N is for …


This is an often used phrase, but what exactly is a network? In its simplest form, it is several computers connected to each other. In a single building, these would typically form a Local Area Network (LAN), or if several offices are connected together these would be called a Wide Area Network (WAN).There are several different network components, such as routers, switches and firewalls. These will be explained in the relevant posts on this site.


Non-repudiation means that an event or action can be attributed to a person or process and cannot be denied.

This is a cornerstone of information security, but doesn’t attract the same attention as the CIA triad for example. Without it, it would be impossible to prove without doubt who was responsible for something.

One of the reasons you typically have a unique username and password at work is so that audit logs can show what actions were carried out using your account. If you share your password with others, then it is difficult to prove that you were the only one using your account. This can have negative as well as positive connotations, but we’ll look at them when we talk about passwords.

F is for…


Computers talk to each other using different protocols (these are just different formats for messages) and different protocols use different ports. Common protocols include http, which is used by most internet traffic, https which is an encrypted version of http, or FTP which is used for file transfers (File Transfer Protocol). Http uses port 80, https uses port 443, and FTP commonly uses port 21. Sounds complicated, doesn’t it?

Maybe this will help. Remember those children’s toys, with different shaped blocks that you have to push through holes in a board, like the one shown in the picture below? Think of the different shaped blocks as network traffic using different protocols, and the holes in the board are ports. The question then becomes – what is the board? That’s the firewall. A firewall sits between the internet and your internal network. In order to improve protection on your network, you close off all the ports and protocols which you don’t use on your network, which reduces the number of different ways for the bad guys to get in to your network – or to receive data from yours. Penetration testers can help you identify vulnerabilities and advise which ports and protocols should be blocked.


You probably know what forensics are when used in crime dramas. They’d very popular, and typically you’ll see people in one piece overalls combing painstakingly through a crime scene looking for clues. Digital forensics aren’t a lot different, but instead of the overalls analysts doing the work are most likely in a lab of some sort. They use various tools to examine the hard drives and memory on devices to work out who did what and when. Whether they’re looking at individual fragments of files, or using software packages to trawl to email records and logs, they’re trying to piece together what happened. As more of the world does business on line, digital forensics experts are going to be in more and more demand.


Before any kind of electronic storage eg hard drive or USB stick can be used, it needs to be prepared to receive data. Different operating systems (like Microsoft Windows, MacOS or UNIX) prepare the storage in different ways, through a process called formatting.