@krebitdao/eip712-vc NPM

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.

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