Steganography. What a great word, I had to look it up after hearing it mentioned during recent news coverage of the Russia/USA spying furore.

It is apparently of Greek origin and is defined as "covered or hidden writing... a way of hiding text in plain sight". There's an interesting write-up about it on Wikipedia, containing some fascinating historical examples of the art from the days before desktop image manipulation made things so much easier - and more worryingly accessible from the point of view of the security services. Check out the picture of trees that contains a hidden image of a cat, too.

Turns out that those [supposed] Russian spies had been using steganography as part of their spying toolkit. What japes, eh? In a way, steganography is an every day feature for most of us in graphic arts, because the printers made by Xerox, Canon et al automatically include a hidden code in every printed sheet, so that the output can be traced back to their machine of origin should it become necessary due to dodgy counterfeiting type activities.

It also brings to mind something new from Océ which I heard about at a recent conference on digital book printing. Oce's "phantom code" can be placed anywhere in a page and is invisible to the naked eye. It could contain static or sequential information, and can be read using a low-cost USB pen-type reader. The firm describes it as "invisible authentication" and envisages it being used for verification purposes and also as a cross-media option for linking, for example, educational books to rich content.

It's another thing to add to the list of interesting print/digital interaction technologies, along with QR codes, Nokia Point & Find, and Clic2C.