My guests today are James McComish and Peter Ferguson, co-founders of Forum. Forum is an iPhone app where every groupDM has its own shared wallet.

James and Peter are among the most knowledgeable builders working with WebAuthn and Passkeys that I've encountered. On this episode, we discuss the ins-and-outs of WebAuthn in production, including largeBlob, cross origin domains, session keys, and the three versions of the spec to date. We also delve into the team's journey building Forum.

It was a treat talking to James and Peter about their experience building with Passkeys. I hope you enjoy the show.

While Forum is fundraising, as always, this show is provided as entertainment and does not constitute legal, financial, or tax advice or any form of endorsement or suggestion. Crypto has risks and you alone are responsible for doing your research and making your own decisions.

Links

• Hosted by @nnnnicholas
• Forum
• WebAuthn Explainer W3C
• ERC-4337
• ERC-137
• Stackup account abstraction SDKs
• ERC-6900: Modular Smart Contract Accounts and Plugins
• Secure Payment Confirmation
• WebAuthn W3C
• WebAuthn MDN
• CanIUse WebAuthn
• Chrome's WebAuthn support

Chapters

(00:00:00) Intro (00:01:25) How Forum got started (00:06:10) Passkeys and Account Abstraction (00:12:00) WebAuthn: User Agents, Relaying parties, and Users (00:16:30) Cross origin (00:20:30) largeBlob (00:29:30) iCloud recovery (00:32:00) Passkeys as Smart Wallet Signers and secp256r1 onchain (00:35:00) largeBlob revisited: k1 private keys and cross device sync (00:43:34) Cross-domain Passkeys (00:48:00) Secure Payments Confirmation: Sign arbitrary data with Passkeys and native API (00:57:20) Session keys (01:02:00) ERC-4337’s design (01:09:00) Upgrading AA wallets (01:09:55) ERC-6900 Modular AA accounts (01:12:45) Key rotation with AA (01:13:25) Permissions: MPC and AA solutions (01:15:25) Cross-chain state & AA permissions (01:19:45) Consolidation of Paymasters and Sequencers (01:20:58) The Forum app (01:26:00) Onboarding in Forum (01:28:00) How to get into the Testflight (01:30:10) Where Forum is going next (01:33:00) The Belfast dev scene (01:33:45) Where to learn more (01:34:30) Outro