I mean there are a lot of resources but they are at a very high level. I don't think much has changed.

The basic idea is that with Tor, you make HTTPS connections to the "tor relay", a network of volunteers who route your traffic around the world to make it hard to track. You can use Tor in two ways: you can join the relay network and route traffic for others, or you can just use the browser and make queries. If you do decide to join the relay network you have an additional decision about whether you will be an "exit node", one that does the final request to the destination website and thus appears to be the initiator of the request. This is an option because it can be difficult on home internet setups: if someone uses your exit node to post a lot of stupid crap to Reddit and Reddit tries to IP-ban them, then you are suddenly IP-banned from Reddit at home, because you ran the exit node.

If you are just a user then the only thing you need to know is that there is a price for your privacy, which is that routing your traffic all the way around the world takes a little more time than sending it straight to you, and this has two effects -- a latency jump which exists basically no matter how big the network gets, and a slowdown in your bandwidth which depends on how big the network is relative to the number of people trying to browse with it.

> if someone uses your exit node to post a lot of stupid crap to Reddit ...

I think there’s a lot more to worry about than reddit shitposts eg straight up criminal activity apparently coming from your router, and in way you’d have difficulty proving was tor and not you or your family.

How is malicious interference by exit nodes prevented for plaint-text HTTP requests?

A subset of relay operators & other volunteers monitor the network for bad actors and report them to Tor Project who will then direct directory authority operators to blacklist those relays.

One of those volunteers is nusenu: https://medium.com/@nusenu/the-growing-problem-of-malicious-...

It can't be prevented on a technological level. However there are attempts to detect bad nodes and ban them. Since the exit node doesn't know "who" is accessing the website it can't just temper with your content. So it would be detected asymptomatically.

I would have to say "it's not".. anything non-encrypted you risk being manipulated by a node of the TOR network. I bet there are people who act as relays just to try to sniff out any good non-HTTPS traffic.. although, I suppose generally anyone using TOR is mostly aware of this so there's probably not that much to gain.

Complete side note.. but this just reminds me of back when I was in college in the late 90s, and our entire apartment buildings traffic was a hub (not a switch).. so I had a packet sniffer running for fun on linux and could see everything from everyones internet since every single packet was rounting to every machine on the network, and lots of stuff had no encryption... nuts to think how open stuff was back in the day.

Pretty sure some switches (to this day) can be tricked into doing similar. eg send them a few specially crafted packets, and they fall back into broadcasting ~everything like a hub for some period of time.

Not from the point of view of "legal intercept" stuff, more like "switch gets confused and doesn't know how to route, so broadcasts as a workaround".

I highly recommend Computerphile's explanation of Onion Routing: https://www.youtube.com/watch?v=QRYzre4bf7I

After that, check out the video explaining how hidden services work.

If you want to see a simple implementation of an onion router, I built one in TypeScript: https://github.com/seisvelas/onion-router-ts

(be warned, I also did that as an exercise to learn more TypeScript. So it's not good TS. But improvements and issues are more than welcome from any TS gurus out there!)

Computerphile is truly a gift to us all

It’s such an unfortunate name to use though!

It fits with the other channels by Brady Harren, though he no longer produces the videos for computerphile.

Why is that?

I assume that GEBBL is either only familiar with the -phile suffix in the context of 'pedophile', or is implying that that could be the case for others.

I think your repo is private, I get a 404

Indeed it was! I just made it public, thanks for saying something :)

If you're thinking about risks, it's important not to conflate 3 scenarios: (1) running a Tor exit node (potentially very risky), (2) running a Tor relay node, and (3) just using the Tor browser as a user (should probably be fine for most users - depends on what you use it for of course, and Tor by itself is of course not sufficient to solve all privacy issues - you can still be deanonymized if you're not careful).

Do you have any more information on how one could be deanonymized using Tor? I am aware of the browser fingerprinting and Tor themselves has a decent article about it but are there other methods that malicious parties could use?

https://blog.torproject.org/browser-fingerprinting-introduct...

To use an obvious example, if you log into an account you've previously logged into directly from your home computer.

More broadly, any privacy tech can be undone by poor 'operational security'. For example Ross Ulbricht - 'Dread Pirate Roberts' of Silk road - posted on StackOverflow under his own name to ask "How can I connect to a Tor hidden service using curl in php?" [1]

[1] https://arstechnica.com/information-technology/2013/10/silk-...

Well a big one would be putting personally identifiable information on websites inside or outside the tor network.

You could use Brave browser, it includes a Tor client which is accessed through the "new private window with Tor" menu item. I assume downloads of Brave might not be tracked by the US government, but then again, everything is tracked, it's just a matter of what behavior is likely to be flagged by an agency's algorithms.

It's true. Same applies with Tails. If your employer is one of the few with intelligence community shadow relationships,they will likely be alerted as well.

You will also be targeted for browser exploitation without a warrant. Tails in an isolated environment is probably the best way of using Tor.

The Tor Browser is scrutinized heavily. I know that is kind of a fallacious argument, but they have a routine presence at DefCon and they are really committed to protecting people around the world. At DefCon last year, the Tor project talked about the biggest security concern as countries who monitor the entry points to the network, and the challenges with getting those IPs distributed confidentially and keeping them hidden. (If you don't already know, Tor does require an entry IP address list before the anonymization occurs: countries can arrest people who visit these URLs, so this is the big challenge right now.)

Someone who knows more can probably elaborate, but after hearing them present year after year, and how much global advocacy they engage in, and their transparency, I find it unlikely they have NSA spooks embedded.

I use it when I need to read something objectionable through a VPN. (Still not perfect, because I run a VPN on EC2 and the exit zone is in the US...)

Not trying to be flame-baity here, but with Trump's ranting about making ANTIFA a terror org, and with the recent legislation that allows warrant-less IP tracking, I am legitimately concerned I might end up on a watch list because I visit a website this admin finds objectionable.

> If you don't already know, Tor does require an entry IP address list before the anonymization occurs: countries can arrest people who visit these URLs, so this is the big challenge right now.

Sorry, can you explain what this means? Would my home IP address be the "entry IP address" you're referring to?

No, it's the IP of the first relay.

Tor works pretty much like this:

You -> Relay 1 -> Relay 2 -> Relay 3 -> The website

Each arrow is an encrypted connection. The content of the exchange on a single arrow is the address of the next hop and the query of the next hop. Thanks to this:

- Relay 1 only knows you're going through Relay 2

- Relay 2 doesn't know who's asking (you) but knows it passed through Relay 1 and is going through Relay 3

- Relay 3 doesn't know who's asking (you) and where you entered, but knows it's going to the website

The nodes in the middle know everything that goes through them, but don't have the big picture.

The entry IP address is the IP address of Relay 1. Your computer must know an address to connect to, and that address is distributed in listings by the Tor Project. Since this listing is public, it also makes it easier for censors to censor, or at least detect who's interested in connecting through Tor

Do you know if GDPR prevents EU countries from obtaining IP logs for Amazon zones located there? I was hoping I could spin up an EC2 VPN in Europe and feel more secure that my IP logs can't be obtained by the US gov't. I use RunBox for email in Norway, which has the strictest privacy laws, but there is no AWS zone there. Any thoughts? Thanks.

The US CLOUD Act was designed specifically to enable US gov agencies to access that information:

https://en.wikipedia.org/wiki/CLOUD_Act

So, don't use EC2 or stuff hosted by other US companies for things to you want to keep private from the US gov.

Also note the US gov shares intelligence with other countries, as mentioned by a sibling post.

Maybe through the UKUSA agreement or similar. https://en.m.wikipedia.org/wiki/UKUSA_Agreement

> Do you know if GDPR prevents EU countries from obtaining IP logs for Amazon zones located there?

GDPR has specific exemptions for law enforcement and national security. Governments are allowed to get the data by claiming it's for national security. Some EU countries may have better protections than others.

To give better advice I guess people would want to know what your risk model is. Who do you think is after your data? What do you want to protect?

> risk model is

Mostly curiosity: what is the highest degree I can obscure my web use and meta data with off-the-shelf technologies?