eip712-vc

Krebit EIP712 Verifiable Credentials SDK

This repository hosts the Krebit EIP712-VC tools, based on W3C Ethereum EIP712 Signature 2021 Draft.

It provides functions for creating both W3C compliant Verifiable Credentials, and also a Solidity compatible version that can be used in contracts like krebit-contracts.

Overview

Installation

$ npm install -s @krebitdao/eip721-vc

Configuring the EIP712 Domain

import {
  EIP712VC,
  VerifiableCredential,
  EIP712VerifiableCredential,
  DEFAULT_CONTEXT,
  EIP712_CONTEXT,
  DEFAULT_VC_TYPE,
  getEIP712Credential
} from '@krebitdao/eip721-vc';

let eip712vc = new EIP712VC({
  name: 'Krebit',
  version: '0.1',
  chainId: 4,
  verifyingContract: '0x00000000000000000000000000000000000000000000'
});

W3C EIP712 Verifiable Credentials

Creating

import { Wallet } from '@ethersproject/wallet';

let issuanceDate = Date.now();
let expirationDate = new Date();
expirationDate.setFullYear(expirationDate.getFullYear() + 3);

let issuerType = [{ name: 'id', type: 'string' }];

let credentialSubjectTypes = {
  CredentialSubject: [
    { name: 'type', type: 'string' },
    { name: 'id', type: 'string' },
    { name: 'name', type: 'string' },
    { name: 'child', type: 'Person' }
  ],
  Person: [
    { name: 'type', type: 'string' },
    { name: 'name', type: 'string' }
  ]
};

let credential = {
  '@context': [DEFAULT_CONTEXT, EIP712_CONTEXT],
  type: [DEFAULT_VC_TYPE],
  id: 'https://example.org/person/1234',
  issuer: {
    id: 'did:issuer'
  },
  credentialSubject: {
    type: 'Person',
    id: 'did:example:bbbbaaaa',
    name: 'Vitalik',
    child: {
      type: 'Person',
      name: 'Ethereum'
    }
  },
  credentialSchema: {
    id: 'https://example.com/schemas/v1',
    type: 'Eip712SchemaValidator2021'
  },
  issuanceDate: new Date(issuanceDate).toISOString(),
  expirationDate: new Date(expirationDate).toISOString(),
  proof: {
    verificationMethod: 'did:issuer#key-1',
    ethereumAddress: 'acc1',
    created: new Date(issuanceDate).toISOString(),
    proofPurpose: 'assertionMethod',
    type: 'EthereumEip712Signature2021'
  }
};

const wallet = Wallet.createRandom();

const vc: VerifiableCredential = await eip712vc.createW3CVerifiableCredential(
  credential,
  credentialSubjectTypes,
  async (data: TypedMessage<EIP712MessageTypes>) => {
    // Replace this fuction with your own signing code
    return signTypedData_v4(
      Buffer.from(wallet._signingKey().privateKey.slice(2), 'hex'),
      { data }
    );
  }
);

Creating Solidity Compatible EIP712 Verifiable Credentials

Creating

import { Wallet } from '@ethersproject/wallet';

let issuanceDate = Date.now();
let expirationDate = new Date();
expirationDate.setFullYear(expirationDate.getFullYear() + 3);

let issuerType = [
  { name: 'id', type: 'string' },
  { name: 'ethereumAddress', type: 'address' }
];

let credentialSubjectTypes = {
  CredentialSubject: [
    { name: 'id', type: 'string' },
    { name: 'ethereumAddress', type: 'address' },
    { name: '_type', type: 'string' },
    { name: 'typeSchema', type: 'string' },
    { name: 'value', type: 'string' },
    { name: 'encrypted', type: 'string' },
    { name: 'trust', type: 'uint8' },
    { name: 'stake', type: 'uint256' },
    { name: 'nbf', type: 'uint256' },
    { name: 'exp', type: 'uint256' }
  ]
};

