Two things Tor does well: it stops your provider seeing which sites you visit, and it stops those sites working out where you are. It does nothing about what you type, what you download, or which accounts you sign into. Almost nobody comes unstuck because of the network. They come unstuck because of that second list.
This goes through both properly. It assumes you’ve read the introduction, or at least know your traffic crosses three relays.
What your provider sees
Normally, a list. Every site you connect to, logged, and in much of Europe kept for months because the law says so. Encryption hides what you read once you arrive. It doesn’t hide that you knocked.
With Tor they see an encrypted connection to one machine and nothing after that. Whether you spent the evening on the news or on a medical forum is not something they can answer.
They can still tell you’re using Tor. The entry relay list is public, so a connection to one is recognisable as what it is. Tor doesn’t hide its own existence from your network — not by default, anyway. There’s a way around that further down.
What the site sees
Normally your IP address, which gives away your rough location, your provider, and lets them recognise you next time.
Through Tor they see the exit relay instead. Could be in another country. Definitely shared with a lot of other people. Your location, your provider and your identity don’t come into it.
The browser also strips and clears most of the machinery used to follow people between sites, so you arrive as a visitor rather than a returning one.
What it doesn’t hide from anyone
This is the part that matters.
Anything you tell a site yourself
Sign in somewhere with your real name attached and you’ve handed over exactly what the routing was protecting. Typing your email into a form does it. Paying with a card does it.
Obvious when it’s written down. Still the most common way people undo themselves, usually by logging into one ordinary account out of pure habit in the middle of doing something they wanted kept separate. Keeping identities apart is a habit, not a setting, which is why it’s the first thing to slip.
Unencrypted connections at the exit
The exit relay has to read the address it’s contacting — that’s its job. If the connection onward to the site isn’t itself encrypted, it can read the contents too.
Anyone can run an exit. Most operators are volunteers doing it out of conviction, some aren’t, and you don’t get to know which one you’ve been handed.
The defence is the padlock and an address starting https. Tor Browser pushes for encrypted connections wherever it can, but if you end up somewhere without one, assume everything you send is readable. On onion services this particular problem disappears, because there’s no exit at all.
Files, coming and going
A download sitting on your disk is harmless. Open it outside the browser and it can make its own connection, on your real IP, announcing you. That trick is old and still works.
Files you send out are a separate problem nobody mentions. Photos carry the coordinates of where they were taken. Documents carry the name of whoever’s computer made them. Both invisible unless you go looking, both travelling with the file. Stripping that before sharing anything matters more than most people realise.
Your own machine
Tor protects a connection. It has nothing to say about the computer at the end of it. Malware already installed reads what you type before the network is involved at all, and clipboard-swapping malware is the variety that takes the most money off people.
Being recognisably yourself
How you write. When you’re awake. The subjects you keep circling back to. The detail you can’t resist mentioning. None of that is touched by routing, and investigators have tied accounts to people on considerably less.
Can people tell you’re using it?
By default yes — your provider, and anyone watching your network.
Where that’s a problem there are bridges: entry relays that aren’t in the public list, so connecting to one doesn’t announce itself. Some go further and disguise the traffic to look like something ordinary. They exist mainly for people in countries where Tor is blocked, but they’re available to anyone. The installation walkthrough covers switching one on.
They’re not magic. A determined national censor can often still spot the pattern. Bridges raise the cost of noticing you. They don’t make you invisible.
Does a VPN help?
People ask constantly. Usually not much, and sometimes it makes things worse.
The case for: your provider sees a connection to the VPN rather than to Tor. True. Also exactly what bridges were built for, and bridges do it better.
The case against: you’ve added a company that knows both that you use Tor and when. You’ve swapped a provider you didn’t choose for one you did, and you’re still trusting somebody. VPN companies have handed over records before, having promised they kept none.
There’s a quieter cost too. Tor Browser spends a lot of effort making its users look identical. An unusual setup makes you less like everyone else, not more.
For most people, most of the time, the browser as it ships is the better answer. The Tor Project’s own support pages take much the same line, if you’d rather not take mine.
The one nobody has fixed
Someone who can watch traffic entering the network near you and leaving it near your destination, at the same time, may be able to match up the timing and connect the two. No encryption needs breaking for this to work.
Doing it requires visibility across large stretches of the internet, which puts it out of reach of most adversaries and within reach of a few. Tor has defences that make it harder. The project treats it as open research rather than something solved, which is the honest position.
For nearly everyone this isn’t the threat that matters. Know about it anyway, because a tool that states its limits is more trustworthy than one that doesn’t, and because anyone telling you Tor makes you untraceable is overselling.
How to hold all this
Tor protects the route. It doesn’t protect the content of what you decide to do.
If what you’re worried about lives somewhere between you and the site, Tor probably helps. If it’s something you typed, downloaded, signed into, or gave away by habit, it doesn’t, and no configuration will change that.
None of the items on that second list have changed in twelve years, while nearly everything about the software has. Which is why the habits built around these limits are worth more than any setting you change once and forget about.
The same gap between assumed and actual protection turns up in money too. Bitcoin isn’t anonymous either.
Next
Developing good habits is the practical half of this article. Installing Tor Browser if you haven’t yet. Onion services remove several of these limits by never leaving the network.