Among the many changes brought about by the pandemic is the widespread use of QR codes, graphical representations of digital data that can be printed and later scanned by a smartphone or other device.

The QR code is having an extended moment, given that we’re all still wary of dealing with physical documents, touching surfaces, and generally interacting with the world at large. The switch to ...

QR codes are pixelated black and white squares that perform magic when we point the cameras on our phones at them—but what’s going on that makes this little spell possible? QR codes are akin to the ...