Level 1 · 0A Start here · Lesson 3 of 3
The three things we protect
Everything cybersecurity does can be summed up as protecting three things. Professionals call them the CIA triad: Confidentiality, Integrity and Availability. In plain words: what's secret stays secret, what's true stays true, and what you need is there when you need it.
Confidentiality: only the right people can see it
Your bank password, your messages, your photos. It's lost when someone who shouldn't see something sees it, for example in a data leak or if someone spies on your connection.
Integrity: nobody changes it without permission
That the amount of a transfer is the one you entered, that nobody else changes your university grade, that the file you download is the original and not a copy with a virus. It's lost when someone changes something and you don't notice.
Availability: it's there when you need it
That the bank's website loads, that your files aren't held hostage, that the service doesn't go down right when you're using it. It's lost with an attack that knocks a site offline or with ransomware (a program that locks your files and demands money) blocking your files.
Going deeper
Typical defenses for each one
For confidentiality: encryption and permissions. For integrity: digital signatures and checks that detect changes. For availability: backup copies and keeping a duplicate of what matters. The whole course revolves around these three ideas.
Review questions
An attacker publishes a company's private messages. What was lost?
Answer: Confidentiality. What was secret was seen by someone who shouldn't have: that's confidentiality.
A virus changes the account number of a transfer without you noticing. What was lost?
Answer: Integrity. Someone changed data without permission: that's integrity.
A store's website goes down because of an attack in the middle of Black Friday. What is affected?
Answer: Availability. The service stopped being there when people needed it: that's availability.