Privacy Policy - Ulertu

1. Overview and Scope

Ulertu is an educational spreadsheet diagnostic application developed by Saifullah Ahad. It helps students, teachers, and spreadsheet learners understand how formulas evaluate and how cell values depend on each other.

Users can explore built-in sample workbooks or open their own OpenXML spreadsheet files (.xlsx, .xlsm). Ulertu analyzes formula dependencies locally on the device to create targeted prediction questions: if an input cell value were altered, how does a formula result cell change? Users test their reasoning and step through the full calculation trace.

2. Records Kept on Your Device

Ulertu requires no user account, sign-in, username, password, or contact information. All data processed by Ulertu is stored exclusively in the application's private internal storage directory on your phone:

• Imported Workbooks: When you open a spreadsheet through the system file picker or via the "Open with" or share intent from another app, a working copy is saved directly into the app's private files directory (files/workbooks/) under a filename derived from its cryptographic SHA-256 hash. Standard Android file-sandbox boundaries prevent other installed applications from reading this private directory.
• On-Device Database: An SQLite database (ulertu.db) keeps records of your workbooks and diagnostic checks:
  • Workbook records: the display name, local file path, file size in bytes, SHA-256 hash, chronological sequence order, and check counts.
  • Evidence records: the tested formula cell, formula expression, input cell that was changed, original and modified values, prediction prompt, available answer choices, your recorded answers, whether your prediction was correct on the first attempt, follow-up attempts, and step-by-step calculation trace chains.

Ulertu does not transmit workbook contents, formula structures, or quiz responses across a network.

3. Device Permissions and Network Behavior

• No Internet Permission: Ulertu does not declare the android.permission.INTERNET or android.permission.ACCESS_NETWORK_STATE permissions in its Android manifest. The application cannot establish network connections, transmit telemetry, or contact remote servers.
• No Dangerous Permissions: Ulertu requests no access to device location, camera, microphone, contacts, call logs, calendar, SMS, physical activity sensors, or shared storage.
• System File Selection: Opening a workbook uses the standard Android Storage Access Framework (SAF) and system intent mechanism. Ulertu receives temporary read access only to the single file you select.
• Android Backup Excluded: Ulertu configures android:allowBackup="false" in its manifest. Your local workbook copies and diagnostic evidence records are not uploaded to Google Drive or transferred to cloud backup services by the operating system.

4. Advertising, Analytics, and Third-Party Services

Ulertu contains no advertising SDKs, no behavioral tracking, no third-party analytics libraries, and no crash-reporting services. The application does not collect, profile, sell, or share personal data with any third party.

5. Retention and Deletion of Data

All imported workbooks, check counts, and diagnostic history stay on your phone until you delete them:

• Deleting a Single Workbook: In the "Your workbooks" list, selecting "Delete" on any workbook immediately erases that workbook file from internal storage and permanently deletes its record and all associated evidence history from the database.
• Deleting All Workbooks: Selecting "Delete all" removes every imported workbook file and clears all check history from the database.
• Removing the Application: Uninstalling Ulertu or clearing the application's storage in Android Settings (Settings > Apps > Ulertu > Storage > Clear Storage) immediately and permanently removes all stored workbooks, databases, and configuration files from your device.

6. Children's Privacy

Ulertu is designed for secondary-school students and spreadsheet learners of all ages. Because the application requires no registration, requests no network permissions, and processes all spreadsheets strictly on the device without transmitting data externally, it does not collect personal information from children or any other user.

7. Updates to This Policy

If features or technical behaviors in Ulertu change, this privacy policy will be updated accordingly. The effective date at the top of this document indicates when the latest revision took effect.

8. Contact Information

For questions or inquiries regarding this privacy policy or the application: