Privacy Policy

1Who we are

Zarvel is a backgammon and tavla game for Android, developed by Zydeno. You play matches against a computer opponent at five levels, and a coach reviews your decisions, explains mistakes in words, and offers lessons and practice. This policy explains what the app keeps on your phone, how the sealed dice ledger works, how backups work, and what happens if you choose to contact us at [email protected].

2What this policy covers

This policy covers the Zarvel Android app. It does not cover Android’s file picker, the document or cloud storage providers you save files to, or the browser and e-mail app you use. Their own terms and privacy policies govern the data you give them.

The app works without an account or an internet connection. The app has no ads and no analytics.

3What the developer does not collect

The app does not send the developer your games, moves, dice, scores, match history, coach analyses, lesson progress, saved mistakes, positions you set up, backup files, settings or device information. It has no account registration, no advertising SDK, no analytics SDK and no third-party crash reporter. It does not request internet, location, camera, microphone, contacts, phone, notification, photo-library or storage access.

We do not receive, sell or share your in-app data, use it for advertising or train models on it. Zarvel never asks for your name or contact details, and there is no online play, chat or leaderboard.

4What is stored on your phone

Zarvel keeps its working data in Android app-private storage (files and a preferences store). Depending on how you use the app and on the features in your version, this includes:

• Matches and games: the rule set (backgammon or tavla), match length, opponent level, the date and time, every move, the dice rolls, doubling-cube actions, the score and the result.
• Sealed dice records: for each game played with the app’s dice, the random key, its seal and the record of rolls used (see The sealed dice ledger).
• Coach and review: the analysis of your decisions, mistake marks, explanations, error rates and the dice statistics shown in the ledger.
• Learning: lesson and chapter progress, your answers, the skill map, the mistakes saved for later practice and when they are due again, and results of daily positions and drills.
• Positions you set up in the position editor, and games you enter with physical dice from a real board.
• Settings: language, each unit and format choice, theme, board options, default rules and match length, opponent level, coach options, sound and haptics.

All play, analysis, explanations, statistics and file generation run on your phone. This data is removed when you uninstall the app or clear its storage. It is information about how you play a board game; it does not include your name, contacts, location or identifiers we can use to recognise you.

5The sealed dice ledger

When a game uses the app’s dice, Zarvel creates a random key on your phone before the first move and saves it in the app’s private storage. The rolls of that game are derived from this key. Before the first move, the app shows a short fingerprint of the key, called the seal. When the game ends, the app shows the key and works out every roll again from it, so you can check that the rolls played match the seal shown at the start.

• Local only. The key, the seal, the record of rolls and the check all stay on your phone. They are not sent to the developer or to anyone else.
• Not about you. The key is random data. It is not derived from your identity, your device identifiers or your location, and it is not used to recognise you.
• Levels do not change the dice. The opponent’s level affects only how well the computer plays.
• Physical dice. Rolls you type in from a real board are not sealed and are left out of the dice ledger.

The technical details and the limits of what this check shows are described in the Terms of Use.

6The opponent and the coach

The computer opponent, the coach, the move analysis, the explanations and the cube advice are produced on your phone by Zydeno’s own engine and neural networks, which are bundled in the app. The networks were trained by Zydeno before release using games the program played against itself. Your games are not used to train them, are not uploaded and are not shared.

The skill map, the mistakes chosen for practice and the lessons suggested to you are worked out locally from your own games, only to help you learn. This is not profiling in the legal sense: nobody but you sees it, and it has no effect on you outside the app.

7No internet access from the app

The current Android app does not declare the INTERNET permission. It has no backend, no external API requests, no automatic uploads, no remote downloads and no cloud synchronisation. The engine, networks, tables, lessons, fonts and sounds are bundled in the app.

Links. When you open this policy, the Terms or the support e-mail address, the app hands the address to your own browser or e-mail app. Your browser then visits the site, and the website host can process ordinary web-request data such as your IP address under its own policy. Nothing is sent by Zarvel itself, and a support e-mail is sent only if you choose to send it.

8Backup, import and files

Export. Settings, Your data, Export data creates one backup file with your matches, games, learning progress, saved mistakes and settings. The file is created only when you tap Export, and it is saved where you choose in Android’s file picker. It is an ordinary file that Zarvel does not password-protect. If a game is unfinished, the file also contains that game’s dice key, so anyone who opens the file could read the remaining rolls of that game.

Import. Import data reads only the file you select in Android’s file picker. The app checks it on the phone and then replaces the current data with the contents of the file; you can undo the import straight away. No storage permission is needed.

