From: "'Sean Carlin' via Bitcoin Development Mailing List" <bitcoindev@googlegroups.com>
To: Bitcoin Development Mailing List <bitcoindev@googlegroups.com>
Subject: Re: [bitcoindev] [BIP Draft] Blind Relay: Stateless Encrypted WebSocket Coordination for PSBTs
Date: Thu, 26 Mar 2026 09:19:42 -0700 (PDT) [thread overview]
Message-ID: <b6af2c43-1bde-4f64-a2aa-42d948b9a1fen@googlegroups.com> (raw)
In-Reply-To: <fede50f58f286763106ba143e7530990eb7d86c1.camel@pythcoiner.dev>
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Hi Pyth,
That is a fair point regarding Bitcoin Core's existing dependencies. I
chose AES-GCM-256 specifically because this BIP targets Application Layer
coordination, with a focus on cross-platform ubiquity (Web PWAs, Mobile,
and Desktop).
For these environments, AES-GCM is a core primitive of the Web Crypto API,
meaning it is implemented natively and audited by browser/OS vendors.
Standardizing on ChaCha20-Poly1305 would force web and mobile developers to
bundle external, unoptimized JavaScript cryptographic libraries. In the
context of a browser-based or mobile coordinator, I believe relying on
native, hardware-accelerated OS primitives provides a smaller and more
secure attack surface than importing third-party JS dependencies.
If the protocol were strictly node-to-node (Transport Layer), I would agree
on ChaCha20. But for client-to-relay coordination, the Web Crypto API
support makes AES-GCM the safer choice for the average user's device in my
opinion.
Happy to discuss further if you see a reason why supporting ChaCha20 is a
benefit other than ecosystem alignment.
I updated the BIPs rationale section with this earlier today.
All the best,
Sean Carlin
On Thursday, 26 March 2026 at 14:21:27 UTC pyth wrote:
> Hi Sean, this is interesting, but note that bitcoin core doesn't have
> dependencies for AES-GCM-256, while it have dependencies for CHACHA20-
> POLY1305.
>
> Best,
> Pyth
>
> On Wed, 2026-03-25 at 05:00 -0700, 'Sean Carlin' via Bitcoin
> Development Mailing List wrote:
> > Hi everyone,
> >
> > I'd like to propose a new BIP for real-time, trust-minimized
> > coordination of multi-signature PSBTs.
> >
> > The Problem
> > Coordinating N-of-M Bitcoin transactions currently forces users into
> > a binary choice:
> > - Manual out-of-band transfers (USB drives, secure messengers) that
> > preserve privacy but introduce high friction and error risk, or
> > - Stateful coordination servers that offer good UX but act as privacy
> > honeypots, logging metadata, signer relationships, and often storing
> > PSBTs on disk.
> >
> > The Proposal: Blind Relay
> > This BIP introduces a "Blind Relay" - an ephemeral, stateless, zero-
> > knowledge WebSocket relay. All payloads are encrypted client-side
> > with AES-GCM-256, with decryption keys held exclusively in client-
> > side URL fragments (never sent to the server). The relay operates
> > entirely in RAM with a strict 24-hour TTL and self-destructs upon
> > completion, providing real-time coordination without persistent
> > metadata or disk storage.
> >
> > A reference implementation has been running in production for three
> > months, successfully facilitating real multisig ceremonies.
> >
> > Links
> > - BIP Draft:
> >
> https://github.com/scarlin90/bip-stateless-psbt-coordination/blob/main/bip-draft.md
> > - Source Code: https://github.com/scarlin90/signingroom
> > - Live Client: https://signingroom.io
> > - Related Research Paper: https://arxiv.org/abs/2601.17875
> >
> > I look forward to your technical feedback - especially on the
> > specification, security model, edge cases, and any suggested
> > improvements.
> >
> > Best regards,
> > Sean Carlin
> > --
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> >
> https://groups.google.com/d/msgid/bitcoindev/3f1a1491-06e1-4453-9538-fa66bc432a06n%40googlegroups.com
> > .
>
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next prev parent reply other threads:[~2026-03-26 18:07 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-25 12:00 'Sean Carlin' via Bitcoin Development Mailing List
2026-03-26 0:15 ` pyth
2026-03-26 16:19 ` 'Sean Carlin' via Bitcoin Development Mailing List [this message]
2026-03-26 14:02 ` [bitcoindev] " Thomas Suau
2026-03-26 16:02 ` 'Sean Carlin' via Bitcoin Development Mailing List
2026-04-03 11:03 ` 'Sean Carlin' via Bitcoin Development Mailing List
2026-04-06 20:12 ` STEVEN SLATER
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