Machine-readable codes, also commonly known as barcodes, are identification codes that, as the name suggests, are designed to be readable by technologies such as optical scanning devices.

A barcode consists of a series of parallel black lines and white spaces or of dots and squares (or a combination of the two), of varying widths. Written into the codes are unique identifiers or product-related data, such as the date and place of manufacture, owner, origin, expiry date, etc. 

The data contained in the codes are analysed and extracted by a reader – current devices include a laser beam or a smartphone camera – which decodes the binary information in the barcode. 

Some optical security features may be ‘bound’ to machine-readable codes in order to automate the smartphone identification and authentication process. Alternatively, machine-readable codes may be embedded into other visual security features, which, when scanned, can provide additional verification instructions or product information and enable traceability.