Methods of Securing a Network (Edexcel IGCSE Ict)

Usernames & Passwords

Spec point — 2.5.1

How does a password help?

• Passwords are a digital lock to prevent unauthorised access to an account
• Passwords are used to authenticate **a user to the network
• They are often stored as an encrypted/ciphered text entry in a database, ensuring that even with unauthorised access to a database, a hacker would not be able to gain access to the individual passwords of users -** Strong passwords and regular password changes are important to maintain security

Firewalls

Spec point — 2.5.1

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

  • Hardware firewalls will protect the whole network and prevent unauthorised traffic
  • Software firewalls will protect the individual devices on the network, monitoring the data going to and from each computer

Encryption

Spec point — 2.5.1

What is encryption?

• Encryption is a method of scrambling data so that unauthorised users cannot understand it

• Encryption methods use 'keys', which are specialised programs designed to scramble or unscramble data

• Encryption uses complex mathematical algorithms to scramble the data

• There are two common methods of encryption:

  • Symmetric
  • Public key

Symmetric encryption

• The sender uses a key to encrypt the data before transmission
• The receiver uses the same key to decrypt the data
• It's usually faster, making it ideal for encrypting large amounts of data
• The significant downside is the challenge of securely sharing this key between the sender and receiver
• If an unauthorised user captures the key, they can decrypt all messages intercepted in transmission

Structure of Symmetric Encryption

Public key encryption

• Public key encryption uses two keys:

  • a public key for encryption
  • and a private key for decryption

• Receivers openly share their public key

• Senders use this public key to encrypt the data

• The receiver's private key is the only key that can decrypt the data and is kept locally on their side

• The public and private keys are created at the same time and are designed to work together in this way

• It is typically slower than symmetric encryption

• It is generally used for more secure and smaller data transactions, e.g. passwords, bank details

Structure of Public Key Encryption

WEP/WPA

Spec point — 2.5.1

What is WEP?

• Wireless Encryption Protocol (WEP) is a method of encrypting data being transmitted on a wireless network
• Each device on the network uses the same key to encrypt and decrypt data
• It is a less secure encryption method due to all devices on the network sharing the same key
• Eavesdropping software (packet sniffers) can be used to intercept data packets and identify the key

What is WPA?

• Wi-fi Protected Access (WPA) is a more secure method of encrypting data being transmitted on a **wireless **network
• Each device connected to the network receives a different key
• New keys are used for** every packet** transmitted on the network

Virtual private networks (VPN)

Spec point — 2.5.1

What is a VPN?

• A VPN allows users to remotely connect to private local area networks (LANs)

• All data sent and received using a VPN is encrypted

• Common uses of a VPN include:

  • Remotely accessing a companies network (working from home)
  • Making secure payments
  • Hiding web activities
  • Bypassing geolocation rights management or online censorship

File access rights

Spec point — 2.5.1

What are file access rights?

• File access rights can be set to determine different levels of access to specific files/folders

• Examples of file permissions include:

  • Read- can read the contents of a file only
  • Write- can make changes to file contents and/or create new files
  • Delete- can delete files
  • Execute- can run applications/launch software

Transaction logs & backups

Spec point — 2.5.1

What is a transaction log?

• A transaction log is a secure file on a network that keeps a record of every action performed by devices on a network

• Transactions logs include:

  • Device & data access
  • Timestamps
  • User IDs
  • Successful/failed login attempts

• Transaction logs don't directly protect a network, they help administrators monitor any identify any unusual activity

• Backups are another indirect method of protecting a network

• Keeping copies of data in a secure place on the network in the event of a data breach/loss

Worked Example Describe one method that could be used to secure payment data transferred between a server and other computers

[3]

Answer

A description to include three linked points:

• Encryption [1] encodes/scrambles data / makes data unreadable [1] using a key [1]