As their name suggests, marking technologies work by marking products with unique security features, mostly graphic patterns or codes.

The main purpose is to authenticate rather than identify individual products. The security they provide against reproduction and tampering comes either from the nature of the technology itself (e.g. the chemical and physical characteristics of an ink) or the information it contains (e.g. in a graphic pattern). In the first case, security is provided by a visual indication of attempted alteration while, in the second, security comes from the difficulty of cloning or reproducing the information.

In some cases – where a unique code (e.g. a barcode) makes up part or all of a marking technology (or can be incorporated into it) – they can also support product traceability by making it possible to register products as they move along the supply chain.

There are several different types of marking technologies. The most widely used are those that can be inspected visually on account of their variety, low cost per item and simple verification procedures – in many cases, verification can be performed by a visual inspection or via a smartphone.