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From: Johnson Lau <jl2012@xbt.hk>
To: bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org>
Subject: [bitcoin-dev] Disallow insecure use of SIGHASH_SINGLE
Date: Fri, 1 Jun 2018 02:53:01 +0800	[thread overview]
Message-ID: <9FC9FA73-9572-48AF-9590-68F0D298D6A0@xbt.hk> (raw)

I’ve made a PR to add a new policy to disallow using SIGHASH_SINGLE without matched output:

https://github.com/bitcoin/bitcoin/pull/13360

Signature of this form is insecure, as it commits to no output while users might think it commits to one. It is even worse in non-segwit scripts, which is effectively SIGHASH_NOINPUT|SIGHASH_NONE, so any UTXO of the same key could be stolen. (It’s restricted to only one UTXO in segwit, but it’s still like a SIGHASH_NONE.)

This is one of the earliest unintended consensus behavior. Since these signatures are inherently unsafe, I think it does no harm to disable this unintended “feature” with a softfork. But since these signatures are currently allowed, the first step is to make them non-standard.


             reply	other threads:[~2018-05-31 18:53 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-31 18:53 Johnson Lau [this message]
2018-06-06  0:17 ` [bitcoin-dev] Disallow insecure use of SIGHASH_SINGLE Chris Stewart
2018-06-06  0:43   ` Peter Todd
2018-06-06  0:49 ` Peter Todd

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