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Date: Tue, 2 Jun 2015 10:10:30 -0400
Message-ID: <CABHVRKRympU4LAeD7xG9bX3PvWMNcJaa1RMff+fukn0wSRr81A@mail.gmail.com>
From: Stephen Morse <stephencalebmorse@gmail.com>
To: Adam Back <adam@cypherspace.org>
Content-Type: multipart/alternative; boundary=001a11395ece47b21005178981c0
Cc: Bitcoin Development <bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] [BIP draft] Consensus-enforced
 transaction replacement signalled via sequence numbers
Precedence: list

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>
> That would also introduce the anomaly of a script that was once valid
> becoming later invalid, when nothing varies other than time.  That is
> not super compatible with the current model of reprocessing
> transactions in later blocks if the block they were first in gets
> reorged.
>

Very good point.


>
> (Not a huge flexibility loss as you can implement "not after" by
> making it the previous holders responsibility to spend a "not before"
> back to themselves.)
>

Do you mean something like the below?

scriptPubKey:
  IF
    {A's pub} CHECKSIGVERIFY
  ELSE
    {curr_height + 100} CLTV {B's pub} CHECKSIGVERIFY

This ensures that Alice has to spend the output in the next 100 blocks or
risk it being taken from her (she just has to put an OP_TRUE on the end of
her scriptSig). So, it seems we can forget about an inverted CLTV/CSV,
great!

Best,
Stephen

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<div dir=3D"ltr"><div class=3D"gmail_extra"><div class=3D"gmail_quote"><blo=
ckquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left=
-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;paddi=
ng-left:1ex">That would also introduce the anomaly of a script that was onc=
e valid<br>
becoming later invalid, when nothing varies other than time.=C2=A0 That is<=
br>
not super compatible with the current model of reprocessing<br>
transactions in later blocks if the block they were first in gets<br>
reorged.<br></blockquote><div><br></div><div>Very good point.=C2=A0</div><d=
iv>=C2=A0</div><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0p=
x 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-lef=
t-style:solid;padding-left:1ex">
<br>
(Not a huge flexibility loss as you can implement &quot;not after&quot; by<=
br>
making it the previous holders responsibility to spend a &quot;not before&q=
uot;<br>
back to themselves.)<br></blockquote><div><br></div><div>Do you mean someth=
ing like the below?</div><div><br></div><div><font face=3D"monospace, monos=
pace">scriptPubKey:</font><span style=3D"font-family:monospace,monospace">=
=C2=A0</span></div><div><font face=3D"monospace, monospace">=C2=A0 IF=C2=A0=
</font></div><div><span style=3D"font-family:monospace,monospace">=C2=A0 =
=C2=A0 {A&#39;s pub} CHECKSIGVERIFY</span></div><div><font face=3D"monospac=
e, monospace">=C2=A0 ELSE</font></div><div><font face=3D"monospace, monospa=
ce">=C2=A0 =C2=A0 {curr_height + 100} CLTV {B&#39;s pub} CHECKSIGVERIFY</fo=
nt></div><div><br></div><div>This ensures that Alice has to spend the outpu=
t in the next 100 blocks or risk it being taken from her (she just has to p=
ut an OP_TRUE on the end of her scriptSig). So, it seems we can forget abou=
t an inverted CLTV/CSV, great!</div><div><br></div><div>Best,<br>Stephen</d=
iv><div><br></div><div><br></div></div></div></div>

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