1. Introduction
SheetLock ("we", "us", "the App") is a private, offline-first spreadsheet application for Android developed by Nchitimilla. This Privacy Policy explains what data the App collects, how it is used, and your rights.
2. Data We Collect
2.1 Data Stored Locally on Your Device
- Spreadsheet data: All workbook content (cells, formulas, formatting, charts) is stored exclusively on your device using an encrypted local database (Room + SQLCipher). We never transmit your spreadsheet data to any server.
- User preferences: Settings such as theme choice, auto-lock timeout, and PIN/biometric configuration are stored in Android EncryptedSharedPreferences on your device.
- Encrypted backups: If you use the cloud backup feature, backup files are encrypted with AES-256 on your device before export. The encryption key never leaves your device.
2.2 Data Collected by Third-Party SDKs
- Google AdMob: For free-tier users, the App displays ads via Google AdMob. AdMob may collect device identifiers (Advertising ID), IP address, and interaction data to serve personalised or contextual ads. The App uses the Google User Messaging Platform (UMP) to obtain your consent before serving personalised ads, in compliance with GDPR and CCPA. You can change your ad privacy preferences at any time from Settings > Ad Privacy Options. See Google's Privacy Policy.
- Google Play Billing: When you purchase SheetLock Pro, the transaction is processed by Google Play. We receive a purchase token and timestamp but do not access your payment details. See Google's Privacy Policy.
- Google Play In-App Updates: The App checks for available updates via the Play Core library. This sends your app version to Google's servers. No personal data is shared.
2.3 Data We Do NOT Collect
- We do not collect your name, email address, phone number, or location.
- We do not operate servers that receive your spreadsheet content.
- We do not use analytics SDKs or crash-reporting services that transmit personal data.
3. Permissions
- INTERNET: Required for displaying ads (free tier), processing in-app purchases, and checking for app updates.
- USE_BIOMETRIC: Required to offer biometric (fingerprint/face) unlock as an alternative to PIN entry.
- AD_ID: Used by Google AdMob to serve ads. You may opt out of personalised ads via the in-app Ad Privacy Options (Settings) or your device's ad settings.
- POST_NOTIFICATIONS: Used to display save-complete or backup-complete notifications. You may deny this permission at any time.
4. Data Security
- All spreadsheet data is encrypted at rest using SQLCipher.
- Preferences are stored in EncryptedSharedPreferences (AES-256).
- Cloud backup files are encrypted with AES-256-GCM before leaving the device.
- Optional screenshot prevention (FLAG_SECURE) blocks screen capture of sensitive data.
- PIN and biometric locks prevent unauthorised access to the App.
5. Data Retention & Deletion
All user data is stored locally. Uninstalling the App removes all data. You may also delete individual workbooks or clear all data from within the App's settings.
6. Children's Privacy
The App is not directed at children under the age of 13. We do not knowingly collect personal information from children.
7. Your Rights
Because your data is stored entirely on your device, you have full control. You can export, delete, or back up your data at any time. To opt out of personalised ads, use the Ad Privacy Options in the App's settings or adjust your device's advertising settings.
8. Changes to This Policy
We may update this Privacy Policy from time to time. The "Last updated" date at the bottom reflects the most recent revision. Continued use of the App after changes constitutes acceptance.
9. Contact
If you have questions about this Privacy Policy, contact us at nagaraju.chitimilla@gmail.com.
Last updated: March 10, 2026