Patent ID: 7792291

Claim:
An article of manufacture for secure message delivery, the article comprising: a transparent base layer with a first side and a second side; first encoding layer bonded to the first side of the transparent base layer; and a second encoding layer bonded to the second side of the transparent base layer in a location opposite the first encoding layer; wherein the transparent base layer and its bonded first and second encoding layers define an XOR message area in which: (a) the first encoding layer encodes a first message visible only from the second side of the transparent base layer and the second encoding layer encodes a second message visible only from the first side of the transparent base layer; (b) when the first encoding layer is removed from the transparent base layer, the first encoded message is rendered illegible and the second encoded message is revealed; and (c) when the second encoding layer is removed from the transparent base layer, the second encoded message is rendered illegible and the first encoded message is revealed.