Security Glossary

Security professionals love their acronyms and technical terms. The problem is that most people are not security professionals. This glossary is meant to cut through the jargon and give you plain, simple definitions for the terms you are most likely to run into.

Antivirus

Software that scans your computer for malicious programs and removes them. Think of it as a security guard for your files. It is not foolproof, but it catches a lot of common threats before they cause damage.

Data Breach

When someone gains unauthorized access to a collection of personal information - names, emails, passwords, credit card numbers. You have probably received one of those "we regret to inform you" emails from a company. That is a data breach notification.

Encryption

A way of scrambling information so that only authorized people can read it. When you see that little padlock icon in your browser, it means the connection between your computer and the website is encrypted. Anyone trying to eavesdrop would see gibberish instead of your data.

Firewall

A barrier between your computer (or network) and the outside world. It monitors incoming and outgoing traffic and blocks anything that looks suspicious. Most operating systems come with a built-in firewall already turned on.

Identity Theft

When someone uses your personal information - your name, Social Security number, credit card details - to pretend to be you. They might open accounts, make purchases, or file tax returns in your name. Protecting your personal data is the best prevention.

Keylogger

A type of malicious software that records every keystroke you make on your keyboard. This is one way criminals steal passwords and credit card numbers. A good antivirus program will detect most keyloggers.

Malware

Short for "malicious software." This is the umbrella term for any program designed to harm your computer or steal your data. Viruses, spyware, ransomware, and trojans are all types of malware.

Multi-Factor Authentication (MFA)

Also called two-factor authentication or 2FA. This is when a website asks you to verify your identity in more than one way - for example, entering your password and then typing in a code sent to your phone. It adds an extra layer of protection so that even if someone steals your password, they still cannot get in.

Patch

A software update that fixes a security hole or bug. When your computer or phone asks you to install updates, it is often patching vulnerabilities that attackers could exploit. Keeping your software up to date is one of the simplest things you can do to stay safe.

Password Manager

A program that stores all your passwords in one secure, encrypted vault. You only need to remember one master password. The manager can also generate strong, unique passwords for each site you use. This is much safer than reusing the same password everywhere.

Phishing

A trick where someone sends you a fake email, text message, or website that looks legitimate - like your bank or a popular service - to get you to hand over personal information. The name comes from "fishing" because the attacker is casting a line and hoping you will bite.

Ransomware

A type of malware that locks your files or your entire computer and demands payment (a ransom) to unlock them. It often spreads through email attachments or infected websites. The best defense is regular backups and being cautious about what you click on.

Social Engineering

The art of manipulating people into giving up confidential information. Instead of hacking a computer, the attacker hacks a person - using trust, urgency, or fear. Phishing is one form of social engineering, but it also happens over the phone and in person.

Spyware

Software that secretly monitors your activity - what websites you visit, what you type, what files you open - and sends that information to someone else. It often gets installed without your knowledge, bundled with free software or through malicious links.

Trojan

Named after the Trojan horse from Greek mythology. A trojan is a malicious program disguised as something harmless or useful. You think you are installing a game or a utility, but you are actually letting an attacker into your system.

VPN (Virtual Private Network)

A service that creates an encrypted tunnel between your device and the internet. It hides your browsing activity from your internet provider and makes it much harder for anyone on a public Wi-Fi network to snoop on what you are doing. Useful when you are at a coffee shop or airport.

Virus

A specific type of malware that attaches itself to legitimate files or programs and spreads when those files are shared. Like a biological virus, it replicates itself. The term is often used loosely to mean any type of malware, but technically it is just one category.

Zero-Day

A security vulnerability that the software maker does not know about yet. It is called "zero-day" because the developers have had zero days to fix it. These are especially dangerous because there is no patch available when attackers start exploiting them.

This glossary covers the basics, but security is a broad field. If you come across a term that is not listed here, feel free to reach out and I will add it.