Attestations

Overview

Attestations are cryptographically signed claims about identities, behaviors, or achievements that enable trust verification across the ZKScore ecosystem.

Attestation Structure

Basic Attestation

const attestation = {
  attester: '0x...', // Address of the attester
  recipient: '0x...', // Address of the recipient
  schema: '0x...', // Schema UID
  data: '0x...', // Encoded attestation data
  expiration: 0, // Expiration timestamp (0 = no expiration)
  revocable: true, // Whether attestation can be revoked
  signature: '0x...' // Cryptographic signature
};

Schema Definition

const schema = {
  name: 'Skill Verification',
  description: 'Verifies a user has specific skills',
  fields: [
    { name: 'skill', type: 'string' },
    { name: 'level', type: 'uint256' },
    { name: 'verifiedBy', type: 'address' }
  ]
};

Creating Attestations

1. Define Attestation Data

// Attestation data
const attestationData = {
  skill: 'Solidity Development',
  level: 5,
  verifiedBy: '0x1234567890123456789012345678901234567890'
};

// Encode data according to schema
const encodedData = ethers.utils.defaultAbiCoder.encode(
  ['string', 'uint256', 'address'],
  [attestationData.skill, attestationData.level, attestationData.verifiedBy]
);

2. Create Attestation

// Create attestation
const tx = await trustRegistry.createAttestation(
  recipientAddress, // recipient
  schemaUID, // schema
  encodedData, // encoded data
  expirationTime, // expiration (0 = no expiration)
  true // revocable
);

await tx.wait();
console.log('Attestation created!', tx.hash);

// Create attestation in contract
trustRegistry.createAttestation(
  recipient,
  schemaUID,
  encodedData,
  expirationTime,
  true
);

3. Verify Attestation

// Get attestation
const attestationUID = await trustRegistry.getLatestAttestationUID();
const attestation = await trustRegistry.getAttestation(attestationUID);

console.log('Attestation:', attestation);

// Verify attestation validity
const isValid = await trustRegistry.isValidAttestation(attestationUID);
console.log('Is valid:', isValid);

Attestation Types

Skill Verification

const skillAttestation = {
  schema: 'skill-verification',
  data: {
    skill: 'Smart Contract Development',
    level: 8,
    verifiedBy: '0x...',
    timestamp: Date.now()
  }
};

Identity Verification

const identityAttestation = {
  schema: 'identity-verification',
  data: {
    verificationType: 'KYC',
    level: 'enhanced',
    issuer: '0x...',
    expiration: Date.now() + (365 * 24 * 60 * 60 * 1000) // 1 year
  }
};

Achievement Verification

const achievementAttestation = {
  schema: 'achievement-verification',
  data: {
    achievement: 'DeFi Pioneer',
    protocol: 'uniswap',
    verifiedBy: '0x...',
    timestamp: Date.now()
  }
};

Attestation Verification

On-chain Verification

// Verify attestation exists and is valid
async function verifyAttestation(attestationUID) {
  const attestation = await trustRegistry.getAttestation(attestationUID);
  
  if (!attestation) {
    return { valid: false, reason: 'Attestation not found' };
  }
  
  if (attestation.revoked) {
    return { valid: false, reason: 'Attestation revoked' };
  }
  
  if (attestation.expiration > 0 && Date.now() > attestation.expiration) {
    return { valid: false, reason: 'Attestation expired' };
  }
  
  return { valid: true, attestation };
}

Batch Verification

// Verify multiple attestations
async function verifyAttestations(attestationUIDs) {
  const results = await Promise.all(
    attestationUIDs.map(uid => verifyAttestation(uid))
  );
  
  return results.filter(result => result.valid);
}

Revoking Attestations

Revoke Attestation

// Revoke attestation
const tx = await trustRegistry.revokeAttestation(attestationUID);
await tx.wait();
console.log('Attestation revoked!', tx.hash);

// Revoke in contract
trustRegistry.revokeAttestation(attestationUID);

Check Revocation Status

// Check if attestation is revoked
const isRevoked = await trustRegistry.isAttestationRevoked(attestationUID);
console.log('Is revoked:', isRevoked);

Trust Modules

Custom Trust Logic

// Custom trust module
const trustModule = {
  name: 'Skill Trust Module',
  description: 'Evaluates trust based on skill attestations',
  logic: `
    function evaluateTrust(address user) public view returns (uint256) {
      // Custom trust evaluation logic
      uint256 skillScore = getSkillScore(user);
      uint256 verificationScore = getVerificationScore(user);
      return (skillScore + verificationScore) / 2;
    }
  `
};

Register Trust Module

// Register trust module
const tx = await trustRegistry.registerTrustModule(
  trustModule.name,
  trustModule.description,
  trustModuleContractAddress
);

await tx.wait();
console.log('Trust module registered!', tx.hash);

Best Practices

Clear Schemas: Define clear, well-documented schemas
Appropriate Expiration: Set reasonable expiration times
Secure Signing: Use secure key management for signing
Regular Verification: Periodically verify attestation validity
Privacy Considerations: Consider data privacy in attestations

Smart Contracts

IdentitySBT

ScoreCalculator

AchievementRegistry

TrustRegistry

ProtocolRegistry

Contract Examples

Overview

Attestation Structure

Basic Attestation

Schema Definition

Creating Attestations

1. Define Attestation Data

2. Create Attestation

3. Verify Attestation

Attestation Types

Skill Verification

Identity Verification

Achievement Verification

Attestation Verification

On-chain Verification

Batch Verification

Revoking Attestations

Revoke Attestation

Check Revocation Status

Trust Modules

Custom Trust Logic

Register Trust Module

Best Practices

​Overview

​Attestation Structure

​Basic Attestation

​Schema Definition

​Creating Attestations

​1. Define Attestation Data

​2. Create Attestation

​3. Verify Attestation

​Attestation Types

​Skill Verification

​Identity Verification

​Achievement Verification

​Attestation Verification

​On-chain Verification

​Batch Verification

​Revoking Attestations

​Revoke Attestation

​Check Revocation Status

​Trust Modules

​Custom Trust Logic

​Register Trust Module

​Best Practices

​Related Documentation

Overview

Attestation Structure

Basic Attestation

Schema Definition

Creating Attestations

1. Define Attestation Data

2. Create Attestation

3. Verify Attestation

Attestation Types

Skill Verification

Identity Verification

Achievement Verification

Attestation Verification

On-chain Verification

Batch Verification

Revoking Attestations

Revoke Attestation

Check Revocation Status

Trust Modules

Custom Trust Logic

Register Trust Module

Best Practices

Related Documentation