How does it happen that we can create millions of QR-Codes daily and they are still unic?
In: Technology
The QR code is just a URL encoded in little squares. Uniqueness is just an effect of the URL naming convention.
The largest QR code can have something like 10^4515 unique positions. It’s estimated there’s 10^82 atoms in the universe. We would run out of storage space before we run out of unique QR codes.
Same way that it happens we can create millions of text messages every day and they are still unique.
A QR code is just a way of writing stuff down that machines can read easily.
The patterns are actually more like a series of letters in a text, plus a little extra that tells the machine how to read it.
The ELI5: [by expanding them, theoretically, infinitely (the current version maxes out at a little over 1800 characters).](https://upload.wikimedia.org/wikipedia/commons/thumb/d/dd/Qr-code-ver-40.svg/1024px-Qr-code-ver-40.svg.png) Though a new and better standard will likely come out long before every day QR codes reach that size.
How this works is a bit more advanced but not too crazy to understand the basics. There are a few different components of a QR code that are standardized:
* The positioning cubes. Three cubes in the upper left, upper right, and lower left corner that tell the processor where the QR code begins and ends.
* Formatting info that immediately surrounds said positioning cubes. Getting a tad more in depth, this tells the processor how to decode the message and is what allows for a majority of the uniqueness as two equal patterns with different formatting would result in a different decoded message.
* Alignment and timing. These are the smaller cubes you see and while it isn’t as visible, you’ll typically see a standard dotted line bisecting said cubes that help further align the code.
From there, the data that isn’t standardized consists of some additional encoding and masking info and then the actual data itself stored in 8-bit cells where each black or white pixel represents a 0 or a 1.
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