File system security
Files are where we store things. Those things might not be for everybody to see. Sometimes, we must hide data or ensure that only programs that we trust can access it. OSs can help. Every OS has a way of handling access to files and directories. You can generally allow or disallow read- or write access to them.
However, what happens when you want to share files? Let us assume that you want to transfer data over a wire or store it on another drive such as a removable USB drive. In that case, ensuring that level of security is quite challenging. This means that you might have to encrypt data to prevent it from being abused.
Security – a topic of its own
I am only covering the basics of security and encryption here. This is not a complete guide to this complicated and extensive topic. There have been hundreds of books written on this topic alone. I want you to know that you can do security and encryption. However, if you want to take this seriously...