Questions tagged [protocol]

Tor has developed several internal protocols, like the rendezvous specification, directory specification etc. This tag is for questions which deal with protocols Tor uses.

59
votes
1answer
26k views

How do onion addresses exactly work?

I understand that the .onion address is a public key of sorts, but not much more than that (I can vaguely guess, though). When nobody knows the IP of the .onion address, how do requests reach it? Are ...
40
votes
3answers
44k views

How does Tor route DNS requests?

Tor can only handle TCP connections, but DNS is a UDP protocol. How does Tor route DNS requests over its TCP based network? Why can the same approach not be used to route all UDP traffic over Tor?
19
votes
1answer
6k views

Is it possible to look up the public key for a .onion-address?

I know .onion addresses are a (partial) hash of a descriptor which contains a public RSA key, so I was wondering: it is possible to see the public key that is found when connecting to a .onion hidden ...
3
votes
2answers
2k views

What happens with TCP connections on SIGNAL NEWNYM?

When I send the NEWNYM command tor will build new circuits. I'm wondering what happens with open TCP connections. Will tor wait a certain timeout to give them a chance to close, or do I break those ...
2
votes
1answer
297 views

Usage and purpose of variable-length cells?

The Tor protocol version 1 uses 512-byte cells to obfuscate traffic patterns: Traffic flowing down the circuit is sent in fixed-size ``cells'', which are unwrapped by a symmetric key at each node ...
6
votes
2answers
1k views

What is the reasoning behind keeping hidden service onion RSA keys at 1024 length?

Is the cost to performance of using larger key length not cost effective? How would it negatively impact anyone if some hosts decided to use a larger key length (i.e. Why isn't anyone free to manually ...
3
votes
1answer
307 views

Signal NEWNYM vs Stream isolation

Resources. This answer explains well what happens at NEWNYM request, and I also dig into the code, yet my lack of knowledge on low level networking prevents me to make a proper design decision if ...
20
votes
1answer
15k views

.onion Domains DNS lookup

How does Tor resolve .onion Domains? Are there also some central DNS servers in the Tor network that store these records? Is there a chance that two hidden services generate the same domain name?
4
votes
3answers
2k views

Can tor nodes (entry, exit, others) store IPs?

I'm a new Tor user. And I want to ensure several questions. Can "entry point" router store my IP? Can "middle relay" store "entry point" IP? Can "exit point" router store "middle relay" IP? I think ...
4
votes
1answer
285 views

What is the risk of guard relay and exit relay being one and the same?

Looking at the circuits build for a client during a Tor process, I have noticed the following: Four circuits were built. On the first circuit the guard node was a1. On the second circuit the exit ...
3
votes
1answer
1k views

How does it work - “Hidden services”?

Could somebody describe to me, like for Nooo-oo-ob, from the Start and to the complete End. My questions are: I've setup HS. My Tor client connect to the rendezvous. Is it populate full onion ...
2
votes
2answers
121 views

Does Tor add encryption at the TCP protocol level?

Just wondering if http://www.tcpcrypt.org/ would be useful to add? Also is there any work being done to replace/add encryption at the ODI level?
7
votes
3answers
3k views

Where is the Tor API documentation?

I want to have a program I'm writing interact with the Internet exclusively through Tor. After perusing the Tor project's documentation it appears that they do not specify the API anywhere i.e. how a ...
6
votes
2answers
826 views

Are Tor Hidden Service Addresses private by default?

If I want to configure a Hidden Service but only for personal use and didn't give out its hostname/.onion address to anyone. Can its address still be crawled/known to any third party? Summary: If no ...
2
votes
1answer
252 views

How is Path Selection done in Tor?

Can anybody explain how path selection is done in Tor because the man page fail to specify in detail on how certain probabilities are calculated etc. In the man page there are a set of equations: ...
1
vote
1answer
142 views

Clearing the client side DNS cache provides privacy improvement?

Context. In my quest on figuring out if I must use NEWNYM signal or stream isolation is enough for me I dig into the code and narrowed down the possible privacy improvements that NEWNYM can bring over ...
1
vote
1answer
49 views

Clearing the state of rendezvous client provides privacy improvement?

Context. In my quest on figuring out if I must use NEWNYM signal or stream isolation is enough for me I dig into the code and narrowed down the possible privacy improvements that NEWNYM can bring over ...