Attestation Protocols

For a simpler integration, use the Individual Verifications API which provides convenient endpoints that handle attestation queries for you.

Individual Verifications issue attestations through Sign Protocol , allowing you to query and validate verification status directly on-chain. This page covers the attestation schemas, how to query them, and how to validate the data.

Sign Protocol Overview

Every Individual Verification (Government ID, Phone, Biometrics, Clean Hands) issues a Sign Protocol attestation when a user completes verification. These attestations are stored on-chain and can be queried by any application.

Key Addresses

Component	Address
Attester (Relayer)	`0xB1f50c6C34C72346b1229e5C80587D0D659556Fd`

Schema IDs by Network

Environment	Schema ID	Network	Chain ID
Production	`onchain_evm_10_0x1`	Optimism	10
Production	`onchain_evm_10_0x8`	Base	8453
Sandbox	`onchain_evm_11155420_0xc41`	Optimism Sepolia	11155420

API Endpoints

Environment	Endpoint
Production	`https://mainnet-rpc.sign.global/api/index/attestations`
Sandbox	`https://testnet-rpc.sign.global/api/index/attestations`

Attestation Schema

Individual Verification attestations contain a ZK proof that encodes the verification type, action ID, and issuer information.

Raw Schema


string circuitId, uint256[] publicValues

Fields

Field	Type	Description
`circuitId`	string	Identifies the verification type (see Circuit IDs below)
`publicValues`	uint256[]	Array of public values from the ZK proof

Public Values Array

The publicValues array contains the following elements:

Index	Field	Description
0	`nullifierHash`	Unique identifier preventing duplicate verifications
1	`signedCredentialHash`	Hash of the signed credential
2	`actionId`	The action ID used for sybil resistance
3	`expiresAt`	Unix timestamp when the verification expires
4	`issuer`	Address of the credential issuer
5	`recipient`	Address that received the attestation

Circuit IDs

Each verification type has a unique circuit ID that identifies what kind of verification the attestation represents.

Verification Type	Circuit ID
Government ID (KYC)	`0x729d660e1c02e4e419745e617d643f897a538673ccf1051e093bbfa58b0a120b`
Phone	`0xbce052cf723dca06a21bd3cf838bc518931730fb3db7859fc9cc86f0d5483495`
Biometrics	`0x0b5121226395e3b6c76eb8ddfb0bf2f2075e7f2c6956567e84b38a223c3a3d15`

Issuer Addresses

Each verification type has an associated issuer address that must be validated.

Production Issuers

Verification Type	Issuer Address
Government ID (KYC)	`0x03fae82f38bf01d9799d57fdda64fad4ac44e4c2c2f16c5bf8e1873d0a3e1993`
Phone	`0x40b8810cbaed9647b54d18cc98b720e1e8876be5d8e7089d3c079fc61c30a4`
Biometrics	`0x0d4f849df782fb9e68d525fbda10b73e59180e59cb2a21ce5d70ccc45dbfd922`

Sandbox Issuers

Verification Type	Issuer Address
Government ID (KYC)	`0x2332221496ffef62c0075ce833b54c5c0b78419be2571e8d1715f7990fc5279a`
Phone	`0x1c0288e0fbbab4e1dda4732a72b391e9616d88c5d1fcfb97124584f2506645c3`

Querying Attestations

Query by Schema and Attester

Use the Sign Protocol API to query all attestations for a specific schema.


curl 'https://mainnet-rpc.sign.global/api/index/attestations?schemaId=onchain_evm_10_0x1&attester=0xB1f50c6C34C72346b1229e5C80587D0D659556Fd'

Query by Recipient Address

To find attestations for a specific user:


curl 'https://mainnet-rpc.sign.global/api/scan/addresses/{address}/attestations'

Response Format


{
  "data": {
    "page": 1,
    "rows": [
      {
        "attestTimestamp": "1714819085000",
        "attestationId": "0x65",
        "attester": "0xB1f50c6C34C72346b1229e5C80587D0D659556Fd",
        "chainId": "10",
        "data": "0x000000...",
        "recipients": ["0xEdedf460A77928f59c27f37F73D4853FD8a07984"],
        "revoked": false,
        "schema": {
          "name": "HolonymV3",
          "description": "Holonym V3"
        },
        "validUntil": 1770922106
      }
    ],
    "size": 100,
    "total": 195
  }
}

Validating Attestations

When validating an attestation, verify the circuit ID, action ID, issuer, and expiration.

