Security Foils

Holograms (Both in true colour or standard holographic reflection.)
 

Hidden Imagery(ie Nano text and Micro text.)

Scrambled Indicia
 

There are many forms of added security  available in Hot Stamping Foil. 

Perhaps the most recent is the "Scrambled induce". This is basically hidden text within a holographic background that only becomes visible when viewed through a  decoder. In the picture above the decoder is a plastic lense that is placed above the foil. The word secure is then visible.

This is for product authentication and is extremely difficult to copy.