Network Security (AQA GCSE Computer Science)

Why do we need to protect a network?

• As technology continues to advance at a rapid rate, sensitive data is increasingly stored on networks making it a target for hackers
• Computer networks face a variety of threats and they can cause a large number of issues for a network
• The main methods of securing networks are:
  • Authentication
  • Encryption
  • Firewalls
  • MAC address filtering

What is authentication?

• Authentication is the process of using credentials to check if a user is who they say they are
• Credentials are typically:
  • Usernames & passwords
  • ID badges
  • Access/security codes
  • Biometrics (finger prints, retina, voice etc.)
• Credentials are verified to see if they match what is stored by the system

When can authentication be used?

• Authentication is used in computer systems when data or services require approved access, and should not be available to everyone
• Examples include:
  • Logging into networked computers (i.e. school, office etc.)

• • Accessing online services (i.e. banking, social media, entertainment streaming platforms etc.)

What is encryption?

• Encryption is a method of converting plain text into ciphered text to be stored
• Encryption uses complex mathematical algorithms to scramble the text
• Asymmetric encryption, also known as private key, public key encryption is often used for web pages and other communication

When can encryption be used?

• Encryption should be used in any situation where sensitive data is being transmitted across a network
• Examples include:
  • Passwords
  • Bank details
  • Personal information

What is a firewall?

• A firewall is a barrier between a network and the internet
• A firewall prevents unwanted traffic from entering a network by filtering requests to ensure they are legitimate
• It can be both hardware and software and they are often used together to provide stronger security to a network

When can a firewall be used?

• Hardware firewalls can be used to protect a whole network and prevent unauthorised traffic, they usually come built in to a router 
• Software firewalls can be used to protect an individual device on the network, monitoring the data going to and from each computer, they are usually installed as part of the operating system

What is MAC address filtering?

• MAC address filtering is the process of using a devices MAC address to determine if a device can or cannot connect to a network
• Devices with MAC address that are allowed to connect are placed on a ‘white list’, and those not allowed on a ‘black list’
• If a device tries to connect to a network and the MAC address is not on the list, connection is refused
• A MAC address is a unique identifier embedded into a device during manufacturing
• MAC addresses are given to any device capable of connecting to a network, wired or wirelessly

When can MAC address filtering be used?

• MAC address filtering is predominantly used on wi-fi networks to limit access to the network to only devices on the ‘white list’
• Only approved physical devices can connect to the network