Security Considerations for Passkey-Based Web3 Wallets

This report examines the security model of Passkey-based Web3 wallets (WebAuthn/FIDO2) end-to-end: where keys live (device-bound vs. synced), how a UserOperation is hashed, signed, encoded, and validated on-chain, and how historical vulnerabilities (signature verification bugs, hardware side-channels, WebAuthn API compromises, challenge-binding and recovery failures) map onto each stage of the lifecycle; it concludes with concrete audit and implementation checks for registration, signing, on-chain validation, account-abstraction interactions, sync/recovery, and infrastructure to reduce the risk of unauthorized on-chain asset transfers.