Somehow, I think some of the readers of this list will find this interesting, I don't know why. Popular Science: April 1993 "Color Copiers Countering Counterfeiters An unfortunate result of advances in color copiers is that it is now easier to counterfeit currency. To make it more difficult, Cannon has developed two defenses. One is a currency-recognition technology similar to that used in vending machines. But Canon has enhanced the technology to recognize a bill regardless of its orientation of it it's among a clutter of material. In a demonstration, a Canon official tried to copy a Japanese bill. The copier sounded an alarm and spit out a piece of paper with a blackened rectangle where the image should have been. "Once a bill is recognized, we could do anything -- have the machine stop, sound an alarm, or, it it's connected to a phone line, call the police,' the official says. The copier will recognize as many currencies as possible. A second feature traces counterfeiters of official documents. Each copier embeds a code into the copied image, which is impossible to see. A special scanner extracts the code and a computer program then furnishes the copier's serial number, allowing identification of the registered purchaser of the machine. With the new anti-counterfeiting technology, Canon can also include a two-sided copying feature previously omitted from its color copiers." Of course, the second to the last paragraph is most interesting, along these lines: a. how are they doing that? b. is this preserved on a second, third, etc. generation copy? c. it is likely that computer scanning and OCR defeats this. c. anybody posting to whistleblowers should be aware of these new machines, and learn how to identify them, and their products. -a2.