The three goals of security

Security professionals describe their whole job with three goals, known as the CIA triad. It has nothing to do with any spy agency.

• Confidentiality: only the right people can see the data. (Only you can read your messages.)
• Integrity: the data is correct and has not been tampered with. (Your bank balance is accurate.)
• Availability: the system works when you need it. (The site is up during exam registration.)

Almost every attack threatens one of these three. A leaked password breaks confidentiality. A changed grade breaks integrity. A website knocked offline breaks availability.

When you defend a system, always ask: which of the three am I protecting here?

Practice

For each case, name which part of the triad is broken: (a) a hacker reads private health records, (b) a virus deletes a hospital's files, (c) a website is flooded so patients cannot book appointments.