The present invention relates to the field of tracing and anti-counterfeit protection of physical objects, and particularly to preparing and performing a secure authentication of such objects. Specifically, the invention is directed to a method and a system for preparing a subsequent secured authentication of a physical object or group of physical objects by a recipient thereof, to a method and system for authenticating a physical object or group of physical objects, to a method and system of securely providing a time-variant combination scheme for authenticating a physical object or group of physical objects according to the above methods, and to related computer programs corresponding to said methods. The invention is based on the concept of increasing the security level by increasing the information entropy of the data on which the anti-counterfeit protection is based by means of random data communicated to authenticating entities in an algorithmically hidden way.