How to integrate Firebase with Web3Auth iOS SFA SDK

In this guide, we'll talk about how we can use Web3Auth Single Factor Auth with Firebase in your iOS application.

As an overview, the guide is quite simple, with functionality to log in, display user details, and perform blockchain interactions. The signing of the blockchain transactions is done through the Web3Auth embedded wallet. You can check out the infrastructure docs, "Web3Auth Wallet Management Infrastructure" for a high-level overview of the Web3Auth architecture and implementation. For those who want to skip straight to the code, you can find it on GitHub.

How to set up Web3Auth Dashboard​

If you haven't already, sign up on the Web3Auth platform. It is free and gives you access to the Web3Auth's base plan. After the basic setup, explore other features and functionalities offered by the Web3Auth Dashboard. It includes custom verifiers, whitelabeling, analytics, and more. Head to Web3Auth's documentation page for detailed instructions on setting up the Web3Auth Dashboard.

How to set up Firebase for iOS​

If you haven't already setup the Firebase for your iOS app, please setup the Firebase, as it's the prerequisites for the guide. Head to the Firebase's documentation for the details instructions.

How to set up Custom verifier​

Once, you have set up the Web3Auth Dashboard, created a new project, and set up Firebase, it's time to create a Custom Verifier for your Firebase application. We already have detail instructions on how to create a Custom Verifier for Firebase, please head to our documentation.

Integrating Web3Auth SFA in iOS​

Once, you have set up the Custom Verifier, it's time to integrate Web3Auth in your iOS application. For the implementation, we'll use the "single-factor-auth-swift". This SDK facilitates integration with Web3Auth. This way you can easily manage embedded wallet in your iOS application.

Installation​

To install the single-factor-auth-swift package, you have two options. You can either use the Swift Package Manager, or you can install using Cocoapods.

pod 'SingleFactorAuth', '~> 6.0.0'

Initialization​

After successfully installing the package, the next step is to initialize SingleFactorAuth in your iOS app. This sets up the necessary configurations using Web3Auth network and prepares the SDK. Learn more about SingleFactorAuth Initialization.

var singleFactorAuth = SingleFactorAuth(
    singleFactorAuthArgs: .init(
        web3AuthClientId: "YOUR_WEB3AUTH_CLIENT_ID",
        network: Web3AuthNetwork.SAPPHIRE_MAINNET
    )
)

Session Management​

To check whether the user is authenticated, you can use the initialize method. For a user already authenticated, the result would be a non-nullable TorusSFAKey. You can navigate to different views based on the result.

if let torusKey = try await singleFactoreAuth.initialize() {
  print(torusKey.getPrivateKey())
  print(torusKey.getPublicAddress())
}

Authentication​

If the user is not authenticated, you should utilize the getKey method. For the guide, we will add Email Password login using Firebase. The getKey method is pretty straightforward in SingleFactorAuth and takes LoginParams as input. After successfully logging in, the method will return the TorusSFAKey.

Learn more about SingleFactorAuth LoginParams. To more about Firebase login methods, please checkout the Firebase documentation.

do {
    // Replace email and password with user's email and password
    let res = try await Auth.auth().signIn(withEmail: "ios@firebase.com", password: "iOS@Web3Auth")
    let id_token = try await res.user.getIDToken()

    // Replace with the verifier you created in Web3Auth Dashboard
    // for your project.
    let verifierName = "w3a-firebase-demo"

    let torusSFAKey = try await singleFactorAuth.getKey(
        loginParams: .init(
            verifier: verifierName,
            verifierId: res.user.uid,
            idToken: id_token
        )
    )
} catch {
    // Handle error
}

Set up Blockchain Providers​

Once we have successfully authenticated the user, the next step would be to fetch the user details, retrieve wallet address and prepare blockchain providers for interactions. For this guide, we are supporting only Ethereum ecosystem, but the general idea can be used for any blockchain ecosystem.

For interacting with ethereum chains, we'll use the web3.swift package. To install the single-factor-auth-swift package, you have two options. You can either use the Swift Package Manager, or you can install using Cocoapods.

pod 'web3.swift', '~> 1.6.1'

After successfully installing package, it's time to create an extension for TorusSFAKey which conforms to EthereumSingleKeyStorageProtocol.

extension TorusSFAKey: EthereumSingleKeyStorageProtocol {
    public func storePrivateKey(key: Data) throws {}

    public func loadPrivateKey() throws -> Data {
        guard let privKeyData = Data.init(hex: self.getPrivateKey()) else {
            return Data()
        }
        return privKeyData

    }
}

Once, we have created the extension, we will create EthereumAccount instance to retrive user's EOA address, and sign the transactions.

let ethereumAccount = try! EthereumAccount(
  keyStorage: torusSFAKey as EthereumSingleKeyStorageProtocol
)

let address = ethereumAccount.address

To retrive user's balance, and interacting with Blockcahin, you can follow our detailed guide on how to interact with EVM chain guides. To interact with Solana blockchain, you can checkout our Solana blockchain guide.

Conclusion​

Voila, you have learned how to use Web3Auth SFA SDK with iOS application.

If you are interested in learning more about SFA SDK, please checkout our documentation for iOS SFA SDK. You can find the code used for the guide on our examples repo.