Privacy — Cryptarithm

Analytics and cookie choices

Ahrefs Web Analytics loads on the public site to measure visits, pages, referrals, language, device information, and link interactions. Ahrefs states that its default analytics does not use cookies. These requests send usage and connection information to Ahrefs.

For visitors in the European Economic Area, the United Kingdom, or Switzerland, Google Analytics 4 waits for permission. Elsewhere it loads by default unless you have declined. Cloudflare identifies the country from your IP address, not your interface language; the region endpoint returns only whether consent is required, not your IP or country. If detection fails, we ask for permission before loading Google Analytics.

When active, Google Analytics 4 uses cookies to measure visits and returning visitors; advertising storage, advertising personalization, and Google signals are disabled. Declining does not prevent you from playing. We do not send your saved answers or notes to either analytics service.

When Google Analytics is enabled, we also measure puzzle starts and completions, displayed completion time and check count, changes of puzzle type, operation or difficulty, editing-tool use, share, copy and image-download actions, and print requests (which game, one puzzle or a worksheet, and how many puzzles). Events include the puzzle category and interface language, not entered digits, notes or puzzle IDs. On the solver page, we measure the chosen operation, the number of words and different letters, the result type and number of answers, whether you open the answer, and how far you follow the animated walkthrough, but never the words you type. In All Ten, we measure when you start and finish a puzzle, your time, when you open its leaderboard, and how you share a result, but never the numbers or expressions. In Kakuro, we measure when you start and finish a puzzle, the grid size, and your time, but never the grid or the digits you enter. In Calcudoku, we measure when you start and finish a puzzle, the grid size, the level, the operations used, and your time, but never the grid or the digits you enter. We also measure when you open either game’s leaderboard and which game you switch to from the game list, menu, or footer. Gameplay events are not sent to Ahrefs. Actions while Google Analytics is disabled are not saved for later reporting.

Your Google Analytics choice is stored for up to 180 days in localStorage under cryptarithm.analytics-consent.v1. Use Cookie settings in the footer to change your choice. Declining stops Google Analytics collection and removes its cookies on this site without clearing game progress; it does not remove data already received by the providers. Ahrefs cookie-free analytics remains active independently of this Google Analytics choice. Provider privacy policies are linked below. Automatic loading outside these regions is not saved as an explicit consent choice.

Data kept in your browser

The application stores puzzle history, entries, notes, timing, completion statistics, language preferences, and the sound setting in localStorage under cryptarithm.save.v1. Clearing site data removes this local copy.

Refreshing the page continues the current puzzle with its entries, notes and time; opening a link to a different puzzle starts that puzzle afresh. Kakuro, Calcudoku and All Ten practice keep only the puzzle in progress (the grid or the four numbers, your entries or expressions, and the time) under cryptarithm.kakuro.game.v1, cryptarithm.calcudoku.game.v1 and cryptarithm.allten.practice.v1. This progress stays in this browser and is replaced when you start another puzzle.

What leaves the browser

Puzzle generation and ID restoration require a connection to our server. When you use Check or fill all cells, the puzzle ID and your entered digits are sent to the server for validation. The application does not store those entries on the server. QR and PNG creation stay on your device. A shared URL contains the puzzle ID, not your answers, notes, or elapsed time.

Your browser still requests pages, fonts, images, and sound files from the website host. The hosting provider may process connection information such as IP addresses and request logs under its own policies.

Downloads and external links

Downloaded images are saved on your device. Clipboard actions happen only when you request them. Following an external link takes you to a service with its own privacy practices. The Share to Classroom button only opens Google Classroom’s share page in a new window with a link to this site; we send no data to Google, and Google’s own privacy practices apply from there.

We update this page when our data-handling practices change. For privacy questions, email feedback@cryptarithm.com.

Daily challenge privacy

One ranked attempt per browser identity each UTC day. Your player number, progress and score are public. Rankings compare floors first, then time.

An anonymous identity cookie lasts one year. Server records are kept for one year; entries and notes stay on this device. Clearing cookies or switching devices loses access. This casual leaderboard cannot prevent outside help or new identities. When you start a challenge, Cloudflare estimates your country from your IP address; we store only the country with that day’s result and show it as a flag on the public leaderboard. We do not store your IP address.

The All Ten Daily Challenge uses the same anonymous identity. Our server keeps your start time, the expressions you made, and your finishing time for one year, and finishers’ player numbers and times appear on its public leaderboard.