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Session Storage

This guide covers securely storing and restoring Privacy Boost sessions in React Native, expanding on the persistence options in Key Management.

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Storage Options

React Native offers several storage options with different security trade-offs:
StorageSecurityUse when
AsyncStorageLow (unencrypted)Development only
react-native-keychainHigh (OS keychain)Production apps

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Basic: AsyncStorage

The simplest approach, but AsyncStorage is unencrypted. Only suitable for development. 
import AsyncStorage from '@react-native-async-storage/async-storage';
import { PrivacyBoost } from '@sunnyside-io/privacy-boost-react-native';

const SESSION_KEY = 'privacy_boost_session';

// Save session
async function saveSession(sdk: PrivacyBoost) {
  const session = sdk.exportSession();
  if (session) {
    await AsyncStorage.setItem(SESSION_KEY, JSON.stringify(session));
  }
}

// Restore session
async function restoreSession(sdk: PrivacyBoost): Promise<boolean> {
  const stored = await AsyncStorage.getItem(SESSION_KEY);
  if (!stored) return false;

  try {
    const session = JSON.parse(stored);
    return sdk.importSession(session);
  } catch {
    await AsyncStorage.removeItem(SESSION_KEY);
    return false;
  }
}

// Clear session
async function clearSession(sdk: PrivacyBoost) {
  sdk.logout();
  await AsyncStorage.removeItem(SESSION_KEY);
}
For production apps, use react-native-keychain to store sessions in the platform’s secure storage (iOS Keychain / Android Keystore).

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Install

npm install react-native-keychain
cd ios && pod install

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Session Manager

import * as Keychain from 'react-native-keychain';
import { PrivacyBoost } from '@sunnyside-io/privacy-boost-react-native';

const SERVICE_NAME = 'com.yourapp.privacyboost';

async function saveSession(sdk: PrivacyBoost): Promise<void> {
  const session = sdk.exportSession();
  if (!session) return;

  await Keychain.setGenericPassword(
    'privacy-boost-session',
    JSON.stringify(session),
    { service: SERVICE_NAME }
  );
}

async function restoreSession(sdk: PrivacyBoost): Promise<boolean> {
  const credentials = await Keychain.getGenericPassword({ service: SERVICE_NAME });
  if (!credentials) return false;

  try {
    const session = JSON.parse(credentials.password);
    return sdk.importSession(session);
  } catch {
    await Keychain.resetGenericPassword({ service: SERVICE_NAME });
    return false;
  }
}

async function clearSession(sdk: PrivacyBoost): Promise<void> {
  sdk.logout();
  await Keychain.resetGenericPassword({ service: SERVICE_NAME });
}

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With Biometric Protection

Add Face ID / fingerprint requirement to access stored sessions: 
import * as Keychain from 'react-native-keychain';

async function saveSessionWithBiometrics(sdk: PrivacyBoost): Promise<void> {
  const session = sdk.exportSession();
  if (!session) return;

  await Keychain.setGenericPassword(
    'privacy-boost-session',
    JSON.stringify(session),
    {
      service: SERVICE_NAME,
      accessControl: Keychain.ACCESS_CONTROL.BIOMETRY_CURRENT_SET,
      accessible: Keychain.ACCESSIBLE.WHEN_UNLOCKED_THIS_DEVICE_ONLY,
    }
  );
}

async function restoreSessionWithBiometrics(sdk: PrivacyBoost): Promise<boolean> {
  try {
    const credentials = await Keychain.getGenericPassword({
      service: SERVICE_NAME,
      authenticationPrompt: {
        title: 'Unlock Privacy Boost',
        subtitle: 'Authenticate to access your private wallet',
      },
    });

    if (!credentials) return false;

    const session = JSON.parse(credentials.password);
    return sdk.importSession(session);
  } catch {
    // Biometric auth failed or was cancelled
    return false;
  }
}

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Check Biometric Availability

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

async function checkBiometrics(): Promise<string | null> {
  const biometryType = await Keychain.getSupportedBiometryType();
  // Returns: 'TouchID' | 'FaceID' | 'Fingerprint' | 'Iris' | null
  return biometryType;
}

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Usage in a React Native Component

import React, { useEffect, useState } from 'react';
import { View, Text, Button, ActivityIndicator } from 'react-native';
import { KeySource } from '@sunnyside-io/privacy-boost-react-native';

function PrivacyWallet({ sdk }: { sdk: PrivacyBoost }) {
  const [loading, setLoading] = useState(true);
  const [authenticated, setAuthenticated] = useState(false);

  useEffect(() => {
    // Try restoring session on mount
    restoreSessionWithBiometrics(sdk)
      .then((restored) => {
        setAuthenticated(restored);
        setLoading(false);
      })
      .catch(() => setLoading(false));
  }, []);

  if (loading) return <ActivityIndicator />;

  if (!authenticated) {
    return (
      <View>
        <Text>Not logged in</Text>
        <Button
          title="Connect Wallet"
          onPress={async () => {
            const result = await sdk.authenticate(
              walletDelegate,
              new KeySource.WalletDerived(),
              undefined,
            );
            if (result.tag === 'Authenticated') {
              await saveSessionWithBiometrics(sdk);
              setAuthenticated(true);
            } else if (result.tag === 'MnemonicGenerated') {
              // First-time user: show the recovery phrase, then continue.
              await sdk.proceedAfterMnemonic(undefined);
              await saveSessionWithBiometrics(sdk);
              setAuthenticated(true);
            }
            // CredentialRequired / RecoveryRequired handled elsewhere.
          }}
        />
      </View>
    );
  }

  return (
    <View>
      <Text>Privacy Address: {sdk.getPrivacyAddress()}</Text>
      <Button
        title="Logout"
        onPress={async () => {
          await clearSession(sdk);
          setAuthenticated(false);
        }}
      />
    </View>
  );
}

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iOS Configuration

Add Face ID usage description to ios/YourApp/Info.plist: 
<key>NSFaceIDUsageDescription</key>
<string>Authenticate to access your Privacy Boost wallet</string>

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Next Steps