Re: [Tails-dev] Persistent guard nodes on DVD boot

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Autore: sajolida
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To: The Tails public development discussion list, carrybean
Oggetto: Re: [Tails-dev] Persistent guard nodes on DVD boot
Robert Ransom:
> On 12/3/13, Carribbean Rob <carrybean@???> wrote:
>> Hi,
>>
>> I believe that one of the drawbacks of Tails, when compared to other
>> privacy focused distributions, is that the entry nodes change each boot
>> when using a DVD. This is fine if the IP address that someone is
>> connecting to Tor from also changes but in some scenarios this may not be
>> the case. As the Tor Blog outlines in a recent post, changing entry nodes
>> each boot can become a security risk over time [1].
>>
>> I have been thinking about how to improve this situation while also
>> preserving the non-persistent nature of booting Tails from a DVD where
>> keeping /var/lib/tor across boots is difficult.
>>
>> Would it be possible to choose entry guards on the first boot and then use
>> the IP of the guard as a seed for a 4 word passphrase, maybe XOR'd with a
>> PIN to increase the search space? Given the small number of entry guards
>> it would be trivial to later match the supplied four word passphrase with
>> the correct bridge/PIN on the next boot. This way you would be able to
>> choose the same entry guard each boot until it goes down. When the entry
>> guard goes down, a new 4 word passphrase is generated and recorded by the
>> user. If three entry guards are used then a 12 word phrase would be output
>> where each four words would represent a bridge.
>
> Nice try, but (a) that doesn't store enough information about each
> guard, and (b) users will not cooperate. See
> <https://bugs.torproject.org/2653> for the real fix.


Hi Robert,

I didn't find your reply very encouraging :(

Finding a good way to support entry guards in Tails is a tricky issue.
Unfortunately, this goal is too far on our roadmap [1] for the core devs
to have time to really think about it. So we shouldn't refrain people
from brainstorming about it and I'd like to encourage new contributors
into our discussions.

The debate on the Tor trac is interesting but I don't think you can
pretend this is as being "the real fix", it looks more like an ongoing
collective debate to me. And having this debate on the Tails channels
really makes sense.

[1] https://labs.riseup.net/code/projects/tails/roadmap