A matrix barcode stores data in a two-dimensional grid of contrasting modules, usually black and white. QR codes are a common example. A scanner interprets the grid and converts it into information such as a web address or contact details; the visible pattern itself does not reveal whether that information is trustworthy.
In cyber security, this distinction matters because a barcode can encode a link that leads to a phishing page or other unwanted destination. Attackers may place misleading codes where people expect legitimate ones, while defenders can inspect the decoded content before opening it. Use a scanner that previews the destination, check that address carefully, and avoid treating a familiar-looking barcode as proof that its payload is safe.