From: Luke Dashjr <luke@dashjr.org>
To: lightning-dev@lists.linuxfoundation.org
Date: Tue, 3 Jul 2018 12:13:44 +0000
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Cc: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] [Lightning-dev]  BIP sighash_noinput
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On Monday 02 July 2018 18:11:54 Gregory Maxwell wrote:
> I know it seems kind of silly, but I think it's somewhat important
> that the formal name of this flag is something like
> "SIGHASH_REPLAY_VULNERABLE" or likewise or at least
> "SIGHASH_WEAK_REPLAYABLE". This is because noinput is materially
> insecure for traditional applications where a third party might pay to
> an address a second time, and should only be used in special protocols
> which make that kind of mistake unlikely. 

I don't agree. Address reuse is undefined behaviour. Nobody should assume it 
is safe or works.

I intend to possibly use SIGHASH_NOINPUT for ordinary Bitcoin transactions in 
a wallet I am writing, which explicitly does not support address reuse.

Luke