From: Andrew Chow <achow101-lists@achow101•com>
To: Jonathan Underwood <junderwood@bitcoinbank•co.jp>,
Bitcoin Protocol Discussion
<bitcoin-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] BIP174 amendment proposal (Important Signer Check should be mentioned)
Date: Tue, 09 Jul 2019 20:26:45 +0000 [thread overview]
Message-ID: <cimBiAqniTMJ06jVVlflC_H15_eDo7hDkdcwrxK84-4IBKJIFaKr2c6NJCev85v633R-xcGQ9w0csmQMF0Zzq6Zr83uj2gDB2oWS531MKaM=@achow101.com> (raw)
In-Reply-To: <CAMpN3mLtKXoFerZnpM_qs-CS6fjJFzmPS5+Ri0j27YwRmqam-A@mail.gmail.com>
[-- Attachment #1: Type: text/plain, Size: 1473 bytes --]
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
[-- Attachment #2: Type: text/html, Size: 3176 bytes --]
next prev parent reply other threads:[~2019-07-09 20:36 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 [this message]
2019-07-09 22:21 ` Jonathan Underwood
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='cimBiAqniTMJ06jVVlflC_H15_eDo7hDkdcwrxK84-4IBKJIFaKr2c6NJCev85v633R-xcGQ9w0csmQMF0Zzq6Zr83uj2gDB2oWS531MKaM=@achow101.com' \
--to=achow101-lists@achow101$(echo .)com \
--cc=bitcoin-dev@lists$(echo .)linuxfoundation.org \
--cc=junderwood@bitcoinbank$(echo .)co.jp \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox