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Date: Tue, 21 Nov 2017 23:10:28 +1000
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Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
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Subject: Re: [bitcoin-dev] Why SegWit Anyway?
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There is incentive because of artificially distorted block weight rules. It
is favourable for a miner to choose a segwit tx over a non segwit tx as
they can fit more of them into a block and earn more fees.
On Nov 21, 2017 11:06 PM, "Dan Bryant via bitcoin-dev" <
bitcoin-dev@lists.linuxfoundation.org> wrote:
> Is there any incentive for miners to pick segwit transactions over
> non-segwit transaction. Do they require less, equal, or more compute to
> process?
>
> On Nov 20, 2017 11:46 AM, "Johnson Lau via bitcoin-dev" <
> bitcoin-dev@lists.linuxfoundation.org> wrote:
>
> We can=E2=80=99t =E2=80=9Cjust compute the Transaction ID the same way th=
e hash for
> signing the transaction is computed=E2=80=9D because with different SIGHA=
SH flags,
> there are 6 (actually 256) ways to hash a transaction.
>
> Also, changing the definition of TxID is a hardfork change, i.e. everyone
> are required to upgrade or a chain split will happen.
>
> It is possible to use =E2=80=9Cnormalised TxID=E2=80=9D (BIP140) to fix m=
alleability
> issue. As a softfork, BIP140 doesn=E2=80=99t change the definition of TxI=
D.
> Instead, the normalised txid (i.e. txid with scriptSig removed) is used
> when making signature. Comparing with segwit (BIP141), BIP140 does not ha=
ve
> the side-effect of block size increase, and doesn=E2=80=99t provide any i=
ncentive
> to control the size of UTXO set. Also, BIP140 makes the UTXO set
> permanently bigger, as the database needs to store both txid and normalis=
ed
> txid
>
> On 21 Nov 2017, at 1:24 AM, Praveen Baratam via bitcoin-dev <
> bitcoin-dev@lists.linuxfoundation.org> wrote:
>
> Bitcoin Noob here. Please forgive my ignorance.
>
> From what I understand, in SegWit, the transaction needs to be serialized
> into a data structure that is different from the current one where
> signatures are separated from the rest of the transaction data.
>
> Why change the format at all? Why cant we just compute the Transaction ID
> the same way the hash for signing the transaction is computed?
>
> --
> Dr. Praveen Baratam
>
> about.me <http://about.me/praveen.baratam>
> _______________________________________________
>
> 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
>
>
>
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev@lists.linuxfoundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>
>
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<div dir=3D"auto">There is incentive because of artificially distorted bloc=
k weight rules. It is favourable for a miner to choose a segwit tx over a n=
on segwit tx as they can fit more of them into a block and earn more fees.<=
/div><div class=3D"gmail_extra"><br><div class=3D"gmail_quote">On Nov 21, 2=
017 11:06 PM, "Dan Bryant via bitcoin-dev" <<a href=3D"mailto:=
bitcoin-dev@lists.linuxfoundation.org">bitcoin-dev@lists.linuxfoundation.or=
g</a>> wrote:<br type=3D"attribution"><blockquote class=3D"gmail_quote" =
style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><di=
v dir=3D"auto">Is there any incentive for miners to pick segwit transaction=
s over non-segwit transaction.=C2=A0 Do they require less, equal, or more c=
ompute to process?</div><div class=3D"gmail_extra"><br><div class=3D"gmail_=
quote">On Nov 20, 2017 11:46 AM, "Johnson Lau via bitcoin-dev" &l=
t;<a href=3D"mailto:bitcoin-dev@lists.linuxfoundation.org" target=3D"_blank=
">bitcoin-dev@lists.<wbr>linuxfoundation.org</a>> wrote:<br type=3D"attr=
ibution"><blockquote class=3D"m_-6431831756956729977quote" style=3D"margin:=
0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style=3D"word-=
wrap:break-word;line-break:after-white-space"><div>We can=E2=80=99t =E2=80=
=9Cjust compute the Transaction ID the same way the hash for signing the tr=
ansaction is computed=E2=80=9D because with different SIGHASH flags, there =
