From rusty at rustcorp.com.au  Fri Jul 13 00:04:14 2018
From: rusty at rustcorp.com.au (Rusty Russell)
Date: Fri, 13 Jul 2018 09:34:14 +0930
Subject: [Lightning-dev] [bitcoin-dev] BIP sighash_noinput
In-Reply-To: <CAK_c0Xo0G9-YiOGZK_8WsYNkzjQRaH+u7XOUAozKosggXeXTNg@mail.gmail.com>
References: <871sewirni.fsf@gmail.com>
	<CAAS2fgS-_D7aBcDf_nAbuREBxv65zYMr60-1YqCnx-esvRVfEg@mail.gmail.com>
	<201807031213.51127.luke@dashjr.org>
	<CAK_c0Xo0G9-YiOGZK_8WsYNkzjQRaH+u7XOUAozKosggXeXTNg@mail.gmail.com>
Message-ID: <878t6gxapt.fsf@rustcorp.com.au>

DING FENG <dingfeng12345 at gmail.com> writes:
> Hi,
>
> I'm a junior developer and a bitcoin user.
> And I have read this thread carefully.
>
> I'm very worried about "SIGHASH_NOINPUT".
>
> Because "SIGHASH_NOINPUT" looks will be widely used, and it makes reuse
> address more dangerous.

No.

A wallet should *never* create a SIGHASH_NOINPUT to spend its own UTXOs.
SIGHASH_NOINPUT is useful for smart contracts which have unique
conditions, such as a pair of peers rotating keys according to an agreed
schedule (eg. lightning).

Cheers,
Rusty.