Originally, QR codes were used to mark assemblies and components in the car manufacturing sector. Nowadays, QR codes are also used for invoices (QR invoices) as well as in the publishing and marketing sectors to link physical objects (products, print media, posters, etc.) with the online world and make additional information available this way. As the contents of QR codes cannot readily be decoded by humans, these codes have to be scanned in first, e. g. using a smartphone.
Users cannot usually see what kind of information is coded into them before scanning in a QR code. If possible, they should therefore use a QR code scanner (app) which displays the decoded contents first and asks them whether they would actually like to visit a link or execute a certain action.
Example QR code by “eBanking – but secure!”