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Date: Mon, 18 Aug 2014 19:35:00 +0200
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From: Pieter Wuille <pieter.wuille@gmail.com>
To: Gregory Maxwell <gmaxwell@gmail.com>
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Cc: Ivan Pustogarov <ivan.pustogarov@uni.lu>,
	Bitcoin Dev <bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] Outbound connections rotation
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Yes, I believe peer rotation is useful, but not for privacy - just for
improving the network's internal knowledge.

I haven't looked at the implementation yet, but how I imagined it would be
every X minutes you attempt a new outgoing connection, even if you're
already at the outbound limit. Then, if a connection attempt succeeds,
another connection (according to some scoring system) is replaced by it.
Given such a mechanism, plus reasonable assurances that better connections
survive for a longer time, I have no problem with rotating every few
minutes.
On Aug 18, 2014 7:23 PM, "Gregory Maxwell" <gmaxwell@gmail.com> wrote:

> On Mon, Aug 18, 2014 at 9:46 AM, Ivan Pustogarov <ivan.pustogarov@uni.lu>
> wrote:
> > Hi there,
> > I'd like to start a discussion on periodic rotation of outbound
> connections.
> > E.g. every 2-10 minutes an outbound connections is dropped and replaced
> > by a new one.
>
> Connection rotation would be fine for improving a node's knoweldge
> about available peers and making the network stronger against
> partitioning.
>
> I haven't implemented this because I think your motivation is
> _precisely_ opposite the behavior. If you keep a constant set of
> outbound peers only those peers learn the origin of your transactions,
> and so it is unlikely that any particular attacker will gain strong
> evidence. If you rotate where you send out your transactions then with
> very high probability a sybil pretending to be many nodes will observe
> you transmitting directly.
>
> Ultimately, since the traffic is clear text, if you expect to have any
> privacy at all in your broadcasts you should be broadcasting over tor
> or i2p.
>
>
> ------------------------------------------------------------------------------
> _______________________________________________
> Bitcoin-development mailing list
> Bitcoin-development@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/bitcoin-development
>

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<p dir=3D"ltr">Yes, I believe peer rotation is useful, but not for privacy =
- just for improving the network&#39;s internal knowledge.</p>
<p dir=3D"ltr">I haven&#39;t looked at the implementation yet, but how I im=
agined it would be every X minutes you attempt a new outgoing connection, e=
ven if you&#39;re already at the outbound limit. Then, if a connection atte=
mpt succeeds, another connection (according to some scoring system) is repl=
aced by it. Given such a mechanism, plus reasonable assurances that better =
connections survive for a longer time, I have no problem with rotating ever=
y few minutes.<br>
</p>
<div class=3D"gmail_quote">On Aug 18, 2014 7:23 PM, &quot;Gregory Maxwell&q=
uot; &lt;<a href=3D"mailto:gmaxwell@gmail.com">gmaxwell@gmail.com</a>&gt; w=
rote:<br type=3D"attribution"><blockquote class=3D"gmail_quote" style=3D"ma=
rgin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
On Mon, Aug 18, 2014 at 9:46 AM, Ivan Pustogarov &lt;<a href=3D"mailto:ivan=
.pustogarov@uni.lu">ivan.pustogarov@uni.lu</a>&gt; wrote:<br>
&gt; Hi there,<br>
&gt; I&#39;d like to start a discussion on periodic rotation of outbound co=
nnections.<br>
&gt; E.g. every 2-10 minutes an outbound connections is dropped and replace=
d<br>
&gt; by a new one.<br>
<br>
Connection rotation would be fine for improving a node&#39;s knoweldge<br>
about available peers and making the network stronger against<br>
partitioning.<br>
<br>
I haven&#39;t implemented this because I think your motivation is<br>
_precisely_ opposite the behavior. If you keep a constant set of<br>
outbound peers only those peers learn the origin of your transactions,<br>
and so it is unlikely that any particular attacker will gain strong<br>
evidence. If you rotate where you send out your transactions then with<br>
very high probability a sybil pretending to be many nodes will observe<br>
you transmitting directly.<br>
<br>
Ultimately, since the traffic is clear text, if you expect to have any<br>
privacy at all in your broadcasts you should be broadcasting over tor<br>
or i2p.<br>
<br>
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</blockquote></div>

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