Zero-Knowledge Proof of Non-Revocation vs Public Revocation List

Public Revocation Lists (e.g., W3C Status List, Iden3 Reverse Hashmap) excel at simplicity and verifier cost because they store revocation status directly on a public ledger like Ethereum or Polygon. For example, a verifier can check a credential's status with a single, low-cost read operation, often for less than $0.01 on an L2 like Arbitrum. This model is battle-tested in protocols like Veramo and SpruceID, offering predictable gas fees and easy integration for applications where credential state must be universally observable.

Zero-Knowledge Proof of Non-Revocation (e.g., zk-SNARKs, Circom circuits) takes a different approach by having the credential holder generate a cryptographic proof that their credential is not on a private revocation list, without revealing the credential identifier. This results in a privacy-for-complexity trade-off. The holder bears the computational cost of proof generation (which can be 2-3 seconds on a mobile device using SnarkJS), but the verifier receives a tiny, constant-size proof (often <1 KB) that reveals nothing else, preserving holder anonymity in systems like zkPass or Sismo.

The key trade-off: If your priority is low verifier overhead, auditability, and simplicity, choose a Public Revocation List. If you prioritize holder privacy, data minimization, and off-chain verification scalability, choose ZK Proof of Non-Revocation. The former is optimal for public, compliance-heavy credentials; the latter is essential for private, user-centric identity systems.

Zero-Knowledge Proof of Non-Revocation (ZKPoNR) excels at preserving user privacy and minimizing on-chain footprint because it allows a user to cryptographically prove their credential is valid without revealing its identifier. For example, in a system like Semaphore or RLN (Rate-Limiting Nullifier), a single proof can attest to non-revocation while keeping the user's identity and transaction graph completely hidden, a critical feature for private voting or anonymous airdrops.

Public Revocation Lists (e.g., on-chain registries) take a different approach by publishing a simple, verifiable list of revoked credential identifiers. This results in superior verifier simplicity and lower computational overhead for checking status, as seen in W3C Verifiable Credentials using Ethereum or Solana as a public registry. The trade-off is a complete loss of privacy for revoked users and growing on-chain storage costs as the list expands.

The key trade-off is between privacy and operational simplicity. If your priority is maximal user anonymity, scalable off-chain verification, and compliance with regulations like GDPR's right to be forgotten, choose ZKPoNR. This is ideal for privacy-preserving DeFi, anonymous credentials, and zero-knowledge KYC. If you prioritize verifier ease-of-implementation, minimal proof generation latency, and a transparent, auditable revocation process, choose a Public Revocation List. This suits applications like public certificate transparency, open attestation systems, or scenarios where user pseudonymity is acceptable.