let credential = {
  '@context': [DEFAULT_CONTEXT, EIP712_CONTEXT],
  type: [DEFAULT_VC_TYPE],
  id: 'https://example.org/person/1234',
  issuer: {
    id: 'did:issuer',
    ethereumAddress: 'acc1'
  },
  credentialSubject: {
    id: 'did:user',
    ethereumAddress: 'acc1',
    type: 'fullName',
    typeSchema: 'ceramic://def',
    value: 'encrypted',
    encrypted:
      '0x0c94bf56745f8d3d9d49b77b345c780a0c11ea997229f925f39a1946d51856fb',
    trust: 50,
    stake: 6,
    nbf: Math.floor(issuanceDate / 1000),
    exp: Math.floor(expirationDate.getTime() / 1000)
  },
  credentialSchema: {
    id: 'https://example.com/schemas/v1',
    type: 'Eip712SchemaValidator2021'
  },
  issuanceDate: new Date(issuanceDate).toISOString(),
  expirationDate: new Date(expirationDate).toISOString()
};

let eip712Credential = getEIP712Credential(credential);

const vc: EIP712VerifiableCredential = await eip712vc.createEIP712VerifiableCredential(
  eip712Credential,
  credentialSubjectTypes,
  async (data: TypedMessage<EIP712MessageTypes>) => {
    // Replace this fuction with your own signing code
    return signTypedData_v4(
      Buffer.from(wallet._signingKey().privateKey.slice(2), 'hex'),
      { data }
    );
  }
);

Creating Krebit Compatible EIP712 Verifiable Credentials

Creating

import { getKrebitCredentialTypes } from '@krebitdao/eip721-vc';

let issuanceDate = Date.now();
let expirationDate = new Date();
expirationDate.setFullYear(expirationDate.getFullYear() + 3);

let credential = {
  '@context': [DEFAULT_CONTEXT, EIP712_CONTEXT],
  type: [DEFAULT_VC_TYPE],
  id: 'https://example.org/person/1234',
  issuer: {
    id: 'did:issuer',
    ethereumAddress: 'acc1'
  },
  credentialSubject: {
    id: 'did:user',
    ethereumAddress: 'acc1',
    type: 'fullName',
    typeSchema: 'ceramic://def',
    value: 'encrypted',
    encrypted:
      '0x0c94bf56745f8d3d9d49b77b345c780a0c11ea997229f925f39a1946d51856fb',
    trust: 50,
    stake: 6,
    nbf: Math.floor(issuanceDate / 1000),
    exp: Math.floor(expirationDate.getTime() / 1000)
  },
  credentialSchema: {
    id: 'https://example.com/schemas/v1',
    type: 'Eip712SchemaValidator2021'
  },
  issuanceDate: new Date(issuanceDate).toISOString(),
  expirationDate: new Date(expirationDate).toISOString()
};

let eip712Credential = getEIP712Credential(credential);

let krebitTypes = getKrebitCredentialTypes();

const vc = await eip712vc.createEIP712VerifiableCredential(
  eip712Credential,
  krebitTypes,
  async data => {
    // Replace this fuction with your own signing code
    return await issuerSigner._signTypedData(
      {
        name: 'Krebit',
        version: '0.1',
        chainId: 4,
        verifyingContract: '0x00000000000000000000000000000000000000000000'
      },
      krebitTypes,
      credential
    );
  }
);

Verifying

eip712vc.verifyEIP712Credential(
  issuerAddress,
  eip712Credential,
  krebitTypes,
  vc.proof.proofValue,
  async (data: TypedMessage<EIP712MessageTypes>, proofValue: string) => {
    // Replace this fuction with your own signing code
    return recoverTypedSignature_v4({ data, sig: proofValue });
  }
);

Learn More

The guides in the docs site will teach about different concepts of the Krebit Protocol.

Contribute

Krebit Protocol exists thanks to its contributors. There are many ways you can participate and help build public goods. Check out the Krebit Gitcoin Grants!

License

Krebit EIP712-VC is released under the ISC License.