MIME-Version: 1.0
References: <5B6756D0-6BEF-4A01-BDB8-52C646916E29@friedenbach.org>
 <C623794E-F061-4C7A-B05D-378798ED2BF7@friedenbach.org>
 <201709190309.08669.luke@dashjr.org>
 <CAA2B000-6C54-4AD7-B931-43C99D615A61@friedenbach.org>
 <CAKzdR-phAarTY16BOnC95BPN0qMNEE_XZ9H-XmFeeaBc2V1U5w@mail.gmail.com>
 <3385CE20-C1BA-40DD-8FC3-8F53F3350717@friedenbach.org>
 <CAKzdR-pnvystx5H+P+OCXm73aVmWdyesCymerSgx=pCuXx+YGA@mail.gmail.com>
 <9FD4AF03-28A5-4B8A-9C12-CBCB1BC2E22C@friedenbach.org>
 <CAKzdR-r6u4J+_T5X516A=-tLWZ8zFFFsRokReiJndDE_S64OqQ@mail.gmail.com>
 <CAPg+sBi+WnzpJkcG6XACdpqqz9ZA3rHX8+H9b5eExUdgXaeiWQ@mail.gmail.com>
 <CAJowKg+kbnExgKt7H8GD6Kc-iLJEOvZhtw0uVbophhLCszvOHg@mail.gmail.com>
In-Reply-To: <CAJowKg+kbnExgKt7H8GD6Kc-iLJEOvZhtw0uVbophhLCszvOHg@mail.gmail.com>
From: "Russell O'Connor" <roconnor@blockstream.com>
Date: Fri, 9 Apr 2021 07:39:45 -0400
Message-ID: <CAMZUoKmQyV67dhWS_+t1CmqNYT490_7g3WwKgxB-jiYfje+F+Q@mail.gmail.com>
To: Erik Aronesty <erik@q32.com>, 
 Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Content-Type: multipart/alternative; boundary="0000000000008e839205bf889f5b"
Subject: Re: [bitcoin-dev] maximum block height on transaction
Precedence: list

--0000000000008e839205bf889f5b
Content-Type: text/plain; charset="UTF-8"

From https://bitcointalk.org/index.php?topic=1786.msg22119#msg22119:

We can't safely do OP_BLOCKNUMBER.  In the event of a block chain reorg
> after a segmentation, transactions need to be able to get into the chain in
> a later block.  The OP_BLOCKNUMBER transaction and all its dependants would
> become invalid.  This wouldn't be fair to later owners of the coins who
> weren't involved in the time limited transaction.
>
> nTimeLock does the reverse.  It's an open transaction that can be replaced
> with new versions until the deadline.  It can't be recorded until it
> locks.  The highest version when the deadline hits gets recorded.  It could
> be used, for example, to write an escrow transaction that will
> automatically permanently lock and go through unless it is revoked before
> the deadline.  The feature isn't enabled or used yet, but the support is
> there so it could be implemented later.
>

Unfortunately, limiting the maximum block height for a specific transaction
would have exactly the same problem as cited above for OP_BLOCKNUMBER.

On Fri, Apr 9, 2021 at 7:21 AM Erik Aronesty via bitcoin-dev <
bitcoin-dev@lists.linuxfoundation.org> wrote:

> is there any way to specify a maximum block height on a transaction?
>
> ie: this tx is only valid if included in a block with a certain height or
> less
>
> i feel like this would be useful
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev@lists.linuxfoundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>

--0000000000008e839205bf889f5b
Content-Type: text/html; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

<div dir=3D"ltr"><div>From <a href=3D"https://bitcointalk.org/index.php?top=
ic=3D1786.msg22119#msg22119">https://bitcointalk.org/index.php?topic=3D1786=
.msg22119#msg22119</a>:</div><div><br></div><blockquote class=3D"gmail_quot=
e" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204)=
;padding-left:1ex"><div>We can&#39;t safely do OP_BLOCKNUMBER.=C2=A0 In the=
 event of a block chain reorg after a segmentation, transactions need to be=
 able to get into the chain in a later block.=C2=A0 The OP_BLOCKNUMBER tran=
saction and all its dependants would become invalid.=C2=A0 This wouldn&#39;=
t be fair to later owners of the coins who weren&#39;t involved in the time=
 limited transaction.<br><br>nTimeLock does the reverse.=C2=A0 It&#39;s an =
open transaction that can be replaced with new versions until the deadline.=
=C2=A0 It can&#39;t be recorded until it locks.=C2=A0 The highest version w=
hen the deadline hits gets recorded.=C2=A0 It could be used, for example, t=
o write an escrow transaction that will automatically permanently lock and =
go through unless it is revoked before the deadline.=C2=A0 The feature isn&=
#39;t enabled or used yet, but the support is there so it could be implemen=
ted later.</div></blockquote><div><br></div><div>Unfortunately, limiting th=
e maximum block height for a specific transaction would have exactly the sa=
me problem as cited above for OP_BLOCKNUMBER.<br></div><br><div class=3D"gm=
ail_quote"><div dir=3D"ltr" class=3D"gmail_attr">On Fri, Apr 9, 2021 at 7:2=
1 AM Erik Aronesty via bitcoin-dev &lt;<a href=3D"mailto:bitcoin-dev@lists.=
linuxfoundation.org">bitcoin-dev@lists.linuxfoundation.org</a>&gt; wrote:<b=
r></div><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex=
;border-left:1px solid rgb(204,204,204);padding-left:1ex">is there any way =
to specify a maximum block height on a transaction?<br>
<br>
ie: this tx is only valid if included in a block with a certain height or l=
ess<br>
<br>
i feel like this would be useful<br>
_______________________________________________<br>
bitcoin-dev mailing list<br>
<a href=3D"mailto:bitcoin-dev@lists.linuxfoundation.org" target=3D"_blank">=
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>
</blockquote></div></div>

--0000000000008e839205bf889f5b--