Sensitive data is encrypted at rest using platform-secure storage

AsyncStorage in React Native is unencrypted plaintext on every platform — its contents are readable from a jailbroken iOS device or from any app on Android versions below 4.4. Storing auth tokens, JWTs, or user PII in AsyncStorage means a single compromised device exposes session credentials that can be replayed to impersonate the user with full account access. OWASP 2021 A02 (Cryptographic Failures), CWE-312 (Cleartext Storage of Sensitive Information), HIPAA §164.312(a)(2)(iv), and NIST SP 800-218 PW.4 all require sensitive data at rest to be encrypted using platform-provided mechanisms (Keychain on iOS, Keystore on Android).

Replace AsyncStorage for sensitive data with expo-secure-store, which uses Keychain on iOS and EncryptedSharedPreferences on Android:

import * as SecureStore from 'expo-secure-store';

// Store
await SecureStore.setItemAsync('authToken', token);

// Retrieve
const token = await SecureStore.getItemAsync('authToken');

For non-Expo React Native, use react-native-keychain:

import * as Keychain from 'react-native-keychain';
await Keychain.setGenericPassword('token', jwtValue);

Search for every AsyncStorage.setItem call in src/ and audit what is being stored. Move tokens and PII to secure storage; leave only non-sensitive preferences (theme, language) in AsyncStorage.

• ID: sensitive-data-encryption
• Severity: high
• What to look for: Count all relevant instances and enumerate each. Look for sensitive data stored in unencrypted storage. The key risk: AsyncStorage (React Native) is plaintext and unencrypted — any data stored there is readable from a jailbroken/rooted device and accessible to other apps on older Android versions. Search for AsyncStorage.setItem calls that store: auth tokens, session tokens, refresh tokens, JWT, API keys, user PII (name, email, phone, address), health data, financial data, or any object stringified with JSON.stringify() containing these fields. Compare against encrypted alternatives: expo-secure-store (Keychain on iOS, EncryptedSharedPreferences on Android), react-native-keychain (Keychain on iOS, Keystore on Android), @react-native-async-storage/async-storage combined with rn-encrypted-storage. For Flutter, look for shared_preferences storing sensitive data vs. flutter_secure_storage. For native iOS, look for UserDefaults storing tokens vs. Keychain (SecItemAdd). Flag: auth tokens in AsyncStorage; raw JWTs stored in localStorage-equivalent; any string containing "token", "secret", "key", "password", "ssn", "creditCard" stored in plaintext storage.
• Pass criteria: Auth tokens and sensitive PII are stored in platform-secure encrypted storage (Keychain on iOS, Keystore on Android, or equivalent). At least 1 implementation must be verified. No tokens or credentials found in AsyncStorage or SharedPreferences.
• Fail criteria: Auth tokens, session keys, or sensitive PII stored in AsyncStorage, SharedPreferences, or equivalent unencrypted storage.
• Skip (N/A) when: App is stateless (no local data persistence) or has no sensitive data storage (no auth, no PII collection).
• Detail on fail: "JWT token stored via AsyncStorage.setItem('authToken', token) in src/services/auth.ts — AsyncStorage is unencrypted plaintext on all platforms" or "User profile including email and phone stored in AsyncStorage via JSON.stringify — sensitive PII in plaintext local storage"
• Remediation: Unencrypted token storage is exploitable on jailbroken/rooted devices and creates privacy liability.
  1. Replace AsyncStorage for sensitive data with expo-secure-store:

     import * as SecureStore from 'expo-secure-store';
     
     // Store
     await SecureStore.setItemAsync('authToken', token);
     
     // Retrieve
     const token = await SecureStore.getItemAsync('authToken');
     

  2. For non-Expo React Native, use react-native-keychain:

     import * as Keychain from 'react-native-keychain';
     await Keychain.setGenericPassword('token', jwtValue);
     

  3. Audit every AsyncStorage.setItem call — move tokens and PII to secure storage, leave only non-sensitive preferences (theme, language) in AsyncStorage