Internet vs the World Wide Web

• The internet is the global network of networks — the physical/wireless infrastructure and connections that let devices communicate.
• The World Wide Web (WWW) is the collection of websites and web pages (accessed with HTTP/HTTPS) that runs on the internet.

Key point: the WWW is just one service that uses the internet. Email and file transfer also use the internet but are not the web.

Internet or web?

URLs, HTTP/HTTPS & browsers

A URL (Uniform Resource Locator) is the web address of a resource, e.g. https://www.example.com/page.html. It has a protocol (https), a domain name (www.example.com) and a path/file (page.html).

• HTTP (HyperText Transfer Protocol) — the rules for transferring web pages.
• HTTPS — the secure version; data is encrypted (using SSL/TLS), shown by a padlock. Use it for logins and payments.
• Web browser — software that requests, renders and displays web pages, runs scripts, stores bookmarks/history and manages cookies.

Why HTTPS?

The Domain Name System (DNS)

Humans use easy domain names (like example.com), but computers route data using numeric IP addresses. The DNS acts like a phone book: it translates a domain name into its IP address.

What DNS does

Cookies & digital currency

Cookies are small text files a website stores on your device. Session cookies are deleted when the browser closes; persistent cookies stay to remember logins, preferences or items in a basket next time you visit.

Digital currency exists only electronically (no physical coins). Cryptocurrencies use a blockchain — a shared, tamper-evident record of every transaction held across many computers, so it is very hard to alter.

Blockchain idea: each transaction is added as a ‘block’ linked to the previous one; because everyone holds a copy, fraud is easy to spot.

Cookies

Cyber-security threats

• Brute-force attack — trying many password combinations until one works.
• Denial of service (DoS) — flooding a server with requests so it cannot respond to real users.
• Phishing — fake emails/messages that trick users into revealing personal data.
• Pharming — malicious code redirects users to a fake website even if they type the correct address.
• Malware — harmful software such as viruses, worms, trojans, spyware and keyloggers.
• Data interception — ‘sniffing’ data as it travels across a network.

Name that threat

Tap a description, then tap the group it belongs to.

Keeping data safe

• Firewall — monitors and filters traffic between a device/network and the internet, blocking unauthorised access.
• Anti-malware / anti-virus — detects and removes malicious software.
• Strong passwords and two-factor authentication (2FA) — make brute-force and stolen-password attacks far harder.
• Encryption (e.g. HTTPS) — makes intercepted data unreadable.
• User awareness — not clicking suspicious links, checking the padlock/URL, keeping software updated to patch weaknesses.

Match the threat to its description

Tap a description on the left, then its matching threat on the right.

Which defence?

Spot the attack

The big ideas to know

You’ve covered the whole of The internet and its uses. Press Finish to see your score.