In a system for authenticating information, a holographic element,
including a first layer of optical information in a first coded pattern
and a second layer of optical information in a second coded pattern is
inserted into a reader. The reader includes an opening into which the
holographic element may be positioned, a light source, a first detector
positioned at a first predetermined distance from the location of the
holographic element when the holographic element is positioned in the
opening, and a second detector positioned at a second predetermined
distance from the location of the holographic element when the
holographic element is positioned in the opening.