A packaging film which contains pigment particles randomly distributed in a low surface-area density is used for the authentication of products. An imaging device is used to record a first digital image of a packaged product. The positional coordinates, and optionally the color values, of the pigment particles contained in the packaging film are determined from the digital image by means of a computer program and an identification code is calculated from the coordinate or color values and stored in a database. To authenticate the product at a later time, a second digital image is recorded and a test code is determined and compared with the recorded identification code.