Sismo vs Disco for Attestation Aggregation: ZK Badges vs Data Backpack

Core Advantage: Leverages Zero-Knowledge Proofs to create portable, privacy-preserving ZK Badges. Users prove group membership (e.g., 'ENS Holder') without revealing their specific identity or data source. This is critical for sybil-resistant airdrops and private reputation-based gating on platforms like Lens or Snapshot.

Core Advantage: Badges are stored as Soulbound Tokens (SBTs) on Ethereum L1/L2s (Polygon, Optimism). This creates a permanent, publicly verifiable, and composable reputation layer. Protocols like Aavegotchi and Galxe use this for on-chain credentialing, enabling trustless integrations.

Core Advantage: Focuses on a self-sovereign data model where users store Verifiable Credentials (VCs) in their personal Disco Data Backpack. This gives users granular control over data sharing via consent receipts, aligning with GDPR/CCPA compliance needs and enterprise data-sharing workflows.

Core Advantage: Supports a wide array of off-chain attestation schemas (W3C VCs, JSON-LD). This flexibility is ideal for integrating traditional credentials (KYC from Veriff, professional licenses) or complex data not suited for on-chain storage. It acts as a bridge between web2 identity and web3.

ZK-Proofs for Selective Disclosure: Users generate zero-knowledge proofs to claim badges without revealing underlying source data (e.g., a Gitcoin Passport score). This is critical for sybil-resistant airdrops and gated governance where user privacy is non-negotiable. Protocols like Lens and Aave leverage this for private reputation.

Soulbound NFTs as Universal Credentials: Badges are minted as non-transferable NFTs (ERC1155) on Ethereum L1/L2s, making them verifiable across any EVM dApp. This creates a composable, chain-agnostic reputation layer. Over 400,000 badges have been minted, demonstrating network effects.

Heavy Reliance on ZK Circuits: Implementing custom data groups (attestation logic) requires understanding ZK-SNARKs (Circom) and managing trusted setups. This creates a steeper learning curve compared to simpler signing schemes. Better for teams with cryptography expertise.

User-Centric Data Vault: Disco acts as a self-sovereign data backpack where users store verifiable credentials (VCs) following W3C standards. This is ideal for complex, multi-field attestations (e.g., professional licenses, educational records) that don't fit a simple badge model.

Ethereum Attestation Service (EAS) Integration: Disco uses EAS as a primary registry, offering a standardized, gas-efficient schema for attestations. This simplifies integration for issuers (like Coinbase or Guild.xyz) and verifiers, reducing development overhead.

Verifier Dependency on Centralized Infrastructure: While credentials are signed, the data payloads are typically stored off-chain (IPFS or centralized servers). Verifiers must resolve this data, introducing liveness and censorship risks not present with fully on-chain ZK badges.

Protocol-native aggregation: Sismo's ZK Badges are on-chain, non-transferable NFTs (ERC1155) that aggregate attestations from multiple sources (e.g., GitHub, Twitter, Ethereum) into a single, reusable proof. This enables permissionless integration with any dApp on supported chains (Ethereum, Polygon, Gnosis). Ideal for protocols needing sybil-resistant, composable reputation for airdrops or governance.

Selective disclosure by design: Users generate ZK proofs to claim badges without revealing the underlying source accounts (e.g., prove you have >100 GitHub followers without exposing your handle). This privacy-preserving model is critical for applications requiring verification without doxxing, such as private voting or confidential credential checks.

User-centric data sovereignty: Disco issues verifiable credentials (W3C standard) stored in a user-owned 'Data Backpack' (a decentralized identifier, or DID). Users present credentials directly to verifiers, maintaining control. This is superior for enterprise or real-world use cases (KYC, employment history) where data portability and issuer trust are paramount.

Schema-agnostic platform: Supports any credential type (JSON-LD, JWT) defined by issuers, enabling complex attestations for education, professional licenses, or DAO membership. Verification is off-chain by default, reducing gas costs. Best for custom, high-stakes attestation workflows that don't require on-chain composability for every action.

Gas-intensive minting: Each ZK Badge mint requires an on-chain transaction, creating friction and cost for users. App-specific integration is needed for dApps to read badge contracts. Less suitable for high-volume, low-value attestations where gas fees are prohibitive.

Off-chain verification hurdle: Credentials in the Data Backpack are not natively readable by smart contracts without a bridge (like Verax). This adds a layer of complexity for fully on-chain applications like DeFi or automated governance, which benefit from Sismo's directly queryable badges.