PassSeeds – hijacking Passkeys to unlock new cryptographic use cases

4 months ago

Passkeys provide secure, cryptographic authentication for website/app logins, but their use is restricted to this purpose.
PassSeeds is a novel approach that repurposes passkeys' properties for broader cryptographic use cases by treating the passkey’s public key as seed material.
PassSeeds enable deterministic key generation for various cryptographic applications, including Bitcoin transactions, decentralized social media, and zero-knowledge proofs.
The PassSeed mechanism involves generating a passkey, recovering its public key via ECDSA key recovery from two signatures, and converting it into a BIP-39 mnemonic phrase for backup.
PassSeeds offer a user-friendly alternative to traditional cryptographic key management, leveraging the security and sync capabilities of passkeys.
The implementation includes TypeScript methods for creating, retrieving, and converting PassSeeds, with a focus on security and usability.
PassSeeds can serve as a polyfill for WebAuthn's PRF feature, enabling deterministic cryptographic operations across all browsers.
A demo and NPM package are available for integrating PassSeeds into web applications.

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