Re: [bitcoin-dev] Sign / Verify message against SegWit P2SH addresses.

From: Mark Friedenbach <mark@friedenbach•org>
To: Damian Williamson <willtech@live•com.au>,
	Bitcoin Protocol Discussion
	<bitcoin-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] Sign / Verify message against SegWit P2SH addresses.
Date: Thu, 21 Dec 2017 08:29:13 -0800	[thread overview]
Message-ID: <1EE8D3E5-E9BA-4276-A139-E028D1F0BA4A@friedenbach.org> (raw)
In-Reply-To: <PS2P216MB01795FCE6D61A62EBEA79AD79D0D0@PS2P216MB0179.KORP216.PROD.OUTLOOK.COM>

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It doesn’t matter what it does under the hood. The api could be the same.

> On Dec 21, 2017, at 3:19 AM, Damian Williamson via bitcoin-dev <bitcoin-dev@lists•linuxfoundation.org> wrote:
> 
> In all seriousness, being able to sign a message is an important feature whether it is with Bitcoin Core or, with some other method. It is a good feature and it would be worthwhile IMHO to update it for SegWit addresses. I don't know about renewing it altogether, I like the current simplicity.
> 
> Regards,
> Damian Williamson
> 
> ------------------------------------
> Sometimes I like to sign a message just to verify that is what I have said.
> -
> Bitcoin: 1PMUf9aaQ41M4bgVbCAPVwAeuKvj8CwxJg
> ------------------------------------
> Signature:
> HwJPqyWF0CbdsR7x737HbNIDoRufsrMI5XYQsKZ+MrWCJ6K7imtLY00sTCmSMDigZxRuoxyYZyQUw/lL0m/MV9M=
> 
> (Of course, signed messages will verify better usually with plain text and not HTML interpreted email - need a switch for outlook.com to send plaintext.)
> From: bitcoin-dev-bounces@lists•linuxfoundation.org <bitcoin-dev-bounces@lists•linuxfoundation.org> on behalf of Mark Friedenbach via bitcoin-dev <bitcoin-dev@lists•linuxfoundation.org>
> Sent: Wednesday, 20 December 2017 8:58 AM
> To: Pavol Rusnak; Bitcoin Protocol Discussion
> Subject: Re: [bitcoin-dev] Sign / Verify message against SegWit P2SH addresses.
>  
> For what it’s worth, I think it would be quite easy to do better than the implied solution of rejiggering the message signing system to support non-P2PKH scripts. Instead, have the signature be an actual bitcoin transaction with inputs that have the script being signed. Use the salted hash of the message being signed as the FORKID as if this were a spin-off with replay protection. This accomplishes three things:
> 
> (1) This enables signing by any infrastructure out there — including hardware wallets and 2FA signing services — that have enabled support for FORKID signing, which is a wide swath of the ecosystem because of Bitcoin Cash and Bitcoin Gold.
> 
> (2) It generalizes the message signing to allow multi-party signing setups as complicated (via sighash, etc.) as those bitcoin transactions allow, using existing and future tools based on Partially Signed Bitcoin Transactions; and
> 
> (3) It unifies a single approach for message signing, proof of reserve (where the inputs are actual UTXOs), and off-chain colored coins.
> 
> There’s the issue of size efficiency, but for the single-party message signing application that can be handled by a BIP that specifies a template for constructing the pseudo-transaction and its inputs from a raw script.
> 
> Mark
> 
> > On Dec 19, 2017, at 1:36 PM, Pavol Rusnak via bitcoin-dev <bitcoin-dev@lists•linuxfoundation.org> wrote:
> > 
> > On 08/12/17 19:25, Dan Bryant via bitcoin-dev wrote:
> >> I know there are posts, and an issue opened against it, but is there
> >> anyone writing a BIP for Sign / Verify message against a SegWit address?
> > 
> > Dan, are you still planning to write this BIP?
> > 
> > -- 
> > Best Regards / S pozdravom,
> > 
> > Pavol "stick" Rusnak
> > CTO, SatoshiLabs
> > _______________________________________________
> > bitcoin-dev mailing list
> > bitcoin-dev@lists•linuxfoundation.org
> > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
> 
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