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by StavrosK 2073 days ago
How confident are we that Tor is compromised?
3 comments

> How confident are we that Tor is compromised?

Large scale actors (read: ISPs and government agencies) have a huge amount of entry and exit nodes. They can simply measure timestamps and stream bytesizes, which allows them to trace your IP and geolocation.

They do not have to decrypt HTTPS traffic for that, because the order of those streams is pretty unique when it comes to target IPs and timestamps.

I was under the impression that Tor hidden services were still safe since they don't rely on exit nodes.
Yes, hidden services are safe (well, no system is really safe). But if e.g. a hidden service includes a web resource from the clearnet, it can be traced.

I was talking about the "using tor to anonymize my IP" use case, where exit nodes get a huge amount of traffic per session.

In order to be really anon you would need a custom client side engine that randomizes the order of external resources, and pauses/resumes requests (given 206 or chunked encoding is supported), and/or introduces null bytes to have a different stream bytesize after TLS encryption is added.

Hidden services are safer in the sense that your connection can't be deanonymized with the help of your third relay (which would have been an exit node in the case of a clearnet connection) but if the hidden service in question were to be a honeypot and your entrypoint (ISP or tor guard node) were to be monitored by the same entity (this second requirement also holds for clearnet connection monitoring BTW), it would be possible to deanonymize your connection to the hidden service.

How easy it is to perform the traffic analysis would have to depend on the amount of data being transferred, if I had to guess, so downloading a video would probably be worse than browsing a plaintext forum like hackernews. But if we're talking about a honeypot, your browser could be easily tricked into downloading large-enough files even from a plaintext website (just add several megabytes of comments in the webpage source for instance).

> In order to be really anon you would need a custom client side engine that randomizes the order of external resources, and pauses/resumes requests (given 206 or chunked encoding is supported), and/or introduces null bytes to have a different stream bytesize after TLS encryption is added.

It's unclear to me how any of this helps avoid traffic analysis. I believe tor already pads data into 512-byte cells, which might help a little bit.

If you were interested in intelligence, and you wanted to maintain that pipeline of intelligence, would you give up that information?

Act in plain sight and do good, and you’ll be ok.

We aren't. This is mostly FUD.