QR codes have been around for the last 25 years. Masahiro Hana, a Japanese engineer, developed QR code in 1994. He was inspired by a board game Go where black and white stones are placed alternately in a grid pattern. The grid can represent a lot of information.
The forerunner of QR code was a barcode which conveyed a variety of information on being scanned. A QR code holds information in both horizontal and vertical dimensions. Thus it can hold more information than a barcode. A QR code can store up to 7089 digits or 4296 charaoters. These have links to webpages, PDFs, text and images. QR codes are scanned by smart phones.
QR codes are used in travel and tourism, healthcare, restaurants, FMCG sector, entertainment, textiles, education and publishing, banking, e-commerce, and charity. You must have seen the ubiquitous QR codes for making UPI payments on the premises of retail shopkeepers.
QR codes must be made more secure so that these do not introduce any malware on our phones.