Cybersecurity

(protecting systems and data: confidentiality, integrity, and availability)

What is cybersecurity?

Cybersecurity is the practice of protecting computer systems and data from unauthorized access, damage, or disruption. Its goals are usually organized around three core properties, together called the CIA triad.

The CIA triad

Confidentiality means only authorized people can see the data — a private medical record should be visible only to the patient and their care team, not to anyone else. Integrity means the data hasn't been improperly altered — a bank balance should change only through legitimate transactions, never through unauthorized tampering. Availability means the system remains usable by the people who legitimately need it — a hospital's patient records system needs to stay accessible during an emergency, not go down at the worst possible moment. Good security has to address all three; a system that's perfectly confidential but unavailable when needed has still failed at its job.

Why simple passwords are genuinely weak: counting the possibilities

A 4-digit PIN has exactly 10 × 10 × 10 × 10 = 10,000 possible combinations (10 choices for each of the 4 digits). An 8-character password using lowercase letters, uppercase letters, and digits (62 possible characters per position) has 62⁸ possible combinations — a number with 14 digits, vastly larger than 10,000. This isn't a matter of opinion: it's a direct counting fact, and it's exactly why longer, more varied passwords are harder to guess through brute-force attempts — there are simply, provably, far more possibilities to check.

Encryption, conceptually

Encryption scrambles data so that only someone holding the correct key can unscramble (decrypt) it back into its original, readable form. The number theory article covers a real, established encryption system — RSA — in full mathematical detail, including exactly why it's currently considered computationally infeasible to break without the right key.

Why cybersecurity matters

As more of daily life — banking, medical records, communication — depends on computer systems, protecting the confidentiality, integrity, and availability of that data isn't an optional extra; it's a basic requirement for those systems to be trustworthy at all.