What is Tor and how does it work? – TechRadar

If you're looking to keep your online activities to yourself then Tor is a great option for your privacy toolkit.

Tor is a custom browser with clever open-source technology which uses some very smart tricks to protect your web anonymity.

It accesses both regular websites and the dark web, the hidden area of the internet which you won't find indexed on Google. Oh, and it's also free, with no registration required, no data limits, no ads and no constant demands to upgrade to a paid product.

Is Tor the perfect web anonymity tool? Not quite, but it can work very well in some situations. In this article we'll explain how Tor works, when to use it, and how you can combine Tor with a VPN to get the best possible protection.

Tor is an open-source package based around a principle called Onion Routing.

This involves encrypting your data multiple times, then passing it through a network of volunteer-run servers (or 'relays') from around the world.

The first (or 'guard') relay receives your data and peels off the first layer of encryption, like the layer of an onion. In fact, Tor stands for 'The Onion Router', and takes its name from this layering idea.

The guard relay knows your IP address but has no other clues to your identity. It can't see which site you're trying to access, either, so there's no way to log what you're doing. The only information it has is the address of the next relay.

The subsequent relays don't have your IP address or know which site you're trying to visit. All they do is remove a layer of encryption and pass the data to the next relay.

When your data reaches the last relay, also called the exit node, it removes the final layer of encryption and routes your web request to its real destination.

Your target website sees the IP address of the Tor exit node rather than yours, so has even less idea of who you are. It passes its response back to the exit node, which routes it through the Tor network and back to you.

Tor uses the same core principle as a VPN service: it hides your IP address from websites by routing your traffic through another server. But there are several differences in how the process works.

For example, while VPNs typically use a single server, Tor routes your data through at least three.

VPNs have a single layer of encryption which protects you from end-to-end; Tor uses multiple layers, but these are peeled off as you travel from server to server.

And VPNs require you to log into a server, which then sees every website you visit (and could log that data, theoretically). Tor separates the knowledge of who you are (your incoming IP address) and the website you're visiting, making it much more difficult to record your activities.

Despite Tor's powerful tech and many privacy-protecting features, it's very easy to use.

Visit the official Tor website and download the right version of Tor for your platform. There's no iOS version, but the site does have downloads for Windows, Mac, Linux and Android.

Running the installer sets your device up with Tor Browser, a special version of Firefox. This includes the extra software necessary to make Tor work, and also bundles the excellent NoScript and HTTPS Everywhere extensions for even more protection.

Launch Tor Browser and it asks if you'd like to connect to Tor. Click Connect, Tor Browser connects to a Tor guard relay, and that's it, you can get on with running searches, browsing to websites and generally using the web as normal. The only difference is your traffic is now routed via the Tor network, rather than your regular connection.

(Beware, unlike a VPN, Tor Browser only protects its own traffic. Other apps and your system still use your standard internet connection.)

Tor Browser doesn't just support accessing regular websites. It also allows you to browse .onion sites, part of the hidden area of the internet often known as the dark web. There's no extra work involved, you just type the site URL into the address bar.

The dark web is often linked to sites selling guns, drugs, stolen data and all kinds of horrifying content, but although there's some truth in that, it's only a tiny part of the story.

.onion sites aren't only used by people looking to hide something, for instance. They're also a way to bypass censorship, perhaps to get around country-level website blocks. Facebook has an .onion site at https://www.facebookwkhpilnemxj7asaniu7vnjjbiltxjqhye3mhbshg7kx5tfyd.onion , for instance, the BBC uses https://www.bbcnewsv2vjtpsuy.onion, and the DuckDuckGo search engine is at https://3g2upl4pq6kufc4m.onion (note that these .onion links won't work unless you're using Tor).

It's not always easy to find .onion sites, but there are plenty of resources that can help. The Hidden Wiki is a huge .onion site directory, DuckDuckGo's engine indexes .onion sites, and Reddit has plenty of chat and recommendations about the latest .onion discoveries.

Tor has a similar legal status to VPNs across much of the world.

The technology won't cause you any legal problems in most countries. (As long as you don't use it to order illicit items from deep web sites, anyway.)

Countries which ban VPNs, like China, Belarus and the UAE, also disapprove of Tor. That doesn't mean you'll be arrested for downloading it - China is more interested in blocking the technology, so it just won't work - but it does mean you should be more careful. If you're using a VPN anyway, combining it with Tor might prevent the authorities seeing what you're doing (more on that, later.)

Encrypting your traffic and routing it through multiple servers does a lot to protect your privacy, but there's a price to pay. It really, really, really slows you down.

How slow? We ran a speed test on a mobile device connected via Wi-Fi. This managed downloads of 50Mbps using our regular connection, and 2Mbps with Tor. Like we said... slow.

There's another potential problem, too. Many hackers abuse Tor as a way to protect their identity when they launch attacks. Platforms understand this very well, and many display warnings or block access entirely if they detect you're using Tor.

PayPal gave us a couple of extra security checks and still blocked our login attempts, for instance. Amazon let us in, but only after we'd approved a notification sent to our mobile. And Google blocked us out of YouTube entirely because 'our systems have detected unusual traffic from your computer network', it complained. Tor probably isn't going to be a good choice for your regular browsing.

Tor's big anonymity advantage is that it's decentralized. The Tor network isn't run by a single company who gets to see every connection and data path: relays are run by thousands of volunteers from around the world. There's no one point anyone can use to watch your logins, record your traffic or otherwise monitor what you're doing online.

Your own network can see you're accessing Tor, though, which might be a problem in a country which doesn't like web privacy. And although the first Tor relay doesn't need any logon credentials, it has a little knowledge about you in the shape of your IP address.

There is a potential vulnerability in the Tor exit node, too, the server which both removes the final layer of encryption and gets to see the URL you're trying to visit. If you're using an unencrypted HTTP, rather than an HTTPS connection, the node may be able to log sensitive information about your activities.

Exit nodes can also use an exploit called SSL stripping to access unencrypted HTTP communications on what you think is an encrypted site. In August 2020, security researcher nusenu unveiled research suggesting up to 23% of all Tor exit nodes were engaged in a malicious campaign targeting accesses to cryptocurrency sites, altering traffic and redirecting transactions into their own virtual wallets.

Tor goes a long way to preserving your web privacy, but it has some issues. If you're looking for maximum protection, the best approach is to combine Tor with a VPN.

The simplest route is to connect to your VPN, then Tor (a technique called 'Onion over VPN'.) Now your home network only sees your VPN IP, so it doesn't know you're accessing Tor. The first Tor relay only sees your VPN IP address, giving it no information on who you are. And your VPN can't see which sites you're browsing as they're handled by Tor, so even if a server is breached by hackers, there's no way to access your browsing history.

Tor over VPN can't protect you from malicious exit nodes, which is why some users prefer connecting to Tor first, then the VPN ('VPN over Onion'.) But that allows the VPN to see your traffic again, giving you little privacy benefit overall.

You can use Tor with most VPNs, but some have better support than others.

ExpressVPN has its own .onion site at http://expressobutiolem.onion, for instance, making it easier to access the service in countries where it's blocked (it has a great Tor guide, too.)

And NordVPN has built-in Onion over VPN support, so you don't even need the Tor browser. Just choose Onion Over VPN in the NordVPN app and it connects you to the Tor network: web privacy doesn't get much easier than that.

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What is Tor and how does it work? - TechRadar