Infrared steganography with individual screening shapes applied to postage stamps with security features

摘要

Designing a postage stamp requires positioning of graphic security elements in a limited small format, so the design is made for two states: for the visible spectrum and the infrared spectrum. Individual screening elements are introduced as security elements in the steganography of invisible pictures in the 700 to 1000 nm spectrum. The CMYKIR theory of hiding the infrared message in the picture is extended by mixing process inks with the control of spot twins of the same colour tone in the X0 and X40 states. Two pictures are integrated in the security print; a multicolour picture visible to the naked eye, and another hidden picture visible when illuminated with an IR detecting instrument. The CMYKIR method is joined with the new element’s algorithm used for dispersing of the hidden picture’s ("Z picture’s") fringes. This kind of steganography is applied in the design of postage stamps and it is a new way of securing them.