[tor-dev] WTF-PAD and the future

[teor]

> On 29 Jul 2018, at 23:42, George Kadianakis <desnacked at riseup.net> wrote:
> 
>>> 2) From what I understand you are also hoping to use WTF-PAD to protect
>>>   against circuit fingerprinting and not just website
>>>   fingerprinting. They told me that while this might be plausible,
>>>   there is no current research on how well it can achieve that.  Are we
>>>   hoping to do that? And what research remains here? How can I help?
>>>   Which parts of the Tor circuit protocol are we hoping to hide?
>> 
>> I am designing WTF-PAD to be a framework for deploying padding against
>> arbitrary traffic analysis attacks. It is meant to allow us to define
>> histograms on the fly (in the Tor consensus) as these are studied. The
>> fact that they have not yet been studied is not super relevant to
>> deploying the framework for it now.
>> 
> 
> ACK.
> 
> What other traffic analysis attacks are we looking at addressing here?
> 
> I'm thinking of stuff like "circuit fingerprinting of onion services",
> but I wonder if histograms and random sampling is too crude to actually
> be able to help against sophisticated attacks. I don't have a suggestion
> for something better currently.
> 
> On that topic, is it decided whether the adaptive padding of WTF-PAD
> will also happen during circuit construction, or only after that?

Padding during circuit construction should work with VPADDING cells:
https://gitweb.torproject.org/torspec.git/tree/tor-spec.txt#n508

At least it did last time I checked:
https://github.com/teor2345/endosome/blob/master/client-or-22929.py
https://trac.torproject.org/projects/tor/ticket/22929

We should avoid using PADDING cells during the handshake, because Tor
sometimes closes the connection:
https://github.com/teor2345/endosome/blob/master/client-or-22934.py

T

--
teor

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