Exploring iCloud Keychain Security and Passkeys in Crypto Custody

My guests today are DC Posch and Nalin Bhardwaj, co-founders of Daimo. Daimo is a stablecoin focused iOS wallet built with Passkeys and AA Smart Accounts. On this episode, DC, Nalin, and I discuss their new p256Verifier contract, which is an audited Solidity implementation of p256r1 verification. We discuss the ins-and-outs of gas optimized onchain p256 verification, compare their contract to the FreshCryptoLib implementation, and consider the limitations of precomputation. We cover EIP-7212, which DC and Nalin co-authored alongside the team from Clave, and discuss Daimo's exciting proposal for progressive precompiles, also known as precompile shadowing, which would allow precompiles to elegantly replace the p256Verifier, on chains where it is adopted. It was fantastic learning from DC and Nalin who are experts working at the intersection of WebAuthn cryptography and blockchain. I hope you enjoy the show. 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. If you value Web3 Galaxy Brain and would like to support the show, please send me a tweet or DM saying why you listen and what makes Web3 Galaxy Brain special for you. I'll post the best testimonies to the show's website. Thank you! Links

• Hosted by @nnnnicholas
• Sign up for the Daimo beta
• Daimo
• Daimo Github
• DC Posch
• Nalin Bhardwaj
• EthUniversity
• Hack Lodge
• Solidity Summit
• p256Verifier and Github and Daimo's blog
• Progressive precompiles (aka Precompile shadowing)
• FreshCryptoLib
• WebAuthn Halo2
• WebAuthn Circom
• ZK Sync Era's p256 precompile
• Awesome WebAuthn
• Dogan_Eth's State of Verifying p256
• Veridise audit

Chapters

(00:00:00) Intro

(00:01:37) How DC and Nalin met: EthUniversity and Hack Lodge (00:03:40) Decentralization and permissionlessness

(00:05:57) What is Daimo

(00:08:30) Advantages of Smart Contract Accounts

(00:12:55) Passkeys and Enclave Keys

(00:16:25) Trusted execution environments and firmware updates (00:19:55) Apple binaries and reproducible APKs

(00:24:30) Self-custody UX

(00:25:58) Why p256 (secp256r1)?

(00:28:20) ECDSA vs ZK

(00:31:10) Renaud Dubois & FreshCryptoLib’s p256 implementation vs Daimo’s p256Verifier

(00:36:50) Wycheproof test vectors

(00:38:00) CPU style optimization for EVM cryptography (00:39:40) Precomputation, or not

(00:44:10) EIP-7212

(00:49:05) Progressive Precompiles (aka Precompile shadowing) (00:54:00) EVM equivalence and p256

(01:00:05) Veridise audit

(01:02:00) Daimo's forthcoming Base64 encoder

(01:03:40) Daimo cross-chain stablecoin wallets

(01:06:00) Getting Daimo