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I am trying to optimize the Orchid Tor client library for my needs and noticed that every connection with every node uses TLS with turned off certificate verification.

Actually there are no TLS certificates on any Tor nodes, so it seems to be useless; is it?

Can I turn it off to improve network speed?

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  • 3
    To start with, security things aside, aren't you bound by the Tor protocol? Generally, this sort of thing isn't mix-and-match; you must follow the protocol the way everyone else does, or else your client can't interoperate with anyone else.
    – cpast
    Commented Dec 15, 2014 at 4:53
  • Actually we are experimenting about optimizing tor and may be later make propose for better performance. And i think that i can create modified "enter nodes" for my applications for better performance, this is not as secure as general way of working, but later whet there are will be more optimized nodes it may be secure enough.
    – ex3ndr
    Commented Dec 15, 2014 at 5:28
  • Do you value speed over privacy and security?
    – curiousguy
    Commented Dec 15, 2014 at 5:39
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    No, it is not useless, unverified TLS can be cracked only by man-in-the-middle attack which is not always possible for an attacker (for example, the most known government watching box at the network providers can only hear and don't alter packet).
    – peterh
    Commented Dec 15, 2014 at 13:46
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    Take a look at this blog post: Facebook, hidden services, and https certs
    – user63550
    Commented Dec 15, 2014 at 16:39

1 Answer 1

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When you are browsing TOR hidden services, the TOR system already provides end-to-end encryption, so another TLS layer is redundant. It is in fact counter-productive, because one of the goals of TLS is to de-anonymize the server. It makes no sense to go through the trouble to set up a hidden service and then get a certificate from a certificate authority which tells the whole world who you are. Well, you could use a self-signed certificate (some people seem to do this, otherwise Orchid wouldn't explicitly disable verification), but a certificate not signed by a certificate authority can be replaced by a man-in-the-middle so it only provides protection from a passive eavesdropper.

However, when you browse normal websites via TOR, TLS is even more important than usual, because the exit node can eavesdrop on your traffic in cleartext and even manipulate it. There were already exit nodes spotted in the wild which exploit this by inserting advertising or even malware into websites their users browse or to sniff logins for popular websites. Using TLS makes this impossible, but only when used correctly (which means with certificate validation. An unvalidated certificate could be from the malicious exit node).

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  • Facebook points their Tor node to their load balancer, which is IN FRONT of their SSL terminator, likely outsourced on partially untrusted networks. For their situation, SSL over Tor adds security as it allows them to keep their current DDoS protection and filtering intact.
    – Natanael
    Commented Dec 15, 2014 at 14:32
  • @Natanael The facebookcorewwwi.onion hidden service is a useless gimmick. It provides no practical use whatsoever, not for facebook and not for their users. It is not a useful example for how to use TOR.
    – Philipp
    Commented Dec 15, 2014 at 14:53
  • I am not talking about hidden services or normal websites. I am talking about commuinication between nodes that already encrypted by TOR itself and then encrypted with TLS with disabled verification.
    – ex3ndr
    Commented Dec 16, 2014 at 5:54
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    @ex3ndr in that case TLS is also redundant. A prerequisite for TLS is a central certificate authority which properly verifies the identity of everyone with a certificate. Take that out and the whole system breaks down.
    – Philipp
    Commented Dec 16, 2014 at 8:31

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