Printing Keys and using OCR.

[Robert J. Hansen]

> Know of a system that can take binary data and output an image to be
> printed out, that is then capable of extracting that binary data from
> an imperfect scan of the image.

QR coding is pretty nice.  3kb of binary storage per bitmap, and it's  
an international standard: ISO/IEC 18004.  There may be an open- 
source implementation of it already.  If there's not, you could do  
the community a favor by writing one.  :)

http://en.wikipedia.org/wiki/QR_Code