Your destination matters. A cloud drive, e-mail app or other place you save the file to keeps it under its own policy. This is a transfer you start, not automatic synchronisation. Zydeno receives no copy unless you deliberately send one to support.

9Permissions and device access

Zarvel requests no runtime permissions. It does not request internet, location, camera, microphone, contacts, phone, notification, photo or media, storage-wide, all-files, Bluetooth, exact-alarm or Accessibility-service access, and it runs no foreground service. Android adds an app-scoped internal permission used by its support libraries; it does not grant access to your personal files or sensors. The advertising-ID permission is removed from the app.

Region. To choose sensible default time and date formats and number style, the app reads your device’s region locally: the country reported by your SIM or network through Android’s standard telephony information (no permission is needed, and no phone number or SIM identity number is read) and the region of your system language. This value is used on the device only and is not transmitted. You can change every format in Settings.

Sound and haptics. The app plays its own bundled sounds and uses the phone’s haptic feedback on game actions. Both can be switched off in Settings, and sound follows the phone’s volume and silent mode. The app sends no notifications.

10Your controls, backups and deletion

You can change every setting, export a backup, and use Settings, Your data, Delete all data to remove all matches, games, learning progress, saved mistakes and settings after you confirm. Export a backup first if you want to keep your data.

Automatic Android backup is disabled, and the app’s data-extraction rules exclude both cloud backup and device-to-device transfer. To move your data to another phone, export a backup and import the file yourself. If the phone is lost or the app’s storage is cleared without a backup, the developer cannot restore your data.

Uninstalling Zarvel or clearing its storage in Android Settings removes its private data. Deleting data in the app does not delete backup files you exported or copies you gave to others; remove those separately.

11Legal bases for processing

Where the EU or UK GDPR, or a similar law such as the Swiss FADP or Brazil’s LGPD, applies, these are the legal bases for the limited processing described in this policy:

The app makes no automated decisions that have legal or similarly significant effects on you, does not build a profile of you and does not process special categories of personal data. The coach’s view of your play stays on your device under your control, and the developer receives none of it.

12How long information is kept

Matches, games, dice records, learning progress and settings stay on your phone until you delete them, clear the app’s storage or uninstall the app. Deleting data is not a guarantee of forensic erasure of every byte on the device.

Backup files you saved outside the app remain under your control and may outlast uninstallation.

13Your privacy rights

Privacy laws in many countries give you rights over your personal data. Because Zarvel keeps your data on your phone and the developer does not receive it, most of these rights are in your own hands: you can view, export and delete everything in the app (§10). For data you have sent us, such as e-mails, write to [email protected].

EU and UK representative. The individual developer does not process personal data of people in the EU/EEA or the UK except occasional e-mails you choose to send to support. This occasional processing does not involve large-scale processing of special-category or criminal-offence data and is unlikely to result in a risk to your rights and freedoms. Under Article 27(2)(a) GDPR and Article 27(2)(a) UK GDPR, it does not require an EU or UK representative, so none is appointed. Contact us directly at [email protected]; you can also complain to your local supervisory authority.

Rights by region. A summary; the law where you live decides the details.

• European Union, EEA, United Kingdom and Switzerland (GDPR, UK GDPR, Swiss FADP): access, rectification, erasure, restriction of processing, data portability, objection to processing based on legitimate interests, withdrawal of consent at any time, and complaint to a supervisory authority, for example in the country where you live or work (in the UK, the Information Commissioner’s Office).
• United States (California CCPA as amended by the CPRA, and the comprehensive privacy laws of other states such as Virginia, Colorado, Connecticut, Texas and Oregon): to know and access, delete, correct and port personal information; to opt out of its sale or sharing, of targeted advertising and of profiling; to limit the use of sensitive personal information; to appeal a refusal; to use an authorised agent; and not to be discriminated against for using these rights. Notice for California residents: in the last 12 months the developer has not collected personal information through the app, other than e-mails you chose to send us. We have not sold or shared personal information, and we do not use sensitive personal information. Global Privacy Control signals are honoured where the law requires; today there is nothing to opt out of.
• Canada (PIPEDA and provincial laws, including Québec’s Law 25): access, correction and withdrawal of consent; complaints to the Office of the Privacy Commissioner of Canada or, in Québec, the Commission d’accès à l’information.
• Brazil (LGPD): confirmation of processing, access, correction, anonymisation, blocking or deletion, portability, information about sharing and revocation of consent; complaints to the ANPD.
• Japan (APPI): disclosure, correction, suspension of use or deletion; complaints to the Personal Information Protection Commission.
• South Korea (PIPA): access, correction, deletion, suspension of processing and withdrawal of consent; complaints to the Personal Information Protection Commission or the KISA privacy centre. The person responsible for personal information is the developer, reachable at [email protected].
• Australia and New Zealand (Privacy Act 1988, Privacy Act 2020): access and correction; complaints to the OAIC or the New Zealand Privacy Commissioner.
• Other countries (for example India’s DPDP Act, Singapore’s PDPA, South Africa’s POPIA or Türkiye’s KVKK): the rights your local law gives you. Write to us and we will respond in line with it.

