In message <[EMAIL PROTECTED] nk.net>, John Kelsey writes: > >On the other hand, think about the uses of this technology >for paper bearer instruments. Design travelers' checks that >include a 2D barcode with a BLS signature, bound to the >piece of paper, and you can print the damned thing on >regular paper if the readers are cheap enough. Similar >things apply to stamps, tickets, etc.
Tickets are an excellent use for this, because it binds the printing to a specific physical object. The concert industry has had a problem with trying to use print-at-home tickets -- the fraudsters buy a single ticket, then print it multiple times and sell the resulting tickets to others. One group is resorting to requiring ID at the door -- buyers will never have a physical ticket until after they're escorted inside, to eliminate the opportunity for such fraud. (See http://www.nytimes.com/2005/08/06/arts/music/06scal.html for more details.) Yes, you could do everything via an online system based on identity documents. Apart from the privacy implications, and the problem of coping with network failures just prior to the start of a concert or game, dealing with the multiple forms of ID people carry isn't easy; it requires a fair amount of preparation and infrastructure. As I said, people may be moving in that direction, but the article itself called the scheme "laborious"; the band's manager called it "unbelievably cumbersome". I don't disagree with Perry's basic statement -- that a lot of people try to solve the wrong problem. Here, though, we have a tool. It remainds to be determined if it's a hammer, screwdriver, or wrench, and hence what problems to apply it to. --Steven M. Bellovin, http://www.cs.columbia.edu/~smb --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to [EMAIL PROTECTED]