Asylia
A Bitcoin multisig vault with hardware signing
Overview
My own Bitcoin management product: the browser prepares a transaction, and Trezor and Ledger hardware wallets sign it. My work covers product design, critical UX and the website.
Scope
- Product design and custody model
- Signing flow and wallet interface
- Public website
01 /Context
Asylia is my Bitcoin multisig vault. Control over funds is distributed across multiple hardware signers, and a transaction requires a predefined number of signatures.
The product combines hardware signing, a clear policy and portable recovery data. What a person understands before signing matters to me just as much as the technology.
02 /Problem
Multisig adds more devices, signatures and steps to using a wallet. The interface must explain what a person is signing and what still needs to be done.
The transaction’s intent, impact and signature status therefore need to be clear before the hardware receives a request.
03 /My role and responsibilities
I designed the product, critical user journeys and website. My work connects the custody model with what a person sees when preparing a transaction, signing and recovering access.
04 /Constraints and risks
- The private key must never pass through the browser or server. The browser may only construct an unsigned PSBT; signing happens exclusively on the device.
- Recovery data must be portable so that access to funds does not depend on a single application.
05 /Key decisions
Clarity before signing
The intent, impact and signature status are visible before the hardware receives a request.
Keys stay on the device
The browser prepares a PSBT. Private keys remain on the Trezor or Ledger, where the signature is created.
Portable recovery data
Descriptors, signers and recovery data can be transferred to Sparrow, Caravan or Bitcoin Core.
06 /Architecture
The browser prepares a transaction in PSBT format for hardware devices to sign. The policy determines the required number of signatures. Descriptors and recovery data allow the vault to be used with other supported tools.
07 /UX
My design focused on the transaction’s intent, impact and the status of each signature. The interface should help a person understand the next step before taking it.
08 /Technology
Bitcoin multisig, PSBT, Output descriptors, Trezor, Ledger
09 /Outcome
Asylia brings together a multisig vault, hardware signing with Trezor and Ledger, and portable recovery data. The public website presents the product and its approach to the user interface.