- Printer steganography
Printer steganography is a type of
steganography produced bycolor printer s, includingHP andXerox brand colorlaser printers , where tiny yellow dots are added to each page. The dots are barely visible and contain encoded printer serial numbers, as well as date and time stamps.Color laser printers appear to be the type mostly involved, the measure being brought in during the 1990s by companies such as
Xerox seeking to reassure governments that their printers would not be used for the purposes offorgery . The identification is by means of awatermark , often using yellow-on-white, embedded in the printout of each page, and in conjunction with other information can be used to identify the printer which was used to print any document originally produced on a wide range of popular printers. It may be actual text, or a repeated pattern of dots throughout the page, more easily visible under blue light or with a magnifying glass, and is intended to be very difficult to notice with the naked eye.In 2005, the
Electronic Frontier Foundation cracked the codes for DocuColor printers and published an online guide to their detection. [Cite web | title = DocuColor Tracking Dot Decoding Guide | publisher = EFF | url = http://www.eff.org/Privacy/printers/docucolor | accessdate = 2007-12-12] Most printers' codes have not been decoded.References
ee also
*
Steganography
*Microprinting
*Coded Anti-Piracy
*EURion constellation External links
*Musgrove, Mike [http://www.washingtonpost.com/wp-dyn/content/article/2005/10/18/AR2005101801663.html "Sleuths Crack Tracking Code Discovered in Color Printers"] (October 19, 2005)
* [http://catless.ncl.ac.uk/Risks/24.08.html#subj8 Risks-L digest] (October 26, 2005)
* [http://www.eff.org/Privacy/printers/docucolor/ "DocuColor Tracking Dot Decoding Guide"] Electronic Frontier Foundation (October, 2005)
* [http://www.eff.org/Privacy/printers/ Electronic Frontier Foundation information pages]
* [http://www.pcworld.com/news/article/0,aid,118664,00.asp pcworld article 2004]
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