What is FlutterSecureStorage?

flutter_secure_storage stores sensitive data using the platform's secure storage mechanisms: iOS Keychain and Android Keystore (via EncryptedSharedPreferences on API 23+). Data is encrypted at rest and protected by the device's hardware security module where available. Use it for authentication tokens, refresh tokens, PINs, and passwords — any data that would be a security risk if accessed from a compromised or rooted device. Never use SharedPreferences or Hive for sensitive credentials, as they store data unencrypted.