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Glossary

One plain sentence for every jargon term used in this guide.

  • Threat model — Your answer to "who might come after me, and what would it cost me?" It decides which defenses are worth your time.
  • Attack surface — Everything an attacker could reach: every open port, every account, every installed app. Smaller is safer.
  • 2FA (two-factor authentication) — Logging in with two different kinds of proof (something you know plus something you have), so a stolen password alone isn't enough.
  • Passkey — A login credential stored on your device that proves who you are with a fingerprint or PIN — phishing can't steal it because there's nothing to type into a fake page.
  • Phishing — Fake messages (email) designed to trick you into handing over passwords or clicking something malicious.
  • Smishing — Phishing by text message.
  • Vishing — Phishing by voice call.
  • Credential stuffing — Taking passwords leaked from one site and trying them on many others, betting that you reused them.
  • Malware — Any software that does harm: viruses, trojans, spyware, all of it.
  • Ransomware — Malware that locks your files and demands payment for the key.
  • Firewall — A gatekeeper that blocks network traffic unless a rule allows it.
  • VPN (virtual private network) — An encrypted tunnel from your device to another network. It hides your traffic from the local network — it does not make you anonymous or immune to scams.
  • SSH (Secure Shell) — The standard way to get a command line on a remote machine, encrypted.
  • Port forwarding — A router rule that sends traffic arriving on a port from the internet to a specific machine inside your network.
  • Honeypot — A fake, tempting machine that exists to watch what attackers do.
  • fail2ban — A tool that temporarily blocks IP addresses after too many failed login attempts.
  • UPnP (Universal Plug and Play) — A router feature that lets devices open port-forwarding rules by themselves, with no password and no asking you.
  • WPA2 / WPA3 — The security standards for Wi-Fi passwords. WPA3 is newer and better; WPA2 is still fine with a strong password.
  • Backup 3-2-1 — Keep 3 copies of important data, on 2 different kinds of storage, with 1 copy offsite.
  • Social engineering — Manipulating a person into handing over access, instead of breaking the technology. Most scams are social engineering.
  • Zero-day — A bug attackers know about before the software maker does, so there's no fix yet. You can't defend against a specific zero-day — you defend by updating fast once the fix ships.