Availability vs Confidentiality

Why they differ

More locks protect confidentiality but can make information harder to reach; the two must be balanced.

Fundamentals

Making sure information and systems can be used by the right people when they are needed.

Formal

The property that information and systems can be reached and used on demand by those allowed to use them, within agreed times. It is lost through faults, overload, power cuts and attacks alike.

In plain English

Like a shop's opening hours - the goods are no use to anyone if the door is locked when customers arrive.

In practice

A power cut takes down the patient record system at a Danish regional hospital; for three hours doctors and nurses work from paper lists and phone calls until it is running again.

Why it matters

Every hour a key system is down can stop sales, delay care or halt production - which is exactly what attacks like ransomware aim for.

Confidentiality

Fundamentals

Making sure only the right people can see a piece of information.

Formal

The property that information is not made available or disclosed to people, systems or processes that are not allowed to have it - whether it is stored, being sent or being printed.

In plain English

Like a sealed letter - the address is on the outside, but only the person it is meant for should read what is inside.

In practice

In a municipality's HR system, salary details can be seen only by the payroll team and each employee's own manager, not by colleagues in other departments.

Why it matters

Once secret information has leaked it cannot be taken back, and a leak of personal data must be reported to the authorities and can bring fines and lasting damage to trust.

Shared connections

CIA triad