Wallet Pregeneration

Para’s Wallet Pregeneration feature allows you to create wallets for users before they authenticate, giving you control over when and how users claim ownership of their wallets. This is particularly powerful in mobile applications, where you can leverage device-specific storage capabilities for enhanced user experiences.

Mobile-Specific Benefits

While pregeneration works the same across all Para SDKs, React Native and Expo applications offer unique advantages:

Pregeneration is especially valuable for devices that may not have full WebAuthn support for passkeys. It allows you to create Para wallets for users on any device while managing the security of the wallet yourself.

Creating a Pregenerated Wallet

Check if a wallet exists

import { para } from '../your-para-client';

async function checkPregenWallet() {
  const hasWallet = await para.hasPregenWallet({
    pregenId: { email: "user@example.com" },
  });
  
  return hasWallet;
}

Create a pregenerated wallet

import { para } from '../your-para-client';
import { WalletType } from '@getpara/react-native-wallet';

async function createPregenWallet() {
  const pregenWallet = await para.createPregenWallet({
    type: 'EVM', // or 'SOLANA', 'COSMOS', 'STELLAR'
    pregenId: {email: "user@example.com" },
  });
  
  console.log("Pregenerated Wallet ID:", pregenWallet.id);
  return pregenWallet;
}

import { para } from '../your-para-client';

async function getUserShare() {
  const userShare = await para.getUserShare();
  // Store this share securely
  return userShare;
}

Mobile Storage Options

In mobile applications, you have several options for securely storing the user share:

Keychain/Keystore
MMKV

import * as Keychain from 'react-native-keychain';

// Store the user share
async function storeUserShare(userShare) {
  try {
    await Keychain.setGenericPassword(
      'para_user_share',
      userShare,
      {
        service: 'com.yourapp.wallet',
        accessible: Keychain.ACCESSIBLE.WHEN_UNLOCKED_THIS_DEVICE_ONLY
      }
    );
  } catch (error) {
    console.error("Error storing user share:", error);
  }
}

// Retrieve the user share
async function retrieveUserShare() {
  try {
    const credentials = await Keychain.getGenericPassword({
      service: 'com.yourapp.wallet'
    });
    
    if (credentials) {
      return credentials.password;
    }
    return null;
  } catch (error) {
    console.error("Error retrieving user share:", error);
    return null;
  }
}

import { MMKV } from 'react-native-mmkv';

// Initialize with encryption for better security
const storage = new MMKV({
  id: 'wallet-storage',
  encryptionKey: 'your-secure-encryption-key'
});

// Store the user share
function storeUserShare(userShare) {
  storage.set('user_share', userShare);
}

// Retrieve the user share
function retrieveUserShare() {
  return storage.getString('user_share');
}

Whichever storage method you choose, ensure you implement proper security measures. The user share is critical for wallet access, and if lost, the wallet becomes permanently inaccessible.

Using Pregenerated Wallets in Mobile Apps

Once you have created a pregenerated wallet and stored the user share, you can use it for signing operations:

import { para } from '../your-para-client';

async function usePregenWallet() {
  // Retrieve the user share from your secure storage
  const userShare = await retrieveUserShare();
  
  if (!userShare) {
    console.error("User share not found");
    return;
  }
  
  // Load the user share into the Para client
  await para.setUserShare(userShare);
  
  // Now you can perform signing operations
  const messageBase64 = btoa("Hello, World!");
  const signature = await para.signMessage({
    walletId: "your-wallet-id",
    messageBase64,
  });
  
  return signature;
}

Mobile-Specific Use Cases

Device-Specific Wallets

Create wallets that are bound to a specific device by using device-specific identifiers combined with secure local storage. This approach is ideal for multi-device users who need different wallets for different devices.

import DeviceInfo from 'react-native-device-info';

async function createDeviceWallet() {
  const deviceId = await DeviceInfo.getUniqueId();
  
  const pregenWallet = await para.createPregenWallet({
    type: 'EVM',
    pregenId: { customId: `device-${deviceId}` },
  });
  
