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From: Jim Posen <jim.posen@gmail.com>
Date: Sat, 14 Apr 2018 12:46:01 -0700
Message-ID: <CADZtCSgQ-R8Z-eCPNaaNgSP6FWNn6qOucWUX3WkuOFHmXNc5dQ@mail.gmail.com>
To: Christian Decker <decker.christian@gmail.com>
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Cc: Bitcoin development mailing list <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] BloomFilter issue with segwit addresses
Precedence: list

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To Christian's point about privacy, I'll take this opportunity to
shamelessly review beg on https://github.com/bitcoin/bitcoin/pull/12254,
the PR for BIP 158 implementation (but not 157).

On Sat, Apr 14, 2018 at 9:14 AM, Christian Decker <
decker.christian@gmail.com> wrote:

> Note that this would compound the privacy leak that Jonas Nick used to
> identify address clusters via the bloom filters in one of his publication=
s.
> By reducing the false positives when matching you can get very detailed
> clusters. Then again we know that bloom filters aren't good for privacy
> anyway, so this might be a non-issue.
>
> On Sat, Apr 14, 2018, 00:17 Jim Posen via bitcoin-dev <bitcoin-dev@lists.
> linuxfoundation.org> wrote:
>
>> Why not add the outpoints owned by the wallet to the filter and watch fo=
r
>> those instead of elements in the input script or witness data?
>>
>> On Fri, Apr 13, 2018 at 12:12 PM, Jonas Schnelli via bitcoin-dev <
>> bitcoin-dev@lists.linuxfoundation.org> wrote:
>>
>>> Hi Andreas
>>>
>>> Thanks for bringing this up and this seems indeed to be suboptimal.
>>>
>>> > I wonder if Bitcoin Core would be willing to extend the BIP37 matchin=
g
>>> > rules such that data elements in the witness are also matched against=
?
>>>
>>> Bitcoin Core is not an identity that can be =E2=80=9Ewilling to extend=
=E2=80=9C (or
>>> reject) a feature.
>>> Someone needs to come up with a proposal (pull request).
>>>
>>> Maybe an extension for BIP37 would make sense (*meh*).
>>> Just inserting the witness data into the bloom filter seems to be an
>>> easy solution (CBloomFilter::IsRelevantAndUpdate())
>>>
>>> /jonas
>>>
>>> _______________________________________________
>>> bitcoin-dev mailing list
>>> bitcoin-dev@lists.linuxfoundation.org
>>> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>>>
>>>
>> _______________________________________________
>> bitcoin-dev mailing list
>> bitcoin-dev@lists.linuxfoundation.org
>> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>>
>

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<div dir=3D"ltr">To Christian&#39;s point about privacy, I&#39;ll take this=
 opportunity to shamelessly review beg on=C2=A0<a href=3D"https://github.co=
m/bitcoin/bitcoin/pull/12254">https://github.com/bitcoin/bitcoin/pull/12254=
</a>, the PR for BIP 158 implementation (but not 157).</div><div class=3D"g=
mail_extra"><br><div class=3D"gmail_quote">On Sat, Apr 14, 2018 at 9:14 AM,=
 Christian Decker <span dir=3D"ltr">&lt;<a href=3D"mailto:decker.christian@=
gmail.com" target=3D"_blank">decker.christian@gmail.com</a>&gt;</span> wrot=
e:<br><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-l=
eft:1px #ccc solid;padding-left:1ex"><div dir=3D"auto">Note that this would=
 compound the privacy leak that Jonas Nick used to identify address cluster=
s via the bloom filters in one of his publications. By reducing the false p=
ositives when matching you can get very detailed clusters. Then again we kn=
ow that bloom filters aren&#39;t good for privacy anyway, so this might be =
a non-issue.</div><div class=3D"HOEnZb"><div class=3D"h5"><br><div class=3D=
"gmail_quote"><div dir=3D"ltr">On Sat, Apr 14, 2018, 00:17 Jim Posen via bi=
tcoin-dev &lt;<a href=3D"mailto:bitcoin-dev@lists.linuxfoundation.org" targ=
et=3D"_blank">bitcoin-dev@lists.<wbr>linuxfoundation.org</a>&gt; wrote:<br>=
</div><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-l=
eft:1px #ccc solid;padding-left:1ex"><div dir=3D"ltr">Why not add the outpo=
ints owned by the wallet to the filter and watch for those instead of eleme=
nts in the input script or witness data?</div><div class=3D"gmail_extra"><b=
r><div class=3D"gmail_quote">On Fri, Apr 13, 2018 at 12:12 PM, Jonas Schnel=
li via bitcoin-dev <span dir=3D"ltr">&lt;<a href=3D"mailto:bitcoin-dev@list=
s.linuxfoundation.org" rel=3D"noreferrer" target=3D"_blank">bitcoin-dev@lis=
ts.<wbr>linuxfoundation.org</a>&gt;</span> wrote:<br><blockquote class=3D"g=
mail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-l=
eft:1ex">Hi Andreas<br>
<br>
Thanks for bringing this up and this seems indeed to be suboptimal.<br>
<span><br>
&gt; I wonder if Bitcoin Core would be willing to extend the BIP37 matching=
<br>
&gt; rules such that data elements in the witness are also matched against?=
<br>
<br>
</span>Bitcoin Core is not an identity that can be =E2=80=9Ewilling to exte=
nd=E2=80=9C (or reject) a feature.<br>
Someone needs to come up with a proposal (pull request).<br>
<br>
Maybe an extension for BIP37 would make sense (*meh*).<br>
Just inserting the witness data into the bloom filter seems to be an easy s=
olution (CBloomFilter::<wbr>IsRelevantAndUpdate())<br>
<br>
/jonas<br>
<br>______________________________<wbr>_________________<br>
bitcoin-dev mailing list<br>
<a href=3D"mailto:bitcoin-dev@lists.linuxfoundation.org" rel=3D"noreferrer"=
 target=3D"_blank">bitcoin-dev@lists.<wbr>linuxfoundation.org</a><br>
<a href=3D"https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev" =
rel=3D"noreferrer noreferrer" target=3D"_blank">https://lists.linuxfoundati=
on.<wbr>org/mailman/listinfo/bitcoin-<wbr>dev</a><br>
<br></blockquote></div><br></div>
______________________________<wbr>_________________<br>
bitcoin-dev mailing list<br>
<a href=3D"mailto:bitcoin-dev@lists.linuxfoundation.org" rel=3D"noreferrer"=
 target=3D"_blank">bitcoin-dev@lists.<wbr>linuxfoundation.org</a><br>
<a href=3D"https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev" =
rel=3D"noreferrer noreferrer" target=3D"_blank">https://lists.linuxfoundati=
on.<wbr>org/mailman/listinfo/bitcoin-<wbr>dev</a><br>
</blockquote></div>
</div></div></blockquote></div><br></div>

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