What is a machine-readable code used in retail to identify unique items?

A barcode is a machine-readable code used in retail to identify unique items. It consists of a series of parallel lines and spaces that encode data, typically in the form of numbers, representing the product's information. Scanners read these codes quickly and accurately, allowing for efficient pricing, inventory management, and checkout processes in retail environments.

Barcodes, commonly found on nearly all retail products, enhance the speed and accuracy of transactions by allowing scanners to quickly retrieve product information and pricing from a database, thus streamlining operations. They have become a standard in the industry, enabling retailers to manage inventory and track products effectively.

While QR codes and RFID tags are also machine-readable technologies used for various purposes, they serve different functions. QR codes can store more information and can be scanned by smartphones, while RFID tags use radio waves to communicate with a reader but are primarily used for tracking products in a supply chain rather than direct retail transactions. Digital signatures do not apply to product identification in the retail context as they are used to ensure the authenticity and integrity of digital messages or documents.