Service Credential

A Service Credential is a verifiable attestation issued by a service provider and recorded on-chain, typically as an ERC-1155 token or a Soulbound Token (SBT). This provides cryptographic proof that a user or contract holds a specific permission or has passed a certain check, such as KYC verification or a credit score threshold. The on-chain nature ensures the credential is tamper-proof and its issuance history is transparent.

Unlike traditional, siloed API keys, Service Credentials are portable assets that users control. A credential issued by one protocol (e.g., a proof of identity) can be composed and reused across multiple, unrelated applications (DeFi, gaming, social) without re-verification. This creates a permission graph where dApps can trustlessly query a user's aggregated credentials to grant access or tailor services.

Credentials can embed programmable logic for automated lifecycle management. Key features include:

• Time-based expiry: Credentials can be valid for a fixed period (e.g., 30-day subscription).
• Conditional revocation: The issuer or a predefined smart contract can revoke the credential based on on-chain events (e.g., loan default).
• Renewal mechanisms: Enable seamless, permissioned renewal flows without full re-issuance.

Using zero-knowledge proofs (ZKPs) or similar cryptographic techniques, users can prove they hold a valid credential without revealing the underlying data. For example, a user can prove they are over 18 or have a sufficient credit score without disclosing their birthdate or exact score. This enables selective disclosure, balancing compliance needs with user privacy.

Interoperability is driven by standardized data schemas. Initiatives like ERC-7230 (Data Container) define a common format for credential metadata, claim structure, and issuer identification. This allows any dApp to parse and validate credentials from any compliant issuer, creating a universal language for on-chain reputation and access rights.

A prime example is credit-based DeFi lending. A user obtains a Service Credential from a rater attesting to a credit score > 700. The user then presents this credential to a lending protocol. The protocol's smart contract verifies the credential's validity and issuer, then grants a loan with a lower collateral requirement than the anonymous, over-collateralized standard. The credential acts as programmable, verifiable collateral.

Service Credentials function as programmable access tokens that dApps use to gate features. This enables use cases like:

• Token-gated communities requiring a specific NFT or token balance.
• Reputation-based lending where a credential proves a wallet's on-chain history qualifies it for better rates.
• Exclusive airdrops distributed only to wallets with a credential proving past protocol interaction.

By tying service access to a verifiable, non-transferable credential, protocols can defend against Sybil attacks where a single entity creates many fake accounts. This is critical for:

• Fair launch distributions and airdrops.
• One-person-one-vote governance systems.
• Preventing farming bots from exploiting liquidity incentives. The credential acts as a proof of unique personhood or legitimate past activity.

Credentials are composable data objects that can be built upon by multiple protocols. A wallet's reputation becomes a portable asset:

• A credential from a lending protocol proving timely repayment can be used to access a new protocol with reduced collateral requirements.
• A DAO contribution credential can grant voting power in a related ecosystem project.
• This creates a user-owned on-chain resume that transcends any single application.

Smart contracts can programmatically check for credentials to trigger actions, enabling trustless automation. Examples include:

• Auto-whitelisting for a mint if a user holds a credential from a partner project.
• Streaming payments that start only after a credential proving task completion is issued.
• Dynamic NFT evolution where the NFT's traits change based on credentials earned through specific interactions.

Service Credentials are typically built on attestation standards like EAS (Ethereum Attestation Service) or Verifiable Credentials (VCs). Key properties:

• Verifiable: Anyone can cryptographically verify the issuer and integrity.
• Revocable: The issuer can invalidate the credential if needed.
• Context-Rich: Can contain specific claims (e.g., score > 100, memberSince > 2023).
• This foundation ensures credentials are trust-minimized and interoperable across the ecosystem.

An Attestation is a broader term for any statement or assertion made by one entity about another. In the context of Service Credentials:

• A Service Credential is a specific, standardized form of a blockchain attestation.
• It moves beyond simple on-chain data to a portable, reusable, and verifiable claim.
• Other forms of attestations include on-chain registry entries or simple signed messages, which lack the formal structure of a VC.

A Zero-Knowledge Proof is a cryptographic method allowing one party to prove knowledge of a secret or the truth of a statement without revealing the underlying data. It enhances Service Credentials by enabling:

• Selective Disclosure: Proving you hold a credential meeting certain criteria (e.g., "KYC-compliant") without revealing your full identity.
• Privacy-Preserving Verification: Allowing service providers to verify eligibility without accessing sensitive holder data.
• Minimal on-chain footprints by verifying proofs instead of storing raw credentials.

A Trust Registry is a decentralized, on-chain list that defines which entities are authorized to issue specific types of Service Credentials. It acts as a governance layer by:

• Listing approved DIDs or smart contract addresses for issuers.
• Defining the schema types (e.g., KYCProvider) they are permitted to issue.
• Enabling verifiers to check an issuer's authority before trusting a presented credential, moving trust from individual issuers to the registry's governance.

A Schema defines the precise data structure for a type of Service Credential. It is a critical component for interoperability, specifying:

• The required and optional attributes (e.g., developerScore, expiryDate).
• The data types for each attribute (string, integer, timestamp).
• Often stored on-chain or in decentralized storage (like IPFS), schemas allow issuers, holders, and verifiers to agree on the credential's format, ensuring machines can process them uniformly.