Does accessing a personally owned Tor node (that only you ever visit) over the Tor network break anonymity?

Question

Does accessing a personally owned Tor node (that only you ever visit) over the Tor network break anonymity?

I read from a long guide by Whonix on how to properly use Tor that I shouldn't ever access small personal clearnet websites over the Tor network (e.g. personal blog). For obvious reasons this is bad because you would be a be a likely visitor of your own blog and that information could be used by the exit node to deanonymize your entire Tor connection.

So, what I want to know is if the same thing applies to Tor nodes you operate. I run my SSH over Tor and was curious. (I use Qubes-Whonix if that's at all relevant)

Thank you! :D

Answer 1

No!

This is exactly what Tor hidden services are designed to accomplish.

Nothing is absolutely safe and given enough worldwide oversight and resources, Tor is vulnerable in theory. In practice the vulnerability bar is very very very high.

If you are the only user of your hidden service, you may want to make it a "Stealth Hidden Service". This requires an additional key in your Tor client, so it doesn't scale well and may limit how you chose to use it, but it adds yet more anonymity by making it difficult to identify that it exists even in the master hidden service directories.

One seemingly counter intuitive aspect is: do NOT use HTTPS on your hidden server! The Tor connection is already multiple encrypted so you don't need it for security. Worse, it may result in your client calling outside Tor to check the certificate authenticity which only you use, that might compromise your anonymity.

Answer 2

If you use this Tor node as an exit node, then yes. Unless you purchased the service anonymously in a way that cannot be traced back to you (note that most cryptocurrency is only pseudonymous, real anonymous payment is very hard to do correctly), using your own exit node is going to break anonymity.

For entry node, this is less of a concern. Although, you might want to increase the number of hop if you do this because you're essentially entering the anonymity network only from the second hop onwards.