Network security

Computer networks have many benefits but they also create security risks. By connecting computers it is possible to share personal data easily. However, it makes computers more vulnerable to interference from other people.

Anyone sharing personal information, eg bank details, wants to be sure that they are safe and secure. Most businesses and organisations employ network managers or administrators to manage the security of their networks.

There are many potential threats to a network and various ways to protect them.

What is network security?

Anti-virus software

There are a number of malicious software (‘malware’) programs that can cause damage to computers. These include viruses, worms, zombies, Trojan horses (Trojans) and Spybots.

Anti-virus software is designed to detect and block attacks from malware. Some operating systems have their own inbuilt anti-virus software.

In a large organisation, a network manager should make sure that all the computers under their control are secure and the anti-virus software is up to date.


A firewall is software that will block unexpected connections coming in to the network. Most operating systems include a firewall.

Secure passwords

When more than one person uses a network it is important to have user IDs and passwords. Only someone with a login and password can access that network. It also helps the network manager trace unusual activity to a specific user.

A weak password makes it easy for someone to try to guess your login details. A good password will have a mix of upper case and lower case letters, numbers and special characters.

Access levels

In a large company or school, many people will be using computers on the same network. A network manager will normally control the level of access people have to the network. General users will not have the ability to download any software they want or to make changes to any part of the system, as that could affect other users.

The more people have access to sensitive parts of the network, the more likely it is that a hacker or a virus might be able to cause damage.

You can set user access levels on your home computer. For example, a parent may prevent a child from being able to install software.


An explanation on why it's important to encrypt files containing sensitive information

Any message sent over a network can be intercepted. Encryption is a method of changing the original numbers and characters so that they are hidden or disguised. This is important if you are sending sensitive information.

One method of encryption is the Caesar Cipher algorithm. In this method, each letter of the alphabet is simply replaced by another letter in the alphabet that might be one or more letter positions away.

For example, encrypting using letters which are +5 positions away would change the original text ‘Bitesize’ into cipher text ‘Gnyjxnej’.

The prefix for some web addresses is https instead of http. The ‘s’ indicates that it is a secure website and any payment or personal details that are inputted into the site will be encrypted.