From: Jonathan Underwood <junderwood@bitcoinbank•co.jp>
To: Andrew Chow <achow101-lists@achow101•com>
Cc: Bitcoin development mailing list <bitcoin-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] BIP174 amendment proposal (Important Signer Check should be mentioned)
Date: Wed, 10 Jul 2019 07:21:25 +0900 [thread overview]
Message-ID: <CAMpN3mJ1qz0XZjHqBzEYNVe0d+YXV18VtMsxqn4D5gt45diZdg@mail.gmail.com> (raw)
In-Reply-To: <cimBiAqniTMJ06jVVlflC_H15_eDo7hDkdcwrxK84-4IBKJIFaKr2c6NJCev85v633R-xcGQ9w0csmQMF0Zzq6Zr83uj2gDB2oWS531MKaM=@achow101.com>
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Hi Andrew,
Ok, I will go ahead and write the amendment and make a PR.
Thanks!
Jon
2019年7月10日(水) 5:26 Andrew Chow <achow101-lists@achow101•com>:
> This was the original intent of the sighash field. Either the sighash is
> acceptable to the signer and the signer signs with it, or they do not sign
> at all.
>
> On 7/9/19 11:58 AM, Jonathan Underwood via bitcoin-dev wrote:
>
> Hi all,
>
> Just to be brief, I'll kick off with an attack scenario.
>
> 1. I am a signer, I get a PSBT that is ready to sign. I parse. I sign
> according to the PSBT as-is.
> 2. I notice my UTXO was stolen by a hacker because they changed my PSBT
> input's sighashtype to SIGHASH_ANYONECANPAY | SIGHASH_NONE and after the
> fact they changed the outputs to send to themselves, and added an input
> they signed with SIGHASH_ALL.
> 3. I lose the BTC in my UTXO.
>
> So we should definitely add to the signer checks "ensure the sighash type
> given is the type of sighash you want to sign." etc.
>
> My proposal for a wording change would be addition to the bullet list:
>
> - If a sighash type is provided, the signer MUST check that the sighash
> type is acceptable to them, and fail signing if unacceptable.
> - If a sighash type is not provided, the signer SHOULD sign using
> SIGHASH_ALL, but may sign with any sighash type they wish.
>
> Any thoughts?
>
> Thanks,
> Jon
>
> --
> -----------------
> Jonathan Underwood
> ビットバンク社 チーフビットコインオフィサー
> -----------------
>
> 暗号化したメッセージをお送りの方は下記の公開鍵をご利用下さい。
>
> 指紋: 0xCE5EA9476DE7D3E45EBC3FDAD998682F3590FEA3
>
>
>
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prev parent reply other threads:[~2019-07-09 22:21 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-09 15:58 Jonathan Underwood
2019-07-09 20:26 ` Andrew Chow
2019-07-09 22:21 ` Jonathan Underwood [this message]
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