A method of identifying an object having identification information, said identification information being used to verify the object's identity, said method comprising: determining at least one characteristic of a magnetic field of at least a portion of a tag, thereby obtaining a first specific magnetic signal, wherein the tag comprises a substantially non-magnetic host material having pores, wherein at least some of the pores contain a magnetic material, and storing signal information relating to said first specific magnetic signal, said stored signal information forming the identification information of the object.