What is cybersecurity?

The short answer

Cybersecurity is protecting computers, networks and data from people who want to steal, break or misuse them. It covers everything from your phone's lock screen to the systems that run banks, hospitals and power grids.

It isn't only about hackers in hoodies. Most real incidents start with something ordinary: a reused password, an unpatched server, or someone clicking a convincing email.

The CIA triad

Security people judge every system against three goals, known as the CIA triad. Almost every attack breaks at least one of them.

• Confidentiality: only the right people can see the data. A leaked database breaks this.
• Integrity: the data hasn't been changed without permission. A tampered bank transfer breaks this.
• Availability: the system works when people need it. A website knocked offline breaks this.

Who attacks, and why

Attackers range from bored teenagers running ready-made tools, to criminal gangs selling stolen data and running ransomware, to government teams spying on other countries. Most are after money. Some want attention, information or disruption.

Most attacks are automated. Bots scan the whole internet around the clock looking for weak passwords and old software, so even a small home server gets probed within minutes of going online.

Defence in depth

No single protection is perfect, so good security stacks several layers: strong passwords, two-factor login, a firewall, regular updates, backups, and logs you actually read. An attacker who gets past one layer still hits the next.

Try it

Look at one account you use every day. Which part of the CIA triad would hurt most if it failed? Then turn on two-factor login for it.