start using them it is important to understand a few concepts. In this presentation, you will learn everything you need to know. Using easy-to-understand examples it will be shown exactly how certificates work and also why it is so necessary to use them. And although we will discuss some math, the presentation does not require any prior knowledge: it will be just fun-damental.