How to implement Secure Storage in Flutter? | AppSec Articles
One distinction that trips people up: flutter_secure_storage is built for small secrets, not for your app’s data.
Keep the encryption key there, and keep the records in sqflite, encrypted either per field or with SQLCipher for the whole file. Per-field encryption leaves non-sensitive columns queryable; SQLCipher is simpler when everything is sensitive. Either way, generate the key on the device rather than shipping it in code.
Here’s how we applied this in a password vault app: https://www.mindstacklabs.com/case-studies/6