Subject: Re: [p2prg] P2P: goals & prospects?

From: Arnaud Legout <[email-masked]>
Date: Thu, 05 Aug 2010 19:12:16 +0200

On 25/07/2010 09:29, Ivan Shmakov wrote:
>
> 	• the anonymity is somewhat easier to implement.

this is one frequent misunderstanding of the P2P architecture.
If you really work in P2P, it means that you expose your IP address to
any other peer.
One common mistake is to believe that it is safer to expose your IP address
(and all your behavior) to a random peer than to a central server. The 
rational
is that it is supposed to be hard to get information on one specific peer.
Unfortunately (for privacy) it is wrong. It is easy for any peer without 
any dedicated
infrastructure to collect a huge amount of information.
planete.inria.fr/bluebear

Regards,
Arnaud.

---

From: Ivan Shmakov <[email-masked]>
Date: Fri, 6 Aug 2010 08:06:22 +0000

>>>>> On 8/5/10, Arnaud Legout <[email-masked]> wrote:

 >> Б─╒ the anonymity is somewhat easier to implement.

 > this is one frequent misunderstanding of the P2P architecture.

        Thanks for the comment and the pointer!

 > If you really work in P2P, it means that you expose your IP address
 > to any other peer.

        Right.  However, the “intent” of the given agent's participation
        is not necessarily exposed when a system such as, say, Freenet
        is considered.

        With Freenet, IIUC, while one's intent to download or upload
        some particular content is exposed, it is not known in advance
        whether the downloading (uploading) peer acts for itself, or on
        behalf of some third party.

        Apparently, Tor works similarly.

 > One common mistake is to believe that it is safer to expose your IP
 > address (and all your behavior) to a random peer than to a central
 > server. The rational is that it is supposed to be hard to get
 > information on one specific peer.

 > Unfortunately (for privacy) it is wrong. It is easy for any peer
 > without any dedicated infrastructure to collect a huge amount of
 > information.

        I've got it.  The idea is that since one necessarily exposes its
        download requests to (potentially) the whole torrent, it will
        thus expose it to the attacker (as long as there's one in the
        torrent) as well, right?

 > planete.inria.fr/bluebear

        Nice.  I was also quite disturbed by the rather light-headed
        approach to security over Tor, though I've never imagined this
        particular Tor + BitTorrent combination.

---

From: Wes Felter <[email-masked]>
Date: Fri, 06 Aug 2010 13:15:39 -0500

>          Apparently, Tor works similarly.

Freenet and Tor provide anonymity only because they are specifically 
designed to provide anonymity, not because they are P2P. In general, P2P 
does not intrinsically provide anonymity and often hurts it.

Wes Felter

---

From: Ivan Shmakov <[email-masked]>
Date: Sat, 07 Aug 2010 14:12:39 +0700

>>>>> Wes Felter writes:
>>>>> Arnaud Legout writes:
>>>>> Ivan Shmakov writes:

 >>>> (These points preasumably attract interest to the problem from the
 >>>> libertarians' and other such groups.)

 >> With Freenet, IIUC, while one's intent to download or upload some
 >> particular content is exposed, it is not known in advance whether
 >> the downloading (uploading) peer acts for itself, or on behalf of
 >> some third party.

 > designed to provide anonymity, not because they are P2P.

	The question is: could anonymity be provided by a
	specifically-designed system that is not P2P?

	Any “proxy” technique will expose the IP's of the users, both to
	the service administrators, and the transit ISP's; subject to
	easier data harvesting and banning.

 > In general, P2P does not intrinsically provide anonymity and often
 > hurts it.

	Is it due to that for P2P users the “one user per IP” relation
	works better, while (due to RFC 1918, NAT and proxies) it seems
	to mostly fail for the rest of the users nowadays? (though I
	don't have any numbers at hand.)

-- 
FSF associate member #7257

---

From: Arnaud Legout <[email-masked]>
Date: Sat, 07 Aug 2010 11:30:49 +0200

>          thus expose it to the attacker (as long as there's one in the

right, but when you consider that it is easy (we did it from a single 
machine) to monitor
in almost real time (every 30 minutes) all public torrents, it means 
that you cannot
assume any privacy in torrents.
Here again, I want to stress that it has never been a designed goal of 
BitTorrent, but
a feature assumed by users. Indeed, users assume that the high popularity
and the distributed nature of a P2P system provide some kind of privacy. 
One goal
in the bluebear project is to show that this is wrong.

Regards,
Arnaud.

---

From: Ivan Shmakov <[email-masked]>
Date: Sat, 07 Aug 2010 23:04:07 +0700

>>>>> Arnaud Legout <[email-masked]> writes:

 >> download requests to (potentially) the whole torrent, it will thus
 >> expose it to the attacker (as long as there's one in the torrent) as
 >> well, right?

 > machine) to monitor in almost real time (every 30 minutes) all public
 > torrents, it means that you cannot assume any privacy in torrents.

	Well, yes, it's an impressive research, to my mind.  A thing
	that I'm likely to relate to my students.

	I'm not sure on how you can map the IP addresses to persons,
	however, in the presence of NAT (on IPv4) and those “privacy
	friendly” IPv6 addresses that one's likely to find on Windows?

PS.  I'll print the papers as soon as my brother will get the printer up
	and working.

[…]

---

From: Ivan Shmakov <[email-masked]>
Date: Sun, 08 Aug 2010 17:10:10 +0700

>>>>> Giorgio Zoppi <[email-masked]> writes:

 >> * Towards P2P computing

 >> There're currently a number of on-line resources that perform
 >> various kind of data processing for casual users. Say, it may be the
 >> conversion of a document to PDF or DjVu. There're apparently some
 >> interest in hosting geospatial data processing services for the
 >> benefit of those users that aren't themselves technically fluent
 >> enough to deploy these at their own hardware.

 >> IIUC, the approach is envisioned by its proponents as a
 >> “conventional”, non-P2P system.

 >> But let us imagine that there're a number of centers that perform
 >> various kinds of data processing. Then, there're may also be some
 >> data processing software at the user's side. Could we imagine a
 >> system that, given a user's request for a certain “target” dataset,
 >> will calculate the path for the data from the place (or one of the
 >> places, since we assume that P2P filesharing is used) it's located
 >> to the user's host, with the intermediate peers performing the
 >> relevant data processing steps?

 > Yep, but can think in computing using p2p for doing high-availability
 > services:).

(mode 'thinks-aloud)

	This way, the reliability may be achieved through replication of
	the revelant software on the nodes.

	Actually, what surprises me in the “centralized administration”
	(even if the service itself is distributed) proposals is that
	they can easily fail should there be a peak in the number of
	active users.  Or they can fail should there be a connectivity
	failure.

	“Hey, I was preparing my tomorrow's report, but the Internet has
	suddenly failed.”

(mode 'sorry-for-the-buzz)