The Null Device

Those rumours about colour laser printers putting hidden tracking codes in their output, at the behest of the Men In Black the government are true; a team of hackers led by the EFF have cracked the code used by Xerox printers, and are working on other manufacturers' codes:

The DocuColor series prints a rectangular grid of 15 by 8 miniscule yellow dots on every color page. The same grid is printed repeatedly over the entire page, but the repetitions of the grid are offset slightly from one another so that each grid is separated from the others. The grid is printed parallel to the edges of the page, and the offset of the grid from the edges of the page seems to vary. These dots encode up to 14 7-bit bytes of tracking information, plus row and column parity for error correction. Typically, about four of these bytes were unused (depending on printer model), giving 10 bytes of useful data. Below, we explain how to extract serial number, date, and time from these dots. Following the explanation, we implement the decoding process in an interactive computer program.

(via bOING bOING) ¶ printers surveillance tech xerox 0

This is nifty: Random Movement Printing Technology. A printer the size of a mobile phone, which you can download images/data to, and then use it to print on any piece of paper (or other printable surface) by rubbing the printer over it. The printer tracks its movement and rotation and prints the appropriate parts of the image as it moves.

I'm now thinking that if someone were to fit these with indelible paint nozzles, they could use them as an urban graffiti tool, sort of like a more high-tech analogue of stencil art. The street finds its own uses for things and all that.

¶ graffiti printers tech 1