Hengdeng Math Privacy Policy

1. Data Collection and Synchronization

Hengdeng Math (Version 2.3.0) runs primarily as a local application and also offers optional iCloud synchronization. The app does not collect your name, email address, contact information, or device location.

2. Subscription and Payment Processing

This app provides subscription services through the Apple App Store. All payment processing is handled by Apple; we do not collect or store your payment information (such as credit card numbers, payment passwords, etc.).

When purchasing a subscription, the App Store provides transaction records, and we only receive anonymous subscription status information (e.g., validity, expiration date) via the RevenueCat service to provide subscription features. We do not associate your purchase information with personal identity information.

3. Data Storage

All user-created data is stored by default in the local SQLite database on your device. When you enable iCloud synchronization, data will be securely stored in your iCloud account via Apple's CloudKit service.

Uninstalling the app will delete locally stored data, but data already synced to iCloud will be retained according to your iCloud settings.

4. iCloud Data Management

You can toggle iCloud functionality in the app's settings page, or fully control iCloud synchronization through your device's system settings:

After disabling iCloud synchronization, new data will only be stored locally, and data already synced to iCloud will remain in your iCloud account. You can manage this data via iCloud.com.

5. Photo Library Access

The app only requests access to your photo library in the following scenarios:

• When you choose to export geometric figures as images to save to the photo library
• When you choose to import images from the photo library into the app

Images uploaded to the app are stored by default in the user's local SQLite database; if iCloud synchronization is enabled, these images will also be securely synced to your iCloud account.

6. Subscription Management

You can manage your subscription through Apple's subscription management system:

You can cancel your subscription at any time; after cancellation, the subscription will remain valid until the end of the current cycle, after which it will automatically downgrade to the free version. The free version still allows use of basic features, but some advanced features will be restricted.

7. Data Security

We attach great importance to your data security:

• Local data is encrypted and stored on the device
• iCloud data transmission and storage are protected by Apple's encryption technology
• The app contains no ads or analytics tracking, and no third-party SDKs access your data
• Subscription information is processed through Apple and RevenueCat's secure services

8. Children's Privacy

This app is suitable for users of all ages, but we pay special attention to children's privacy:

Children under 13 should use this app under parental guidance, and parents can manage children's iCloud synchronization and subscription purchases through system settings (using Family Sharing purchase features).

9. Third-Party Services

This app uses the following third-party services:

• RevenueCat: For managing subscription status; does not collect personal identity information
• Apple CloudKit: For iCloud data synchronization
• Apple App Store: For processing subscription payments

Each of these services has its own privacy policy, and we recommend reviewing the relevant service's privacy terms.

10. Policy Updates

We may occasionally update this privacy policy to reflect feature changes. The updated policy will be prominently displayed within the app with a new update date.