TypeScript Example


import { ethers } from "ethers";
 
// Expected values for Government ID verification
const EXPECTED_CIRCUIT_ID = "0x729d660e1c02e4e419745e617d643f897a538673ccf1051e093bbfa58b0a120b";
const EXPECTED_ISSUER = "0x03fae82f38bf01d9799d57fdda64fad4ac44e4c2c2f16c5bf8e1873d0a3e1993";
const EXPECTED_ACTION_ID = "123456789";
const ATTESTER = "0xB1f50c6C34C72346b1229e5C80587D0D659556Fd";
 
interface AttestationValidation {
  isValid: boolean;
  error?: string;
}
 
function validateGovIdAttestation(attestation: any): AttestationValidation {
  // Check attester
  if (attestation.attester.toLowerCase() !== ATTESTER.toLowerCase()) {
    return { isValid: false, error: "Invalid attester" };
  }
 
  // Check not revoked
  if (attestation.revoked) {
    return { isValid: false, error: "Attestation revoked" };
  }
 
  // Check expiration
  const now = Math.floor(Date.now() / 1000);
  if (attestation.validUntil && attestation.validUntil < now) {
    return { isValid: false, error: "Attestation expired" };
  }
 
  // Decode and validate attestation data
  const decoded = ethers.utils.defaultAbiCoder.decode(
    ["string", "uint256[]"],
    attestation.data
  );
 
  const circuitId = decoded[0];
  const publicValues = decoded[1];
  const actionId = publicValues[2];
  const issuer = publicValues[4];
 
  // Validate circuit ID
  if (circuitId !== EXPECTED_CIRCUIT_ID) {
    return { isValid: false, error: "Invalid circuit ID" };
  }
 
  // Validate action ID
  if (actionId.toString() !== EXPECTED_ACTION_ID) {
    return { isValid: false, error: "Invalid action ID" };
  }
 
  // Validate issuer
  if (issuer.toHexString() !== EXPECTED_ISSUER) {
    return { isValid: false, error: "Invalid issuer" };
  }
 
  return { isValid: true };
}

Proof of Clean Hands Attestations

Proof of Clean Hands uses a different schema on Base (chain ID 8453).

Query Clean Hands Attestations


curl 'https://mainnet-rpc.sign.global/api/scan/addresses/{address}/attestations'

Validation


function hasValidCleanHandsAttestation(attestations: any[]): boolean {
  const now = Math.floor(Date.now() / 1000);
  const CLEAN_HANDS_SCHEMA = 'onchain_evm_10_0x8';
  const ATTESTER = '0xB1f50c6C34C72346b1229e5C80587D0D659556Fd';
 
  return attestations.some(att =>
    att.fullSchemaId === CLEAN_HANDS_SCHEMA &&
    att.attester.toLowerCase() === ATTESTER.toLowerCase() &&
    att.isReceiver === true &&
    att.revoked === false &&
    att.validUntil > now
  );
}

Sign Protocol Explorer

You can view attestations on the Sign Protocol explorer:

Production: https://scan.sign.global
View specific attestation: https://scan.sign.global/attestation/{attestationId}

Action IDs

Action IDs enable sybil resistance by enforcing “1 person = 1 action”. The default action ID is 123456789.

For more information on action IDs and custom action IDs, see Action IDs.

Additional Resources

Sign Protocol Documentation
Individual Verifications API - Simpler API for verification checks
Testing - Test your integration on Base Sepolia