sewilco@mecc.UUCP (Scot E. Wilcoxon) (02/10/86)
The spacing between characters can be used as a code.
I'm sure this has been done before with older technologies.
Laser printers with resolutions in fractions of an inch make
positional coding almost simple. Incidentally, such codes
could also be mechanically read with a page scanner.
The application which prompted my thoughts is the widespread
use of numbered copies of documents, and the occasional leaks
of them. If each copy of a document has a document number
coded by positional coding, a leaked photocopy might show
the coded number and help find the source of the leak.
--
Scot E. Wilcoxon Minn. Ed. Comp. Corp. quest!mecc!sewilco
45 03 N / 93 15 W (612)481-3507 {ihnp4,mgnetp}!dicomed!mecc!sewilconcx@cheviot.UUCP (02/13/86)
This is precisely the method used (we are told) by UK government departments so that the sources of leaked documents can be traced.