Threat Modelling

Anonymous from whom? The question that decides everything downstream — and the one every VPN advert skips.

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Rookmentor

Before we talk about a single tool, one question. Anonymous from whom?

Wrenlearner

Everyone? Isn't that the point of privacy?

Rookmentor

That answer is why most people buy something they do not need and skip the thing they do. Hiding from an advertiser and hiding from a government are different problems with different answers.

Adversaries, in order of how much they can do

A threat model is just four honest answers: what you want to keep private, who wants it, what happens if they get it, and how much trouble you will actually go to. Everything else follows from those.

1Advertisers and data brokers   -> want a profile, buy data, never target you personally
2A stalker or abusive ex        -> knows you, may have had physical access to your devices
3Your employer or school        -> controls the network and often the laptop
4Local law enforcement          -> can compel a company to hand over records
5A nation state                 -> can do essentially all of the above, plus more

Line 2The most common real adversary, and the one almost no privacy guide is written for. Physical access changes everything.
Line 5If this is genuinely your adversary, a VPN is not your answer and this lesson is not enough. Talk to an organisation that does this work.

Someone is worried their ex-partner is tracking their location. Which of the five above is the adversary, and does a VPN help?

Magpieadversary

And from my side of it: I do not break encryption. I look for the account you forgot, the photo with the location still in it, the username you reused since you were fifteen.

Rookmentor

Which is the real lesson. People are almost never caught by broken cryptography.

What this looks like in practice

What a photo tells anyone who receives it

# a holiday snap, straight off a phone
$ exiftool holiday.jpg | grep -i gps
GPS Latitude       : 51 deg 300 26.04" N
GPS Longitude      : 0 deg 70 39.93" W
GPS Position       : 51.507233, -0.127761
# that is a doorstep, to five metres

You use a VPN and sign into your normal Google account. Are you anonymous?

Threat model by vibes

I want to be private
  -> buy the VPN with the best advert
  -> install nine browser extensions
  -> feel safer
  -> change nothing that mattered

Threat model written down

Protecting: my home address
From:       one specific person
If it fails: physical danger
Effort:     high, this matters
  -> audit shared accounts and devices
  -> strip metadata before sending photos
  -> separate identity for public posting

The right-hand column costs nothing and is the entire discipline. Tools come after this, chosen to fit it.

Legal

Everything taught here is for protecting yourself and systems you own or are authorised to test. Using it against anyone else is both a crime and the opposite of the point.

Next: what a VPN genuinely does, and the four things it does not — including why more extensions can make you easier to follow rather than harder.