Logic Mastermind
Privacy Policy
Effective 14 September 2026
Logic Mastermind is an Android puzzle app published by Mateusz Ciosek ("we", "us"), who is responsible for the data described here. This policy says what the app collects, who sees it, how long it is kept and how to have it deleted. The whole thing takes about five minutes to read.
The short version
- Every installation gets an anonymous account with Google Firebase. You do not give an email address to play. You can link a Google account to carry the paper to another phone; that is optional.
- Some things are printed for other readers: your byline (a random one unless you choose your own), your friend code, your streak, your daily solve times with hints and mistakes, and your rating and match results. Nothing else about you is shown to anyone.
- We collect usage statistics and crash reports through Firebase to see which puzzles and hints work and to fix crashes.
- The free paper carries advertisements from Google AdMob. They are chosen for you only if you say so, and where the law requires it, Google asks for your consent first. The subscriber's edition removes them.
- The subscriber's edition is one purchase through Google Play. We receive the date of the purchase and nothing about your payment.
- We sell nothing. You can close your account in the app at any time, or ask us by email.
What stays on your phone
The puzzles you have started, your settings (sound, notices, the paper's ink), your answer about advertising, and the pictures of a board you choose to share. Your progress is also kept on the phone so the paper works offline. Android may include the app's on-device data in your phone's own backup to your Google account; that backup is controlled by your Google settings and we cannot read it.
Notices ("Extra!") are off until you turn them on. They are scheduled on the phone; nothing is pushed to you from a server.
Your account and what it holds
On first start the app signs you in anonymously with Firebase Authentication, which gives the installation a random account number. Everything below is filed under that number, in Google Cloud (Firestore in Frankfurt, the Realtime Database and our server functions in Belgium).
| What | Why | Who can see it |
|---|---|---|
| Byline (the name printed for you, 2 to 24 characters; random until you change it), friend code, streak, the day you last solved, how many honours you hold | So the results page, friends and the fixtures page can name you | Other readers of the app. Please do not use your real name as a byline unless you want it printed. |
| Daily results: solve time, hints, mistakes, the paper and difficulty, app version | To rank the day fairly on the results page | Other readers |
| Rating and match records: races, the cup, live games at the table (seats, moves, presence while you are at the table) | To run matches between readers and keep the ladder | Other readers |
| Your shelf: puzzle progress, statistics, hints used today, honours, the date you bought the subscriber's edition | So your paper follows you to another phone and a reinstall | Only you |
| Your friends list (their bylines and codes) | To print your friends' times beside yours | Only you |
| Google account email, only if you link a Google account | To sign you in on another phone | Held by Firebase Authentication. The app shows it to you in the colophon and stores it nowhere else. |
The app does not read your Google profile name or photo, contacts, location, photos, files, microphone, camera or clipboard.
Statistics, crash reports and security
The app uses these services from Google LLC:
| Service | What it receives | Why |
|---|---|---|
| Firebase Analytics | Which pages you turn to and what you do in the app (a puzzle started, a hint asked, a puzzle solved, with its paper, size, difficulty and technique); device model, Android version, app version, language and country (derived by Google from the IP address); an installation identifier and your account number. Not your byline, email or advertising ID. | To learn which puzzles are too hard, whether hints help and whether readers come back |
| Firebase Crashlytics | Crash reports: the stack trace, device model, Android version, memory and storage, app version, the app events just before the crash, and your account number | To find and fix crashes |
| Firebase App Check and Play Integrity | A signal that the request comes from a genuine copy of the app on a genuine device | To keep the results fair and the service safe from abuse |
| Firebase Remote Config | An installation identifier | To switch a section of the paper on or off without an update |
Google keeps user-level Analytics data for two months and Crashlytics reports for 90 days.
Advertising
The free paper prints advertisements in labelled boxes and a full-page supplement before a puzzle opens (at most once a day before a daily puzzle, and before every third practice puzzle). They are served by Google AdMob. Nothing is requested from AdMob before you have answered the paper's own question, "A word about advertising", and, where the law requires it, Google's consent form.
- "Chosen for me": AdMob may use your phone's advertising ID to choose advertisements for you, subject to the consent you give in Google's form.
- "The same for everyone": the app asks for non-personalised advertisements. AdMob still receives the advertising ID, IP address, device information and which advertisements were shown and tapped, but uses them only for limited purposes such as counting, frequency capping and fraud prevention.
You can change either answer in the colophon. You can also reset or delete your advertising ID in Android's settings. How Google uses this data is described at policies.google.com/technologies/partner-sites. The subscriber's edition prints no advertisements and asks nothing.
Purchases
The subscriber's edition is a single in-app purchase through Google Play. Google handles the payment under its own terms and privacy policy. We receive the confirmation that the purchase was made and its date, which is kept on your shelf so the edition follows you to another phone. We never see your card or payment details.
Sharing
We do not sell your data or share it for anyone else's marketing. Data reaches others only as described above: other readers see what is printed for them, and Google processes data for us as our service provider and, for advertising, under its own responsibility. A picture of a board or your friend code leaves the app only when you share it yourself through Android's share sheet.
Google may process data outside the European Economic Area. Such transfers are covered by the European Commission's Standard Contractual Clauses and the EU–US Data Privacy Framework.
Why we may use it
- To provide the paper you asked for (your account, results, friends, matches, syncing, the purchase): performance of our agreement with you.
- Statistics, crash reports, security and non-personalised advertising: our legitimate interest in keeping the app working, fair and free to read. You can object by email.
- Personalised advertising: your consent, which you can withdraw in the colophon at any time.
How long it is kept
- Your account, shelf, results and friends: until you close the account. An account that was never linked to Google cannot be reached again once the app is uninstalled; it stays dormant until you ask us to delete it.
- Live games at the table: removed a day after the game ends, or two days after it was laid if it never finished. Listings in the lobby: removed after an hour.
- Analytics: two months at user level. Crash reports: 90 days.
Closing your account and deleting data
In the app: Colophon › Your account › Close this account. This deletes your account, shelf, byline, friend code, results, rating, friends list and table seats, and removes you from other readers' friends lists. A race or cup tie is also another reader's record, so its result stays, with your byline replaced by "a former reader"; the random account number it was filed under no longer belongs to any account. Everything on the phone is wiped except its settings.
If you can no longer open the app, or you also want your Analytics and crash data deleted, see how to ask for deletion.
Your rights
You have the right to access, correct, delete and receive a copy of your data, to restrict or object to its use, and to withdraw consent at any time. Write to us at the address below; we answer within one month. You can also complain to the data protection authority where you live (in Poland, the Prezes Urzędu Ochrony Danych Osobowych).
Children
The app is meant for readers aged 13 and over. It is not directed at children under 13 and we do not knowingly collect data from them. If you believe a child under 13 has an account, write to us and we will delete it.
In some countries a reader needs to be older to agree to personalised advertising on their own (16 in Poland and Germany, for example). A reader below that age should answer "The same for everyone", or ask a parent to decide.
Changes
When this policy changes, the effective date at the top changes. Material changes are also mentioned in the app's release notes before they take effect.
Contact
Mateusz Ciosek
mateusz.ciosek@hotmail.com