How do credential revocation mechanisms work in privacy-preserving digital ID systems? It's a fascinating piece of the zkID puzzle. The challenge is revoking access or credentials while maintaining privacy—you need to invalidate an ID without exposing which specific credential holder got revoked. Different approaches handle this trade-off in various ways, from on-chain revocation registries to zero-knowledge proofs that prove non-revocation status. The mechanics get intricate fast, but they're critical for building digital identity infrastructure that doesn't sacrifice user privacy at the altar of security. Worth diving deeper into how these systems actually balance privacy, security, and usability when tokens or credentials need to be pulled back.