How flutter secure storage plugin stores the key in both android and iOS ?

Flutter Secure Storage Plugin

flutter_secure_storage uses platform-specific secure storage:

Android Implementation

Uses Android Keystore (hardware-backed when available):

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// Under the hood - Android code
KeyStore keyStore = KeyStore.getInstance("AndroidKeyStore");
keyStore.load(null);
SecretKey key = (SecretKey) keyStore.getKey("key_alias", null);

Process:

1. Data encrypted with AES key
2. Key stored in AndroidKeystore
3. Key protected by device lock screen
4. Hardware acceleration if available

iOS Implementation

Uses iOS Keychain:

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// iOS Keychain - secure by default
SecurityClass: kSecClassGenericPassword
AccessibleAttribute: kSecAttrAccessibleWhenUnlockedThisDeviceOnly

Process:

1. Data encrypted and stored in Keychain
2. Protected by device passcode
3. Hardware-backed on modern devices
4. Requires authentication to access

Comparison

Usage

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final storage = FlutterSecureStorage();

await storage.write(key: 'token', value: 'secret_token');
final token = await storage.read(key: 'token');
await storage.delete(key: 'token');

Security: Both methods are cryptographically secure.