A bit off-topic, but >By special request from the police (mainly the FBI but probably equally >popular with cops from Afghanistan to Zimbabwe) these things also have >steganographic encoding of the copier identity in every image they make. > >Remember when we used to snigger at the Soviets for registering samples >of typewriter output?
>From a technical point of view, encoding steg info in a picture in such a way that it will survive the printing process and be recoverable from a scan of the page is very difficult. I doubt it could be done in such a way as to keep the watermark invisible. If it can be done I'd like to know the technical details (so's I can figure out a way to subvert it:-) Phil Taylor To subscribe/unsubscribe, point your browser to: http://www.tullochgorm.com/lists.html
