On-Chain Registry vs Off-Chain Status List

Decentralized Trust: Status is anchored directly on a public ledger (e.g., Ethereum, Polygon). Verification is a simple, permissionless read call. This matters for high-stakes credentials (e.g., KYC attestations, legal documents) where auditability is non-negotiable.

Higher Base Cost: Writing and updating status incurs gas fees. On Ethereum Mainnet, a simple registry update can cost $5-$50+. This matters for high-volume, low-value credentials (e.g., event tickets, gaming achievements) where cost can become prohibitive.

Near-Zero Operational Cost: Status is managed in a signed JSON file (W3C Status List 2021) hosted off-chain (e.g., AWS S3, IPFS). Updating a list of 10,000 revocations costs pennies. This matters for mass-market applications (e.g., employee badges, university diplomas) requiring frequent updates.

Verifier Trust Assumption: Verifiers must trust the issuer to maintain the list's availability and integrity. While signatures can be cached, a DDoS attack on the endpoint can break verification. This matters for long-lived credentials (e.g., professional licenses) where the issuer's infrastructure must be reliable for decades.

Unconditional Verifiability: Status checks are resolved via a single, immutable on-chain lookup (e.g., an Ethereum smart contract). This provides cryptographic finality and eliminates reliance on any external service provider. This matters for high-value credentials like KYC attestations or asset-backed tokens where the status source must be beyond dispute.

High Operational Cost & Latency: Every status update (revocation, issuance) requires a blockchain transaction. On Ethereum, this can cost $5-$50+ in gas and be subject to 12-second block times. This matters for large-scale, dynamic credential systems (e.g., event tickets, subscription badges) where frequent, low-cost updates are critical.

High Scalability & Low Cost: Status is managed in a signed, off-chain JSON document (W3C Status List 2021). Issuers can revoke thousands of credentials with a single signature update, costing pennies in cloud storage. This matters for mass-market applications like university diplomas or employee badges where issuance volume is high and cost-per-credential must be near zero.

Issuer Availability Dependency: Verifiers must fetch the latest status list from the issuer's endpoint (HTTP/S3, IPFS). This introduces a trust assumption in the issuer's operational uptime and introduces a potential central point of failure. This matters for long-lived credentials where the issuer may not exist in 10 years, or for scenarios requiring verifier-side caching complexity.

Guaranteed State Consistency: Every credential status update is a verifiable on-chain transaction (e.g., Ethereum, Solana). This provides cryptographic finality and eliminates reliance on external availability services. This matters for high-value, low-frequency credentials like corporate KYC attestations or property titles.

Cost and Latency Overhead: Each status update (revocation, suspension) incurs a network transaction fee. On Ethereum, this can be $5-$50+ per update, making it prohibitive for high-volume, ephemeral credentials. Latency is bound by block times (12 sec on Ethereum, ~400ms on Solana). This matters for use cases like event tickets or hourly access tokens.

High Throughput & Low Cost: Status for millions of credentials can be updated in a single, signed data structure (like a JSON file or Merkle tree). Zero on-chain fees for status changes, enabling scalable use cases like university diplomas (10k+ graduates/year) or employee badges. Protocols like W3C VC Status List 2021 standardize this.

Availability and Freshness Risk: Verifiers must fetch the latest status list from a publisher's server or decentralized storage (IPFS, Arweave). This introduces liveness dependencies and potential for stale data if caches aren't updated. This matters for real-time fraud prevention in DeFi lending or high-security access control systems.