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Using Core Kit SFA Node SDK

Once you've installed and successfully initialized Web3Auth, you can use it to authenticate your users. Further, you can use the native provider given by Web3Auth to connect the users to the respective blockchain network.

Natively, the instance of Web3Auth (referred to as web3auth in our examples) returns the following functions:

  • connect() - Logs in the User using the verifier, verifierId & idToken.

Logging in your User​

connect()

To login a user in the Web3Auth SFA Node.js SDK, you need to call connect() function.

VariableDescription
loginParamsMandatory login parameters

Returns​

connect(loginParams: LoginParams): Promise<SafeEventEmitterProvider | null>
Note

One needs to re-initialize the SDK for each new user.

On successful login, the connect() function returns a SafeEventEmitterProvider instance. This instance contains the respective provider corresponding to your selected blockchain. You can use this provider to connect your user to the blockchain and make transactions.

On unsuccessful login, this function will return a null value.

connect(loginParams: LoginParams)​

LoginParams

ParameterDescription
verifierDetails of the verifier (verifier type, ie. torus, metamask, openlogin etc.). It's a mandatory parameter as a string.
verifierIdVerifier ID's value, sub or email value present in the idToken and not the string sub or email. It's a mandatory parameter as a string.
idTokenA newly created JWT Token that has not already been sent to Web3Auth or a Duplicate Token error will be thrown. It's a mandatory parameter as a string.
subVerifierInfoArray?Sub verifier info. It's an optional parameter as a TorusSubVerifierInfo[].
Usage
await web3auth.connect({
  verifier: "verifier-name", // e.g. `web3auth-sfa-verifier` replace with your verifier name, and it has to be on the same network passed in init().
  verifierId: "verifier-id-value", // e.g. `Yux1873xnibdui` or `name@email.com` replace with your verifier id(sub or email)'s value.
  idToken: "JWT Token", // replace with your newly created unused JWT Token.
});
Note

@web3auth/single-factor-auth SDK only works for users who have not enabled MFA.

MFA enabled users

For MFA enabled users, you'll see Error("User has already enabled mfa, please use the @webauth/webauth-web sdk for login with mfa");

Example​

Custom JWT Example​

Custom JWT Example
const { Web3Auth } = require("@web3auth/node-sdk");
const { EthereumPrivateKeyProvider } = require("@web3auth/ethereum-provider");
const jwt = require("jsonwebtoken");
const fs = require("fs");

// Use "openssl genrsa -out privateKey.pem 2048" to generate a private key
// Also, use this private key to generate a public key using "openssl rsa -in privateKey.pem -pubout -out publicKey.pem"
// Convert PEM to JWKS and expose it on a public URL, and make a web3auth verifier using that.
// Check out https://web3auth.io/docs/auth-provider-setup/byo-jwt-provider/ for more details.
var privateKey = fs.readFileSync("privateKey.pem");

const privateKeyProvider = new EthereumPrivateKeyProvider({
  config: {
    chainConfig: {
      chainId: "0xaa36a7",
      rpcTarget: "https://rpc.ankr.com/eth_sepolia",
      displayName: "Ethereum Sepolia",
      blockExplorerUrl: "https://sepolia.etherscan.io/",
      ticker: "ETH",
      tickerName: "Ethereum",
    },
  },
});

// Instantiate Web3Auth Node.js SDK
const web3auth = new Web3Auth({
  clientId: "WEB3AUTH_CLIENT_ID", // Get your Client ID from the Web3Auth Dashboard
  web3AuthNetwork: "sapphire_mainnet",
  usePnPKey: false, // Setting this to true returns the same key as PnP Web SDK, By default, this SDK returns CoreKitKey.
});

web3auth.init({ provider: privateKeyProvider });

const user = {
  id: "faj2720i2fdG7NsqznOKrthDvq43", // must be unique to each user
  name: "Mohammad Shahbaz Alam",
  email: "shahbaz@web3auth.io",
  profileImage: "https://avatars.githubusercontent.com/u/46641595?v=4",
};

const connect = async () => {
  const web3authNodeprovider = await web3auth.connect({
    verifier: "web3auth-sfa-verifier", // e.g. `web3auth-sfa-verifier` replace with your verifier name, and it has to be on the same network passed in init().
    verifierId: user.id, // e.g. `Yux1873xnibdui` or `name@email.com` replace with your verifier id(sub or email)'s value.
    idToken: jwt.sign(
      {
        sub: user.id, // must be unique to each user
        name: user.name,
        email: user.email,
        picture: user.profileImage,
        aud: "urn:my-resource-server", // -> to be used in Custom Authentication as JWT Field
        iss: "https://my-authz-server", // -> to be used in Custom Authentication as JWT Field
        iat: Math.floor(Date.now() / 1000),
        exp: Math.floor(Date.now() / 1000) + 60 * 60,
      },
      privateKey,
      { algorithm: "RS256", keyid: "1bb9605c36e69386830202b2d" },
    ), // or replace it with your newly created unused JWT Token.
  });
  const ethPrivateKey = await web3authNodeprovider.request({ method: "eth_private_key" });
  // The private key returned here is the CoreKitKey
  console.log("ETH Private Key", ethPrivateKey);
};
connect();
Note

One needs to re-initialize the SDK for each new user.

Provider JWT Example​

JWT Example
const { Web3Auth } = require("@web3auth/node-sdk");
const { EthereumPrivateKeyProvider } = require("@web3auth/ethereum-provider");

const privateKeyProvider = new EthereumPrivateKeyProvider({
  config: {
    chainConfig: {
      chainId: "0xaa36a7",
      rpcTarget: "https://rpc.ankr.com/eth_sepolia",
      displayName: "Ethereum Sepolia",
      blockExplorerUrl: "https://sepolia.etherscan.io/",
      ticker: "ETH",
      tickerName: "Ethereum",
    },
  },
});

// Instantiate Web3Auth Node.js SDK
const web3auth = new Web3Auth({
  clientId: "WEB3AUTH_CLIENT_ID", // Get your Client ID from the Web3Auth Dashboard
  web3AuthNetwork: "sapphire_mainnet",
  usePnPKey: false, // Setting this to true returns the same key as PnP Web SDK, By default, this SDK returns CoreKitKey.
});

web3auth.init({ provider: privateKeyProvider });

const connect = async () => {
  const web3authNodeprovider = await web3auth.connect({
    verifier: "web3auth-sfa-verifier", // e.g. `web3auth-sfa-verifier` replace with your verifier name, and it has to be on the same network passed in init().
    verifierId: "verifier-id-value", // e.g. `Yux1873xnibdui` or `name@email.com` replace with your verifier id(sub or email)'s value.
    idToken: "JWT Token", // or replace it with your newly created unused JWT Token you get from your auth provider.
  });
  const ethPrivateKey = await web3authNodeprovider.request({ method: "eth_private_key" });
  // The private key returned here is the CoreKitKey
  console.log("ETH Private Key", ethPrivateKey);
};
connect();
Note

One needs to re-initialize the SDK for each new user.