Where's the smart money?

[Steven M. Bellovin]

In message <F504A8CEE925D411AF4A00508B8BE90A01E90C2C at exna07.securitydynamics.co
m>, "Trei, Peter" writes:
>That's the scenario which is (semi) worrying. As
>the tagged bills wear, some fraction of the RFID
>transponders will inevitably fail. When this happens,
>is the bill declared invalid? Will merchants regularly
>check all incoming cash for a good tag? Is a bill 
>with a bad tag presumed to be counterfeit? Can
>it be exchanged?
>

I can't speak for other countries, but the U.S. already has 
well-defined procedures for trading in damaged currency.  For example, 
if you have >3/5 of the bill, you get full value; between 2/5 and 3/5, 
you get half-value; below that, you get nothing.  I believe that such 
exchanges can be done at any bank, though I could be wrong about that.

Anyway -- I'd assume that similar procedures would be put in place for 
tagged bills.  Validation might inlude a waiting period to see if the 
tag corresponding to that serial number shows up.

		--Steve Bellovin, http://www.research.att.com/~smb
		Full text of "Firewalls" book now at http://www.wilyhacker.com



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