Typing your phone number into a website you have never heard of is a reasonable thing to feel unsure about. We would feel the same. So instead of just saying "trust us", this note walks through what happens to your number, step by step, and shows you how to check some of it yourself.
The short version: your number is looked up and forgotten. There is nowhere on this site where it could be kept.
Why we don't need to keep it
Most websites that ask for a number need to remember it, because they want to send you something or recognise you next time. We don't do either. There are no accounts here, no sign-up and no email box.
The search itself doesn't need your number for more than a moment either. Long before you arrived, we made a giant table that says where every ten-digit number first appears in the first 100 billion digits of π. Your number is just used to pick the right line in that table, like using a page number to open a book. Once the line has been read, the number has done its job. The full story of that table is in how we search the digits.
The journey of one search
Here is what happens between pressing the button and seeing your answer.
- Your number leaves your browser inside the request. It is not put in the web address. That matters, because web addresses get saved in browser histories, bookmarks and server records, and the inside of a request does not.
- Our server reads one line of the table. That gives the place in π where your number first appears.
- Our server reads the digits around that place from our own copy of π's digits, so we can show you your number sitting among its neighbours. No other company is asked for them.
- The answer is sent back to you, and the server lets go of everything. Your number and its place are not written to a database, a record of requests or a statistics tool.
The place is a secret too
There is a catch that is easy to miss. If we stored only where your number was found, that would be nearly as bad as storing the number. Anyone who knows the place can go and read the digits there.
So we treat the place exactly like the number: never stored, never written down, never put in a web address. It is why the Hall of Finds only takes everyday dictionary words that people choose to hang there, and only says roughly how deep each one hides.
What we do record
It would not be honest to say we record nothing at all, so here is the whole list.
- A line per request. Like every website, the service that hosts us notes the time, your IP address, your browser type and which door was knocked on (for example "search"), never what was searched. These lines are deleted after 30 days.
- A scrambled counter. To stop one connection searching thousands of times a minute, the server keeps a scrambled version of your IP address in its memory for a few minutes. It is never saved.
- A robot check. The first time you search, Google's reCAPTCHA checks that you are a person and not a program. Google sees your browser, not your number.
- Game streaks. If you play the daily games, your browser makes up a random code so your streak can be remembered. It isn't linked to your name or to anything you searched.
The privacy notice says all of this in full.
Check it yourself
You don't have to take our word for the parts that happen in your own browser.
- Watch the address bar. Search for something and look at the top of your browser. The address doesn't change, and your number is not in it.
- Start with a made-up number. Try 1234567890, or today's date, and see how the site behaves before you type anything of your own.
- Peek at the request. If you know your way around your browser's developer tools, open the Network tab and search. You will see one request to our server with your number inside it, and none carrying it to anyone else.
- Look for a login. There isn't one. A site that never asks who you are cannot tie a number to you.
The part you cannot see is what our server does after it answers. For that, this note and the privacy notice are our promise in writing.
And if you would still rather not
That is completely fine. Search for your birthday, a word, or your name on a phone keypad instead. You can also dial a place in π and see which digit lives there, or play a Name Fight. Your phone number will still be hiding in π whenever you feel like looking.
Sources
- MDN: the POST request method, on sending data inside a request instead of in the address.
- OWASP: Information exposure through query strings in URL, on why private values don't belong in web addresses.
- Google Cloud: Calculating 100 trillion digits of pi on Google Cloud, where our copy of the digits comes from.