Quick Codes Go Undercover

Quick response (QR) codes are becoming ubiquitous. When read by a cellphone, these small squares of black square dots provide additional details on a product, service or activity. Now, a team of scientists from two South Dakota universities has developed an ink from unique nanoparticles to print covert QR codes.

Counterfeiting costs government and private industries billions of dollars annually. With the covert QR codes, organizations can embed secret information. This data can help prevent counterfeiting of products like currency and pharmaceuticals.

Researchers from the University of South Dakota and the South Dakota School of Mines and Technology created the inks that can be printed in a variety of patterns including micron-sized letters, stencil patterns and QR codes. They have printed the patterns on a variety of surfaces including paper, glass and adhesive tape. The printed patterns are invisible to the naked eye, however, when a laser shines on the pattern it glows with an intense green color. The inks can also covertly display other colors. To recover the secret embedded information, users scan the QR code with a smartphone.