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Date: Tue, 5 Aug 2014 21:01:29 +0300
Message-ID: <CAE28kUQwHwkovAVhp=OHfOw72n2NRqQgDWjWqNkp8RrJY9d_0A@mail.gmail.com>
From: Alex Mizrahi <alex.mizrahi@gmail.com>
To: Gregory Maxwell <gmaxwell@gmail.com>, 
	Bitcoin Dev <bitcoin-development@lists.sourceforge.net>
Content-Type: multipart/alternative; boundary=089e0158bab41d8ca504ffe5a559
Subject: Re: [Bitcoin-development] deterministic transaction expiration
Precedence: list

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>
> A distinction there is that they can only become invalid via a
> conflict=E2=80=94 replaced by another transaction authored by the prior
> signers. If no other transaction could be created (e.g. you're a
> multisigner and won't sign it again) then there is no such risk.


You need to check transaction's dependencies up to a certain depth to know
whether it is safe:
 If one of inputs depends on transaction which is signed by parties with
unknown trustworthiness, then it isn't safe.


>  It now introduces chance events ("act of god") into the mix where they
> they didn't exist before.


You need to check transaction's dependencies up to a certain depth to know
whether it is safe:
  If one of inputs depends on transaction time-locked script (or other
unrecognized script), then it isn't safe.

Situation is identical, you might need several extra lines of code.

I think it would matter only if we had deterministic, reliable mempool and
reorganization behavior. But it's not something we can depend on.

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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:0 0 0 .8ex;border-left:1px #c=
cc solid;padding-left:1ex">A distinction there is that they can only become=
 invalid via a<br>

conflict=E2=80=94 replaced by another transaction authored by the prior<br>
signers. If no other transaction could be created (e.g. you&#39;re a<br>
multisigner and won&#39;t sign it again) then there is no such risk.</block=
quote><div><br></div><div>You need to check transaction&#39;s dependencies =
up to a certain depth to know whether it is safe:</div><div>=C2=A0If one of=
 inputs depends on transaction which is signed by parties with unknown trus=
tworthiness, then it isn&#39;t safe.</div>
<div>=C2=A0<br></div><blockquote class=3D"gmail_quote" style=3D"margin:0 0 =
0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> =C2=A0It=C2=A0now intr=
oduces chance events (&quot;act of god&quot;) into the mix where they<br>
they didn&#39;t exist before.</blockquote><div><br></div><div>You need to c=
heck transaction&#39;s dependencies up to a certain depth to know whether i=
t is safe:</div><div>=C2=A0 If one of inputs depends on transaction time-lo=
cked script (or other unrecognized script), then it isn&#39;t safe.</div>
<div><br></div><div>Situation is identical, you might need several extra li=
nes of code.</div><div><br></div><div>I think it would matter only if we ha=
d deterministic, reliable mempool and reorganization behavior. But it&#39;s=
 not something we can depend on.</div>
<div><br></div></div></div></div>

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