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Re: [tor-talk] Better Privacy for Tor Node Operators

----- Original Message ----
> From: tagnaq <tagnaq@xxxxxxxxx>
> To: tor-talk@xxxxxxxxxxxxxxxxxxxx
> Sent: Mon, April 25, 2011 2:24:07 AM
> Subject: Re: [tor-talk] Better Privacy for Tor Node Operators
> Alice  runs an non-exit Tor node at home. The Tor node at home is always
> running.  Her ISP assigns her a new IP address every day.
> On 2011-01-29 Alice  decides to create a new example.com account
> (alice@xxxxxxxxxxx) using her home IP address  - the same as her Tor node
> is using [] . (Alice is not using Tor  for browsing the web
> but she uses Torbutton in Transparent mode - I'm just  mentioning this to
> make clear that beside the IP address there is not much  identifying
> information)
> On 2011-03-13 (and several IP's) later Alice  (now browsing with
> []) wants another example.com account and  again visits their
> website. The Tor node is still running. example.com would  like to know
> if Alice did already create an account in the  past.
> example.com performs the following steps to answer its  question:
> 1. IP address to Tor node fingerprint lookup
> 2. fetch all IP  addresses that the Tor node (gathered in step 1) ever had
> (one of the  obtained records is: 2011-01-29
> 3. look for matching IP  addresses (comparing list gathered in step 2
> with their own  database)
> MATCH: 2011-01-29 => created: alice@xxxxxxxxxxx
> Now example.com  will kindly ask Alice if she lost her password for
> alice@xxxxxxxxxxx ;)

Is it plausible that a group of people could be NATed together with a node 
operator? How does limiting node data eliminate the problem of an IP address 
match? Isn't this more a problem of historical data being publicly available 
ad-hoc? Where is it kept? Is there a need or good use for it? (Yes, of course 
would-be attackers could maintain their own lists.)

If one doesn't want to use Tor to visit example.com, maybe a non-blocked one-hop 
proxy would work. I don't know how to solve the bigger problem of IP address 
linking without using a remote proxy.

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