Privacy Policy for HashCalc

1. Introduction

HashCalc ("the App") is a professional cryptographic hashing and checksum toolkit developed by AntoTech ("we," "us," or "our"). This Privacy Policy explains how we handle your information when you use the App.

The App is designed to generate, verify, and compare cryptographic hashes and checksums (MD5, SHA-1, SHA-224, SHA-256, SHA-384, SHA-512, SHA3-256, SHA3-512, RIPEMD-160, and CRC32), including HMAC-based message authentication. Key features include single-file and batch hashing, text hashing, checksum manifest verification (.sfv, .sha256sums, and similar formats), remote URL hashing, a mathematical integrity audit (Shannon entropy analysis), exportable PDF reports, and an optional Pro upgrade that removes ads and unlocks advanced features.

We are committed to protecting your privacy. The App operates on a Privacy-by-Design principle: your files and text data are processed locally on your device and are never collected, stored, or transmitted to our own servers, with the single exception described in Section 2(A) below regarding remote URL hashing.

2. Information We Collect

A. Information You Provide (Processed Locally)

•      File Data: Content of files you select for hashing (single file or batch). These are processed in chunks using a local background Web Worker to ensure performance and privacy.

•      Text Content: Strings typed or pasted for conversion into hash or HMAC values.

•      Comparison Data: Hashes provided by the user to verify against generated results, including checksum manifest files (.sfv, .sha256sums, and similar) you choose to import.

•      Shared Files: If you use your device’s "Share" menu to send a file to the App from another app (e.g., a file manager), that file is processed the same way as a file you select manually — locally, on your device.

•      Remote URL Hashing (exception to local-only processing): If you choose to hash a file located at a remote URL, the App relays that request through a secure proxy server we operate (hosted on Cloudflare) in order to retrieve the file, because browsers do not allow the App to download arbitrary remote files directly. The proxy server fetches the requested URL and streams the file back to your device; it does not store, log, or retain the file content, and the resulting hash is still calculated locally on your device. We recommend only hashing URLs you trust.

Note: Outside of the remote URL exception above, all processing occurs strictly within your device’s local environment. We do not have access to your files or the text you hash.

B. Automatically Collected Information

•      Device & Usage Data: Non-personal information such as device model, operating system, and app version may be processed by the underlying framework (Cordova/Web) to ensure compatibility.

•      Version Checks: The App fetches a secure remote file (GitHub Gist) to notify you of critical updates and ensure you are running the latest, most secure version.

•      Local History: The App may keep a local history of your recent hash operations (limited to your last 10 entries on the free tier, or 50 with HashCalc Pro) to make it easier to revisit or export past results. This history is stored only on your device and can be cleared at any time from Settings (see Section 7).

C. Third-Party Services

•      Advertising (Google AdMob): Free-tier users see ads to keep the App free of charge. AdMob may collect identifiers (e.g., Advertising ID), IP addresses, and usage data to serve relevant ads. Where required by applicable law (e.g., for users in the European Economic Area and UK), the App uses Google’s User Messaging Platform (UMP) to request your consent before showing personalized ads, and you may review or withdraw that consent at any time. Please refer to Google’s Privacy Policy (policies.google.com/privacy) for details. Users who purchase HashCalc Pro do not see ads.

•      In-App Purchases (Google Play Billing): HashCalc Pro is an optional one-time purchase processed entirely through Google Play Billing. We do not collect, see, or store your payment card details or billing address — that information is handled directly by Google. We only receive confirmation of whether a purchase was completed, which we use to unlock Pro features on your device.

•      Optional Hash Lookup (VirusTotal): If you tap the optional "Check on VirusTotal" link on a result, the App opens VirusTotal’s public website in your browser and includes only the hash value (never the file itself, and never any of its content) in that page’s address. This only happens if you explicitly tap that link. Please refer to VirusTotal’s Privacy Policy for details on how they handle that request.

3. How We Use Your Information

•      App Functionality: To generate accurate cryptographic hashes and HMAC values, and to perform real-time comparisons, including in batch and checksum-manifest-verification workflows.

•      Technical Audit: To provide mathematical insights (Shannon entropy and known-algorithm-weakness flags) calculated locally.

•      Update Monitoring: To notify you of new features or security patches via the version check system.

•      Purchase Management: To recognize and restore your HashCalc Pro purchase across reinstalls, via Google Play Billing.

•      Maintenance: To improve app performance and fix technical bugs.

We do not sell, rent, or trade your data or hash results to third parties.

4. Data Storage and Security

•      Local Processing: All sensitive data (the content you hash) stays on your device. We do not use cloud synchronization for your hashes, history, or settings, to ensure total data sovereignty.

•      Remote URL Proxy: As described in Section 2(A), files fetched from a remote URL you provide pass through our proxy server only to retrieve them; they are not stored or logged there.

•      User Responsibility: Since data is local, you are responsible for maintaining the security of your device. Clearing app cache/storage, or using the in-app "Clear All Data" option, will remove your saved settings and history (this does not affect your HashCalc Pro purchase, which is tied to your Google Play account and can be restored at any time).

5. Permissions

The App may request the following permissions:

•      Storage/Files: To read and process the files you choose to hash, verify, or share into the App.

•      Internet: To perform version checks, hash remote URLs you provide, display ads, and process HashCalc Pro purchases.

•      Haptic Feedback (Vibration): To provide confirmation when copying hashes or identifying a match.

•      In-App Billing: To process the optional HashCalc Pro purchase through Google Play.

6. Children’s Privacy

The App is a professional/technical tool not intended for unsupervised use by children under 13. We do not knowingly collect personal information from children. In-app purchases require an adult with a valid Google Play payment method.

7. Your Rights and Choices

•      Data Control: You can use the "Clear All Data" option in Settings at any time to erase all locally stored history and settings.

•      Restore Purchases: If you reinstall the App or switch devices, you can restore your HashCalc Pro purchase at any time from Settings, at no additional cost.

•      Opt-Out: You can stop all data processing by uninstalling the App. You may also opt out of personalized ads through your device’s privacy settings, through the consent management flow described in Section 2(C), or by purchasing HashCalc Pro to remove ads entirely.

8. Changes to This Policy

We may update this Privacy Policy to reflect changes in our App or legal requirements. Your continued use of the App constitutes acceptance of any changes.

9. Contact Us

If you have any questions or concerns regarding this Privacy Policy, please contact us at:

📧 Email: tech.anto19@gmail.com