are 6 (actually 256) ways to hash a transaction.</div><div><br></div><div>A=
lso, changing the definition of TxID is a hardfork change, i.e. everyone ar=
e required to upgrade or a chain split will happen.</div><div><br></div>It =
is possible to use =E2=80=9Cnormalised TxID=E2=80=9D (BIP140) to fix mallea=
bility issue. As a softfork, BIP140 doesn=E2=80=99t change the definition o=
f TxID. Instead, the normalised txid (i.e. txid with scriptSig removed) is =
used when making signature. Comparing with segwit (BIP141), BIP140 does not=
have the side-effect of block size increase, and doesn=E2=80=99t provide a=
ny incentive to control the size of UTXO set. Also, BIP140 makes the UTXO s=
et permanently bigger, as the database needs to store both txid and normali=
sed txid<br><div><div><br><blockquote type=3D"cite"><div class=3D"m_-643183=
1756956729977elided-text"><div>On 21 Nov 2017, at 1:24 AM, Praveen Baratam =
via bitcoin-dev <<a href=3D"mailto:bitcoin-dev@lists.linuxfoundation.org=
" target=3D"_blank">bitcoin-dev@lists.linuxfounda<wbr>tion.org</a>> wrot=
e:</div><br class=3D"m_-6431831756956729977m_-2919472362485226639Apple-inte=
rchange-newline"></div><div><div class=3D"m_-6431831756956729977elided-text=
"><div dir=3D"ltr"><div><span style=3D"font-family:Verdana,arial,sans-serif=
;font-size:14px">Bitcoin Noob here. Please forgive my ignorance.</span></di=
v><span style=3D"font-family:Verdana,arial,sans-serif;font-size:14px"><div>=
<span style=3D"font-family:Verdana,arial,sans-serif;font-size:14px"><br></s=
pan></div>From what I understand, in SegWit, the transaction needs to be se=
rialized into a data structure that is different from the current one where=
signatures are separated from the rest of the transaction data.</span><div=
><span style=3D"font-family:Verdana,arial,sans-serif;font-size:14px"><br></=
span></div><div><span style=3D"font-family:Verdana,arial,sans-serif;font-si=
ze:14px">Why change the format at all? Why cant we just compute the Transac=
tion ID the same way the hash for signing the transaction is computed?</spa=
n><br clear=3D"all"><div><br></div>-- <br><div class=3D"m_-6431831756956729=
977m_-2919472362485226639gmail_signature"><div style=3D"color:rgb(34,34,34)=
;font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,2=
55)">Dr. Praveen Baratam</div><div style=3D"color:rgb(34,34,34);font-family=
:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)"><br></d=
iv><div style=3D"color:rgb(34,34,34);font-family:arial,sans-serif;font-size=
:13px;background-color:rgb(255,255,255)"><a href=3D"http://about.me/praveen=
.baratam" style=3D"color:rgb(17,85,204)" target=3D"_blank">about.me</a></di=
v></div>
</div></div></div>
______________________________<wbr>_________________<div class=3D"m_-643183=
1756956729977quoted-text"><br>bitcoin-dev mailing list<br><a href=3D"mailto=
:bitcoin-dev@lists.linuxfoundation.org" target=3D"_blank">bitcoin-dev@lists=
.linuxfoundat<wbr>ion.org</a><br><a href=3D"https://lists.linuxfoundation.o=
rg/mailman/listinfo/bitcoin-dev" target=3D"_blank">https://lists.linuxfound=
ation.<wbr>org/mailman/listinfo/bitcoin-d<wbr>ev</a><br></div></div></block=
quote></div><br></div></div><br>______________________________<wbr>________=
_________<br>
bitcoin-dev mailing list<br>
<a href=3D"mailto:bitcoin-dev@lists.linuxfoundation.org" target=3D"_blank">=
bitcoin-dev@lists.linuxfoundat<wbr>ion.org</a><br>
<a href=3D"https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev" =
rel=3D"noreferrer" target=3D"_blank">https://lists.linuxfoundation.<wbr>org=
/mailman/listinfo/bitcoin-d<wbr>ev</a><br>
<br></blockquote></div><br></div>
<br>______________________________<wbr>_________________<br>
bitcoin-dev mailing list<br>
<a href=3D"mailto:bitcoin-dev@lists.linuxfoundation.org">bitcoin-dev@lists.=
<wbr>linuxfoundation.org</a><br>
<a href=3D"https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev" =
rel=3D"noreferrer" target=3D"_blank">https://lists.linuxfoundation.<wbr>org=
/mailman/listinfo/bitcoin-<wbr>dev</a><br>
<br></blockquote></div></div>
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