1. Who we are
Sudoku: Challenge a Friend (the "App") is published by Rocket Game Station ("we", "us"). This policy explains what information the App handles, why, and what control you have over it.
The App has no user accounts. You do not register, and you never give us an email address, phone number, or password to play.
2. What we collect
2.1 A randomly generated player ID
When you first open the App, it generates a random 16-byte identifier using your device's secure random number generator. This ID is not derived from your hardware — it is not your device's serial number, IMEI, MAC address, Android ID, or advertising ID. It exists so your leaderboard entries and challenge results can be recognised as yours.
The ID is stored on your device. If you clear the App's data or uninstall the App, it is destroyed, and a new unrelated ID is generated the next time you play.
2.2 A display name, if you choose to enter one
You may set a display name to appear on leaderboards and in challenges. This is optional and entirely up to you. Please do not use your full legal name or any other information you would not want shown publicly — the name is visible to other players.
2.3 Gameplay data
When you submit a score to a leaderboard, complete a daily challenge, or play an online challenge, the following is sent to our database:
| Data | Purpose |
|---|---|
| Difficulty level | Ranking within the correct leaderboard |
| Completion time | Ranking |
| Number of mistakes | Ranking and tie-breaking |
| Timestamp | Ordering daily and tournament results |
| Player ID and display name | Attributing the result to you |
2.4 Data kept only on your device
Your settings, themes, statistics, streaks, achievements and puzzle progress are stored locally on your device. This information is not transmitted to us unless it forms part of a score you submit or a challenge you join.
2.5 Advertising data
The App shows advertisements supplied by Google AdMob. To serve and measure ads, Google may process your device's advertising identifier, IP address, general device information, and interaction with the ads shown. We do not receive this data ourselves; it is handled by Google under its own policies. Where required, the App asks for your consent before personalised ads are used, and you can change that choice at any time in the App's settings.
3. What we do not collect
To be explicit, the App does not collect any of the following:
- Your name, email address, phone number, or postal address
- Location or GPS data
- Contacts, photos, camera, microphone, or files
- Health, financial, or payment information
- Behavioural analytics — the App contains no analytics SDK
- Crash or diagnostic reports — the App contains no crash reporting SDK
The App does not send push notifications and does not request permission to do so.
4. How we use it
- To run leaderboards, daily challenges, and tournaments
- To let you challenge another player and show each other's live progress during a match
- To keep your progress, achievements and streaks working across sessions
- To display advertisements, which fund the App's free distribution
We do not sell your data, and we do not share it with anyone other than the service providers named in section 6.
5. Legal basis for processing (EEA and UK users)
| Processing | Legal basis |
|---|---|
| Leaderboards, challenges, gameplay features | Our legitimate interest in providing the game feature you asked for |
| Personalised advertising | Your consent, requested in the App and withdrawable at any time |
| Non-personalised advertising | Our legitimate interest in funding a free App |
6. Third-party services
| Service | Provider | Role |
|---|---|---|
| Firebase Realtime Database | Stores leaderboard entries and online challenge sessions | |
| AdMob | Serves banner, interstitial and rewarded advertisements | |
| Google Play services | App distribution, updates, and in-app review prompt |
Google's handling of this data is governed by the Google Privacy Policy. You can manage or reset your advertising identifier in your device settings.
7. Retention and deletion
On your device. Everything stored locally is removed when you clear the App's data or uninstall it. You control this entirely and need not contact us.
On our servers. Leaderboard entries and challenge results are kept while the leaderboard they belong to is active. Daily and tournament boards roll over on their own schedule.
Deletion requests. To have your submitted entries removed, email us at rocketgamestation.dev@gmail.com from any address and include your display name. We will delete the matching entries within 30 days. Because we hold no account and no contact details, your display name is the only way we can find your data.
8. Children's privacy
The App is a puzzle game with no objectionable content, but it is not directed at children under 13, and we do not knowingly collect personal information from them. If you believe a child has provided us with personal information — for example by entering their real name as a display name — contact us and we will remove it.
9. Your rights
Depending on where you live, you may have the right to access, correct, delete, or restrict the processing of your personal data, to object to processing, to data portability, and to withdraw consent at any time. In practice, for this App:
- Access and portability — email us with your display name and we will send you the entries we hold
- Deletion — clear the App's data for anything local; email us for server-side entries
- Withdraw ad consent — change your choice in the App's settings at any time
- Complain — you may lodge a complaint with your local data protection authority
We do not sell or share personal information as those terms are defined under California law.
10. Security
Data in transit between the App and our database is encrypted using TLS. Our database is operated by Google Cloud with access restricted to us. No system is perfectly secure, but the App is designed to hold as little about you as possible — which is the strongest protection we can offer.
11. International transfers
Our database and advertising provider are operated by Google and your data may be processed on servers outside your country, including in the United States. Google provides appropriate safeguards for such transfers, including the European Commission's Standard Contractual Clauses.
12. Changes to this policy, and how to contact us
If we change this policy we will update the date at the top of this page and, where the change is significant, notify you inside the App. Continuing to use the App after a change means you accept the updated policy.
Questions, requests, or complaints:
Rocket Game Station
rocketgamestation.dev@gmail.com