QR

I recently discovered that the search engine DuckDuckGo generates a QR code for a query that begins with “qr” (it has been doing this since 2013).

By the way, in addition to the plain text in the QR code can be written:

• Wi-Fi network data, including password (look for QR code on your modem): WIFI:T:WPA;S:mynetwork;P:mypass;,
• geolocation: geo:40.71872,-73.98905,100,
• events (name, start and end dates and times)
• malicious link,
• as well as many other things.

More information is collected here: https://github.com/zxing/zxing/wiki/Barcode-Contents

There are several QR code libraries for the Go programming language, and I used this one: https://github.com/liyue201/goqr