5.1 The Internet and its uses

The Internet and the WWW

Internet vs World Wide Web

It is a common mistake to think these are the same. They are not!

  • The Internet: The global network of hardware (cables, routers, servers) that connects computers.
  • The WWW: The collection of web pages and HTML documents accessed via the internet using the HTTP protocol.

Web Browsers

A browser renders HTML into a visual page, stores cookies, and manages the URL (Uniform Resource Locator).

Concept Diagram
Figure 5.1.1: The Internet and the WWW

Blockchain and Digital Currency

Digital Currency

A currency that exists only in electronic form. It does not have a physical note or coin.

Blockchain Technology

A distributed ledger that records transactions across many computers. Once a "block" of data is added, it cannot be changed without changing all subsequent blocks.

Examiner Tip: Blockchain is secure because it is decentralized—there is no single point of failure.
Concept Diagram
Figure 5.1.2: Blockchain and Digital Currency

Cyber Security Threats

Common Attacks

  • Brute-force Attack: Attempting to guess a password by trying every possible combination.
  • Data Theft: Stealing data via hacking or social engineering.
  • DDoS (Distributed Denial of Service): Flooding a server with useless traffic to crash it.

Protecting Systems

Security Measures

  • Firewall: Monitors incoming and outgoing traffic based on a set of rules to block unauthorized access.
  • Proxy Server: Acts as an intermediary between a user and the internet to hide the user's IP address.
  • Two-Step Verification: Requires two different forms of identification (e.g., a password and a code sent to a phone).
  • Biometrics: Using unique physical traits (fingerprints, face ID) as a password.
Concept Diagram
Figure 5.1.4: Protecting Systems