EFF cracks the tracking code in Xerox printers
The Electronic Frontier Foundation has decoded the secret tracking dots that are automatically printed onto color documents by new Xerox color laser printers. The technology works by printing an 8×15 grid of nearly invisible yellow dots on every single page. These dots reveal the time and date of when the page was printed as well as the printer’s serial number. It even includes a row and column of parity data that allows correction of a single dot read error and validates a successful read. Somewhere in the NSA or FBI they probably have modified scanners designed just to read these dots at high speed, thus vacuuming up tracking data from whole stacks of papers in short order.
The big question, though, is how the serial number is implemented. Does Xerox keep a database of these tracking numbers and cross-reference them with the shipping addresses that the printers were sent to? This would allow active forensics, i.e. the FBI analyzes a printed ransom note, looks up the code in Xerox’s database, and finds the identity of the kidnapper. Or is the serial number not tracked by Xerox? This would only allow passive forensics, e.g. the FBI has found a credible suspect in a kidnapping through other means, confiscates his printer, reads its serial number, and determines that it was the same printer that was used to print the ransom note.
The main application of this technology seems to be taking down currency counterfeiters. The dots are printed in small grids that are repeated across the page, so even when the page is cut up into dollar bill-sized pieces, it’s likely an entire tracking grid would still be intact. Of course, this is only speculative; there’s no way to know if the government didn’t have more sinister purposes in requesting this feature. Also, does anyone else find it unethical that Xerox started inserting this into their printers without informing customers? They’re required to accurately represent all of the specifications of their products, so how could this not be mentionable? The vast majority of Xerox printer buyers aren’t counterfeiters and probably don’t appreciate being considered potential criminals, so why should they have to put up with all sorts of tracking data on all of their documents? If I print a piece of paper and hand it to someone else, I don’t want them to be able to recover information like my printer’s serial number!
