QR codes are those pixelated-looking black-and-white squares that you can scan with your phone for more information about something, whether it’s an advertisement or a piece of art. They’ve become ubiquitous, especially after the COVID-19 pandemic popularized contactless menus and payment. However, they’re very rarely called by their full name.

“QR” actually stands for “quick response,” and the codes can be used to share far more than a link. If you wanted to, you could share an entire book with one code. The technology was first developed by a Toyota subsidiary in the mid-’90s as a way to track auto parts, but QR codes found new life as a way to direct smartphone users from a physical space to a digital one. They used to require a special reader, but nowadays, most smartphone camera apps will read QR codes on their own.

Don’t be so quick to scan a QR code. There is a warning that comes with using QR codes.  A malicious QR code may lead you to a spoofed website designed to drop different malware types or steal your sensitive data, like your login credentials, credit card information, or money. In one incident, cybercriminals were using fake parking meter QR codes to steal money through phishing websites.