The invention relates to a method for producing a security paper or board product carrying micro or nano structures such as diffractive optical elements in which method the diffractive structures are integrated into the security paper or board product at the manufacturing process of said product. The invention also relates to a method for producing a security package carrying diffractive structures in which method the diffractive structures are integrated into the security package at a manufacturing stage of the security package material. The invention further relates to a security package containing authentication information in a form of diffractive structures in which package the diffractive structures are included in the security package at least in one of the following forms: as embossed in the package material, as part of the size or paste or resin used in the manufacturing process of the security package, or as part of the ink used in printing the security package or the security package material. |