  // Store the user share in device-specific secure storage
  const userShare = await para.getUserShare();
  await storeUserShare(userShare);
  
  return pregenWallet;
}

App Clips and Instant Experiences

For iOS App Clips or Android Instant Apps, create temporary wallets that enable limited blockchain functionality without requiring full app installation or user authentication.

async function createTemporaryWallet() {
  // Generate a random identifier for this session
  const sessionId = Math.random().toString(36).substring(2, 15);
  
  const pregenWallet = await para.createPregenWallet({
    type: 'EVM',
    pregenId: { customId: `temp-${sessionId}` },
  });
  
  const userShare = await para.getUserShare();
  
  // Store in memory for this session only
  // (could also use temporary secure storage)
  sessionStorage.userShare = userShare;
  
  return pregenWallet;
}

Transparent Web3 Integration

Seamlessly introduce blockchain functionality to your existing app users without requiring them to understand wallets or crypto.

async function createWalletForExistingUser(userId) {
  // Check if we already created a wallet for this user
  const hasWallet = await para.hasPregenWallet({
    pregenId: { customId: `user-${userId}` },
  });
  
  if (!hasWallet) {
    const pregenWallet = await para.createPregenWallet({
      type: 'EVM',
      pregenId: { customId: `user-${userId}` },
    });
    
    const userShare = await para.getUserShare();
    await storeUserShare(userShare);
    
    return pregenWallet;
  } else {
    // Retrieve existing wallet info
    const wallets = await para.getPregenWallets({
      pregenId: { customId: `user-${userId}` },
    });
    
    return wallets[0];
  }
}

Claiming Pregenerated Wallets

When a user is ready to take ownership of their pregenerated wallet, they can claim it once they’ve authenticated with Para:

import { para } from '../your-para-client';

async function claimWallet() {
  // Ensure user is authenticated
  if (!(await para.isFullyLoggedIn())) {
    console.error("User must be authenticated to claim wallets");
    return;
  }
  
  // Retrieve and load the user share
  const userShare = await retrieveUserShare();
  await para.setUserShare(userShare);
  
  // Claim the wallet
  const recoverySecret = await para.claimPregenWallets();
  
  // Optionally, clear the locally stored user share after claiming
  // since Para now manages it through the user's authentication
  await clearUserShare();
  
  return recoverySecret;
}

After claiming, Para will manage the user share through the user’s authentication methods. You can safely remove the user share from your local storage if you no longer need to access the wallet directly.

Best Practices for Mobile

Utilize Device Security: Leverage biometric authentication (TouchID/FaceID) to protect access to locally stored user shares.
Implement Device Sync: For users with multiple devices, consider implementing your own synchronization mechanism for user shares across devices.
Handle Offline States: Mobile applications often work offline. Design your pregenerated wallet system to function properly even when connectivity is limited.
Backup Strategies: Provide users with options to back up their wallet data, especially for device-specific wallets that might not be associated with their Para account.
Clear Security Boundaries: Clearly communicate to users when they’re using an app-managed wallet versus a personally-owned wallet.

​Mobile-Specific Benefits

​Creating a Pregenerated Wallet

​Check if a wallet exists

​Create a pregenerated wallet

​Retrieve the user share

​Mobile Storage Options

​Using Pregenerated Wallets in Mobile Apps

​Mobile-Specific Use Cases

​Claiming Pregenerated Wallets

​Best Practices for Mobile

​Related Resources

Mobile-Specific Benefits

Creating a Pregenerated Wallet

Check if a wallet exists

Create a pregenerated wallet

Retrieve the user share

Mobile Storage Options

Using Pregenerated Wallets in Mobile Apps

Mobile-Specific Use Cases

Claiming Pregenerated Wallets

Best Practices for Mobile

Related Resources