saveEncryptedData static method
Save encrypted content to file
Implementation
static Future<void> saveEncryptedData(String content, String passphrase) async {
final salt = _generateSalt();
final iv = _generateIV();
final key = await _deriveKey(passphrase, salt);
final encrypted = await _encrypt(content, key, iv);
final payload = jsonEncode({
'salt': base64Encode(salt),
'iv': base64Encode(iv),
'data': base64Encode(encrypted),
});
final filePath = await _getPublicDocumentsPath();
final file = File(filePath);
await file.writeAsString(payload);
}