Tim Churches wrote: > [EMAIL PROTECTED] wrote: > > >[EMAIL PROTECTED] wrote: > > > > > >>This can be interesting: > >>http://science.slashdot.org/science/05/03/01/2340238.shtml > >> > >>Bearophile > >> > >> > > > >Hey, that DataGlyph demo works pretty neat. > > > > > ... > > >Of course, being an old System Test Engineer whose job it > >was to figure out how to break software, I couldn't let > >this challenge go unanswered. > > > >So, picking up the gauntlet, I broke it in 5 seconds. > > > > > ... > > >Naturally, the real answer is none of the above. > > > >And the damage can be undone in 5 seconds also. > > > >And, under the right circumstances, an undamaged > >DataGlyph could suffer the same fate (which also implies > >that the damaged DataGlyph could be read under the > >same circumstances). > > > >ObPuzzle: how did I "damage" the image? > > > > > You created a mirror image.
Damn. Too easy. But think how much fun you could have with a salesman if your DataGlyph was printed on a transparency (hence, the right circumstances being right side up or upside down). I once made an employee id badge that I would slip into the salesman's stack of test badges. The employee's name was CHECKSUM ERROR. What a laugh riot. > > The system can be made resistant to that problem by only allowing > palindromic messages to be encoded, such as "Madam I am Adam.", 'Able > was I ere I saw Elba." and "Named under a ban, a bared nude man." Why couldn't they simply encode your input as a palindrome? Input: Mary had an aeroplane Encoding: Mary has an aeroplaneenalporea na dah yraM And then simply divide in half when decoding. > > Seriously, I am surprised that the Xerox demo does not try flipping the > image around various axes. It would be trivial to add these > transformations. Well, trivial to flip images along a few, obvious axes, > but not along every possible axis. That's why it took me all of 5 seconds - the time needed to select the Flip Horizontal menu item in Windows Paint. > > What I want to know is whether any open source implementations of this > technology are available. No doubt it is patented to death by Xerox. Has that ever stopped anybody? > > Tim C -- http://mail.python.org/mailman/listinfo/python-list
