I’m seeking conceptual and technical feedback on a draft BIP for Stateless PSBT Coordination, designed to solve the communication gap in multisig setups without relying on trusted, stateful servers.
Currently, coordinating a multisig transaction across hardware and software wallets requires either manual file passing (USB/SD) or relying on a centralized coordinator server that logs IP addresses, xpubs, and transaction metadata.
The Proposed Standard: I’ve drafted a BIP (bip-stateless-psbt-coordination) that proposes a “Blind Relay” model. It leverages an ephemeral, end-to-end encrypted WebSocket architecture.
Zero-Knowledge: The relay server never sees the PSBT, the xpubs, or the signatures.
Stateless: The room and all associated data cease to exist the moment the room is closed or after 24hours.
Split-Key OpSec: The room URL and decryption key (#key fragment) are transported out-of-band by the users.
Implementation (Signing Room): To prove the viability of this BIP, I’ve built an open-source reference implementation called Signing Room. I just released v1.8.0, which enforces human-layer OpSec by actively separating the transport of the room link and the decryption key in the UI.
Feedback Request: I would love the community’s eyes on:
I have just realised v2.0.0 of signing room which has alot of great improvements and also has a drop in web component so anyone can integrate with one Html Tag.
This release decouples the core cryptographic and coordination logic from our main Angular client. It is a framework-agnostic TypeScript SDK designed to programmatically orchestrate ephemeral, end-to-end encrypted PSBT coordination ceremonies.
Because the SDK is unified with our standard web UI, all programmatic room creations, joins, and signature uploads sync dynamically in real-time. This opens up the possibility for headless multisig automation, such as AI agent signing ceremonies combined with a human-in-the-loop coordinator who retains finalization privileges.
Key areas covered in the walkthrough:
The architectural components and how the fit together for signing room
Sean Carlin ·