| 摘要 |
PURPOSE:To prevent the duplication, the forgery and the alteration of the same document by assembling beforehand electric conductive substance in the document at random, and applying an electric wave, and measuring the reflected or the transmitted electric wave, and using the measured and numeralized signal as a random numbers train. CONSTITUTION:The conductive substance to give effect upon the electric wave like a milimeter wave and a microwave is mixed beforehand in the sheet-shaped document of the paper or the PET, etc., of nonconductive substance, and it is irradated by the electric wave like the milimeter wave or the microwave. Then, reflection or transmission from it is measured, and the measured signal is converted into a numerical value, and by grasping it as the train of the random numbers, the random numbers peculiar to every one sheet of the document are obtained. The peculiar random numbers read by the microwave are used as a key word, and information to be entered in the document originally is written based on the key word after converting them by the method of a conversion table or others. Thus, the forgery and the alteration of the document can be made difficult. |
