Subject: Re: [bitcoin-dev] Proposal: Bitcoin Secure Multisig Setup

From: Hugo Nguyen <[email-masked]>
Date: Tue, 9 Feb 2021 02:05:54 -0800

Hi Christopher,
Comments inline.

On Tue, Feb 9, 2021 at 1:31 AM Christopher Allen <
[email-masked]> wrote:

> In the Airgapped Wallet Community we also have been investigating
> solutions, in particular as current common practice is is reuse the same
> xpub for all multisigs, for instance [90081696/48'/0'/0'/2']
> xpub6DYLEkDfCdHzh5FHGHDJksQvFqu6kYANa1sfo6fA8n5ZWkSwyCRVVzyq9LY2eNGB6T9BKDeGJp2ZarjRZHd7WB95nSaFEDhFMK6zSV6D49b
>
>
I don't think reusing XPUBs inside different multisig wallets is a good
idea... For starters, loss of privacy in one wallet will immediately affect
privacy of other wallets. I think multisig wallets should be completely
firewalled from each other. That means one unique XPUB per wallet. This is
what we have been doing with the Nunchuk wallet.

> We’ve also have been looking into multi round commitment scheme, but
> wanted to align the UX so that it would work like to musig for users.
> Discussion on it is scattered, for instance
>
> https://github.com/BlockchainCommons/Airgapped-Wallet-Community/discussions/16#discussioncomment-212013
>
> Nothing got as far as your version though.
>
> So Concept ACK from Blockchain Commons. Less clear on your specifics
> though. We will review.
>
> Note that we are releasing a descriptor & multisig centric iOS and Android
> reference wallet soon so solving this correctly and having interoperability
> with others is very important for our roadmap.
>

Thank you and good to know ! Look forward to solving this correctly as well.

Best,

Hugo

> — Christopher Allen