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From: Jannes Faber <jannes.faber@gmail.com>
Date: Sat, 12 Dec 2015 01:43:11 +0100
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To: Bitcoin Dev <bitcoin-dev@lists.linuxfoundation.org>
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Subject: Re: [bitcoin-dev] Segregated Witness features wish list
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Segregated IBLT

I was just wondering if it would make sense when we have SW to also make
Segregated IBLT? Segregating transactions from signatures and then tune the
parameters such that transactions have a slightly higher guarantee and save
a bit of space on the signatures side.

IBLT should of course, most of the time, convey all transactions _and_ all
signatures. However, in suboptimal situations, at least the receiving miner
will be more likely to have all the transactions, just possibly not all the
signatures.

Assuming the miner was already planning on SPV mining anyway, at least now
she knows which transactions to remove from her mempool, taking away an
excuse to mine an empty block. And she can still verify most of the
signatures too (whatever % could be recovered from the IBLT).

I guess this does not improve the worst adversarial case for IBLT block
propagation, but it should improve the effectiveness in cases where the
"normal" IBLT would fail to deliver all transactions. Transactions without
signatures is better than no transactions at all, for a miner that's eager
to start on the next block, right? In "optimal" cases it would reduce the
size of the IBLT.

Sorry if this was already suggested.


--
Jannes

On 10 December 2015 at 13:54, Tamas Blummer via bitcoin-dev <
bitcoin-dev@lists.linuxfoundation.org> wrote:

> Note that the unused space in coin base input script allows us to
> soft-fork an additional SW Merkle tree root into the design,
> therefore please make sure the new SW data structure also has a new slot
> for future extension.
>
> Tamas Blummer
>
> _______________________________________________
> 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"><div><div>Segregated IBLT<br><br>I was just wondering if i=
t would make sense when we have SW to also make Segregated IBLT? Segregatin=
g transactions from signatures and then tune the parameters such that trans=
actions have a slightly higher guarantee and save a bit of space on the sig=
natures side.<br><br></div>IBLT should of course, most of the time, convey =
all transactions _and_ all signatures. However, in suboptimal situations, a=
t least the receiving miner will be more likely to have all the transaction=
s, just possibly not all the signatures.<br><br></div>Assuming the miner wa=
s already planning on SPV mining anyway, at least now she knows which trans=
actions to remove from her mempool, taking away an excuse to mine an empty =
block. And she can still verify most of the signatures too (whatever % coul=
d be recovered from the IBLT).<br><div><br></div><div>I guess this does not=
 improve the worst adversarial case for IBLT block propagation, but it shou=
ld improve the effectiveness in cases where the &quot;normal&quot; IBLT wou=
ld fail to deliver all transactions. Transactions without signatures is bet=
ter than no transactions at all, for a miner that&#39;s eager to start on t=
he next block, right? In &quot;optimal&quot; cases it would reduce the size=
 of the IBLT.<br></div><div><br></div><div>Sorry if this was already sugges=
ted.<br></div><div><br></div></div><div class=3D"gmail_extra"><br clear=3D"=
all"><div><div class=3D"gmail_signature">--<br>Jannes</div></div>
<br><div class=3D"gmail_quote">On 10 December 2015 at 13:54, Tamas Blummer =
via bitcoin-dev <span dir=3D"ltr">&lt;<a href=3D"mailto:bitcoin-dev@lists.l=
inuxfoundation.org" target=3D"_blank">bitcoin-dev@lists.linuxfoundation.org=
</a>&gt;</span> wrote:<br><blockquote class=3D"gmail_quote" style=3D"margin=
:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Note that the unus=
ed space in coin base input script allows us to soft-fork an additional SW =
Merkle tree root into the design,<br>
therefore please make sure the new SW data structure also has a new slot fo=
r future extension.<br>
<br>
Tamas Blummer<br>
<div class=3D"HOEnZb"><div class=3D"h5"><br>
_______________________________________________<br>
bitcoin-dev mailing list<br>
<a href=3D"mailto:bitcoin-dev@lists.linuxfoundation.org">bitcoin-dev@lists.=
linuxfoundation.org</a><br>
<a href=3D"https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev" =
rel=3D"noreferrer" target=3D"_blank">https://lists.linuxfoundation.org/mail=
man/listinfo/bitcoin-dev</a><br>
</div></div></blockquote></div><br></div>

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