How we respond. We answer within one month, or sooner or later where your local law sets another period (for example 45 days under the CCPA), and we may extend it where the law allows. We may ask for information to confirm that a request comes from you. Requests are free unless they are manifestly unfounded or excessive. If we cannot do what you ask, we explain why and how you can appeal or complain.

14International users

Zarvel is available in many countries. The developer does not receive the data you keep in the app, so we do not transfer it anywhere.

If you e-mail us, your message is processed by our e-mail provider and may be stored on servers outside your country. Where the GDPR or UK GDPR applies to such a transfer, it relies on an adequacy decision, on standard contractual clauses offered by the provider, or on the transfer being necessary to answer your request.

This policy is written in English. If a translation is offered, the English version prevails unless your local law requires otherwise.

15Security

Zarvel relies on Android’s application sandbox for its private data. It does not add a password-protected vault or promise encryption beyond what your device provides. The dice records carry an integrity check that detects accidental corruption; it is not a security measure against someone who controls your phone. Backup files are ordinary files.

No device or storage system is perfectly secure. Someone who can use your phone while it is open, or a compromised or rooted phone, or who has a backup file, may read it. Use a screen lock, keep your phone updated and store backups where only you can reach them.

16Ads, purchases and future versions

Today. The current version of Zarvel is free of charge, shows no ads, has no in-app purchases or subscriptions, and contains no advertising, analytics or payment SDKs. This describes the app as it is now, not a promise about future versions. Future versions may introduce advertising, paid features, in-app purchases or subscriptions, or other optional services.

If ads are introduced. Ads would be supplied by a third-party ad network, for example Google AdMob. Ad networks typically process your device’s advertising ID, IP address, approximate location derived from the IP address, device and app information and your interactions with ads, in order to show ads, limit repetition, measure performance and prevent fraud, and, only where you allow it, to personalise ads. Ads would also require the app to connect to the internet, which the current version cannot do.

If purchases or subscriptions are introduced. They would be processed by Google Play’s billing system. Google handles your payment details under the Google Privacy Policy. We would receive only what is needed to deliver and verify a purchase, such as a purchase token, the product, its status, the country and the currency, never your full card or bank details.

Before any such change we will update this policy with a new effective date and version, describing what data is processed, by whom, why and how you can control it; update the Google Play Data safety section; mention the change in the release notes; ask for your consent where the law requires it (for example for personalised ads and non-essential access to your device in the EEA, the UK and Switzerland, through a consent tool that meets Google’s requirements); and offer the opt-outs the law requires (for example under US state privacy laws). The change applies only from the app version that introduces it. Data already stored in the app will not be used for advertising without telling you first and, where required, getting your consent. We will not knowingly show personalised ads to children (§17).

17Age limits

Zarvel is a traditional board game for a general audience aged 13 and over. It is not directed to children under 13 and does not take part in Google Play’s Families programme. Its content rating comes from the IARC questionnaire answered for a board game: it has no violence, no user-to-user interaction, no purchases and no real or simulated gambling, because the doubling cube only counts match points. The rating shown on Google Play for your country applies. The app collects no personal data from anyone, of any age.

18Changes to this policy

We may update this policy when we change the app (including any change described in §16), when the services the app uses change, or when the law changes. The effective date and version at the top of this page show which version applies, and the version history (§19) summarises every change.

For a material change, for example new data leaving your device, ads or purchases, we update this page and the Google Play Data safety section before the app version with that change is published, describe it in the release notes, and ask for your consent in the app where the law requires it. Changes do not apply retroactively to data processed before them. Earlier versions are available on request from [email protected].

19Version history

20Contact

• Developer (controller): Zydeno, the developer of Zarvel on Google Play
• E-mail for privacy questions and requests: [email protected]
• Website: zydeno.com

We aim to answer within 30 days. If you are not satisfied with our answer, you can contact your local data-protection authority.

See also the Terms of Use.