Sismo's ZK Badges excel at privacy-preserving reputation aggregation because they use zero-knowledge proofs to generate new attestations without revealing the underlying source data. For example, a user can prove they hold a specific NFT or are part of a DAO without exposing their wallet address, minting a new, private badge like a Proof of Humanity ZK Badge. This architecture is ideal for applications like private governance or gated experiences where user anonymity is paramount.
LABS
Comparisons
Sismo's ZK Badges vs Gitcoin Passport Stamps
A technical analysis comparing two leading on-chain identity primitives: Sismo's privacy-preserving, reusable ZK Badges for access control versus Gitcoin Passport's aggregated score for sybil resistance and funding defense.
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introduction
THE ANALYSIS
Introduction: The Two Philosophies of On-Chain Identity
Sismo's ZK Badges and Gitcoin Passport represent two distinct architectural approaches to decentralized identity, forcing a fundamental choice between privacy and composability.
Gitcoin Passport takes a different approach by aggregating verifiable credentials into a public, portable score. This strategy results in a transparent and composable identity layer where a user's Passport score (e.g., 20+ points from sources like BrightID, ENS, and Coinbase) is openly verifiable by any application. This public composability has driven significant adoption, with over 500,000 Passports created, making it the de facto standard for Sybil-resistant airdrops and grant distributions in ecosystems like Optimism and Arbitrum.
The key trade-off: If your priority is user privacy and creating new, non-transferable reputation signals, choose Sismo. If you prioritize public Sybil resistance, maximal composability across DeFi and governance apps, and leveraging an existing user base, choose Gitcoin Passport.
tldr-summary
Sismo ZK Badges vs. Gitcoin Passport Stamps
TL;DR: Core Differentiators at a Glance
A high-level comparison of two leading decentralized identity solutions, highlighting their architectural trade-offs and ideal applications.
03
Sismo's Key Strength: ZK Privacy
Specific advantage: Provenance of a badge is cryptographically verified without revealing the underlying attestation (e.g., a specific GitHub contribution or Ethereum transaction). This enables private proof-of-humanity and selective disclosure for complex DAO roles.
04
Gitcoin's Key Strength: Composability & Adoption
Specific advantage: 2M+ Passports created and integrated across 300+ apps. Its Scorer API and Stamp ecosystem make it a plug-and-play solution for developers needing immediate, broad-based sybil scoring without building ZK circuits.
05
Sismo Trade-off: Developer Complexity
Specific consideration: Requires understanding of ZK circuits (Circom) and data attestation schemas. While the ZK Badge infrastructure is robust, initial integration is more involved than using a simple scoring API.
06
Gitcoin Passport Trade-off: Centralized Aggregator
Specific consideration: The Passport score is computed by Gitcoin's centralized scorer. While the VCs are in your wallet, the scoring algorithm and weightings are opaque and controlled by a single entity, introducing a trust assumption.
SISMO ZK BADGES VS GITCOIN PASSPORT STAMPS
Head-to-Head Feature Comparison
Direct comparison of key metrics and features for on-chain identity and reputation systems.
| Metric | Sismo ZK Badges | Gitcoin Passport Stamps |
|---|---|---|
Privacy Model | Zero-Knowledge Proofs (ZK) | Aggregated Public Attestations |
On-Chain Verification Cost | $0.50 - $2.00 | $0.10 - $0.50 |
Primary Use Case | Private Reputation & Access Gating | Sybil-Resistant Governance |
Data Storage | On-Chain (Badge NFT) | Off-Chain (Ceramic Network) |
Interoperability Standard | ERC-1155, ERC-721 | EAS (Ethereum Attestation Service) |
Native Sybil Resistance | ||
Direct Data Portability |
pros-cons-a
PROS AND CONS
Sismo ZK Badges vs Gitcoin Passport Stamps
A data-driven comparison of two leading on-chain identity solutions for CTOs and Protocol Architects. Key strengths and trade-offs at a glance.
02
Sismo ZK Badges: Modular & Composable
Badges are non-transferable, soulbound NFTs (ERC1155) minted on a user's Sismo Vault, not their main wallet. This enables credential aggregation (e.g., combining a Gitcoin Passport score with a Lens Protocol follow) into a single, reusable proof. This matters for creating complex, cross-protocol reputation systems.
ERC1155
Token Standard
03
Sismo ZK Badges: Higher Implementation Complexity
Requires integrating the Sismo Protocol and Data Vault, adding architectural overhead versus a simple API call. Developers must manage ZK circuits and attestation logic. This matters for teams with limited crypto-native engineering resources or projects needing a simple, fast integration.
05
Gitcoin Passport: Cost-Effective Verification
No gas fees for users to create or update their Passport. Stamps are stored off-chain with cryptographic proofs; only the score is used on-chain via a verifier contract. This matters for mass adoption scenarios where user onboarding cost and friction are critical barriers.
06
Gitcoin Passport: Less Granular Privacy
Stamp data is publicly viewable on the Passport app, revealing which specific verifiers a user has connected. The aggregated score is the primary privacy-preserving output. This matters for applications where the composition of a user's identity must remain confidential beyond a simple score.
pros-cons-b
Sismo ZK Badges vs Gitcoin Passport Stamps
Gitcoin Passport Stamps: Pros and Cons
Key strengths and trade-offs for decentralized identity verification at a glance.
