[Cryptography] Updates on Durov charges in France

[efc at disroot.org]

On Fri, 6 Sep 2024, Peter Fairbrother wrote:

>> I had no idea! If NSA can crack Tor at will, how come so few people
>> using Tor get caught? Is it that they "save" this weapon for serious
>> cases only?
>
> It might be so. It might be simpler, they just don't want to deal with a
> gazillion lesser agencies.
>
> Or even simpler yet, helping police forces isn't part of their mission.
> US intelligence agencies yes, police forces no.
>
> No Such Agency, yes?

You do have a point.

>> And when it comes to the people who do got caught, usually
>> you read about them leaking their name or some kind of traceable
>> information somewhere, or that their web site has a bug or something,
>> but you never hear about NSA lending a helping hand.
>
> You never hear about the NSA lending a helping hand anyway, at least
> until it's all over. You shouldn't expect them to, if everyone knows a
> (cracked) system is cracked then they won't use it.

I also heard that what is common practice is to trade jobs with foreign
agencies, to circumvent legal restrictions against spying on ones own
population.

> But as to whether they can crack Tor at will, yes, a global passive
> adversary undoubtedly can. Even the TOR people will tell you that. It
> isn't something which should surprise anyone.

I usually consider Tor fine for "regular" use cases. And with regular I
mean if you want privacy, but are not in conflict with the government.
That means you are such "small fry" that no one will bother with you.

> As to relevant research - eg google "tor global passive adversary" and
> you will find plenty.

Thank you, plenty of information there.

> One way it works is fairly simple, NSA looks at traffic from a known
> source to an entry node, finds traffic which matches the sizes and
> timings of the packets from that node to a second node, repeat for
> second node, repeat for third node, rinse and done.
>
> It's very simple, *IF* you can view internet traffic to your hearts
> content - which is where the global passive bit comes in.  Ever wonder
> why some internet routes go through the US or UK even if neither party
> is in either country?

Wouldn't it be trivial to protect against size by just adding some
random payload?

When it comes to timing attacks...

> If you can only see some traffic then it gets a bit statistical, but
> long-term everyone is screwed. You can control a few nodes.

... a yes, I thought it would become statistical. I imagine that there
could be added delays in the network, but that would reduce usability.

> Or, as there are only 1,837 entry/exit nodes (I might be a bit out of
> date here), so survey a goodly subset of them (no compromising needed,
> just see their I/O traffic) and don't bother with the nodes in between.
>
> Eventually they get used by the traffic you want to deanonymise.

What about setting up your own entry nodes to make sure that
you don't risk connecting to one under government control? Of course
that raises the question of how to setup one anonymously yourself, and
if you can do that, why not use the node for your activities right away,
but I always thought that adding one of your own might mitigate the
problem somewhat.

Best regards, 
Daniel


>
> When tracing .onions you can use easy-to-detect packet sizes and timings.
>
>
> Peter Fairbrother
>
>
>
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