01
Sismo ZK Badge: Privacy & Composability
Zero-Knowledge Proofs: Users generate badges from source data (e.g., ENS, PoH) without revealing the underlying credentials. This is critical for privacy-preserving applications like private voting or gated communities. On-Chain & Portable: Badges are minted as Soulbound Tokens (SBTs) on Ethereum L2s (Polygon zkEVM, Gnosis Chain), making them composable across DeFi and governance dApps like Aave Governance.
02
Sismo ZK Badge: Granular Attestations
Flexible Data Sources: Badges can attest to specific, provable claims (e.g., "Top 100 Snapshot voter," "Gitcoin Grants donor") rather than a generic score. This enables fine-grained access control for protocols like Lens Protocol or zkSync ecosystem apps. Developer SDK: Offers a ZK Connect protocol for easy integration, allowing dApps to request specific badges with customizable ZK circuits.
03
Gitcoin Passport: Sybil Resistance & Adoption
Aggregated Trust Score: Combines 20+ verifiable stamps (BrightID, ENS, Proof of Humanity) into a single, updatable score. This is the established standard for Sybil resistance in quadratic funding rounds, protecting over $50M+ in Gitcoin Grants. Wide Integration: Directly integrated into major platforms like Optimism's RetroPGF, Arbitrum's DAO governance, and Coinbase's Verifications.
04
Gitcoin Passport: Ease of Use & Maintenance
Non-Technical User Focus: Simple web app for users to collect stamps; no need to understand ZK proofs or manage wallets for each credential. Centralized Indexer (Trade-off): Passport scores are computed off-chain by Gitcoin's indexer, simplifying reads for dApps but introducing a dependency on Gitcoin's infrastructure versus Sismo's fully on-chain model.
05
Choose Sismo ZK Badges If...
Your protocol requires:
- Maximum user privacy (ZK proofs).
- On-chain, composable attestations for DeFi or governance logic.
- Granular, custom credentials beyond a generic score.
Ideal for: Private DAO voting, exclusive NFT gating, proving specific on-chain achievements.
06
Choose Gitcoin Passport If...
Your application needs:
- Battle-tested Sybil resistance for funding or reward distribution.
- Broad user adoption with a simple UX.
- Integration with major grant & governance platforms (Optimism, Arbitrum).
Ideal for: Quadratic funding, airdrop eligibility filters, general-purpose uniqueness scoring.
CHOOSE YOUR PRIORITY
When to Choose Which: A Use Case Breakdown
Sismo ZK Badges for Protocol Architects
Verdict: The superior choice for building privacy-preserving, composable identity layers. Strengths: Sismo's core value is ZK-proof portability. Badges are non-transferable, privacy-preserving attestations that can be aggregated into a single ZK proof (the Sismo Vault). This enables complex, sybil-resistant gating logic without exposing user data or linking identities across applications. For architects designing a decentralized social graph or a reputation-based governance system, Sismo's modular, on-chain attestations are a powerful primitive. Integration is via their Sismo Connect protocol, allowing for flexible verification of badge ownership or specific claim combinations.
Gitcoin Passport for Protocol Architects
Verdict: The pragmatic, off-chain-first solution for rapid integration of web2 and web3 signals. Strengths: Gitcoin Passport excels at aggregating disparate identity signals (e.g., BrightID, ENS, Twitter, Google) into a single, updatable Stamps collection and a scoring algorithm. Its primary output is a Passport Score, ideal for simple, weighted sybil-resistance checks. For architects needing a quick, maintained solution for a retroactive funding round or a community airdrop with basic sybil filters, Passport's API is straightforward. However, its reliance on centralized scoring and off-chain Stamp storage means less cryptographic guarantee and composability compared to Sismo.
verdict
THE ANALYSIS
Final Verdict and Decision Framework
Choosing between ZK Badges and Passport Stamps hinges on your protocol's need for privacy and verifiable computation versus broad attestation and composability.
Sismo's ZK Badges excel at privacy-preserving, granular reputation because they are built on zero-knowledge proofs. For example, a user can prove they own a specific NFT or have a certain on-chain transaction volume without revealing their wallet address, enabling applications like private governance or gated access. This cryptographic approach, leveraging tools like the Sismo Data Vault and the Sismo Hub, is ideal for use cases requiring selective disclosure and Sybil resistance without doxxing.
Gitcoin Passport Stamps take a different approach by aggregating verifiable credentials from a wide array of sources—both on-chain (like ENS, POAP) and off-chain (like BrightID, Idena). This results in a more accessible, composable, and web2-friendly score but relies on the security and availability of centralized validators for many stamp providers. The system's strength is its network effect, with over 500,000 Passports created, making it a de facto standard for Sybil-resistant quadratic funding and broad identity aggregation.
The key trade-off: If your priority is cryptographic privacy, data minimization, and building novel reputation primitives, choose Sismo ZK Badges. If you prioritize maximizing user accessibility, leveraging a widely adopted scoring system, and integrating with the existing Gitcoin Grants ecosystem, choose Gitcoin Passport Stamps. For CTOs, the decision maps to architectural philosophy: ZK Badges for a trust-minimized, self-sovereign future; Passport for practical, large-scale adoption today.
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