Re: Creating a unique ID number for a dollar

[Tim May <tcmay@got.net>]

At 12:44 PM -0700 6/2/97, Peter Gutmann wrote:
>Death rays from Mars made Tim May <tcmay@got.net> write:
>
>>There's a way to generate a number for any person which is unique. It is not
>>shared by anyone else on the planet.
>
>It's not guaranteed unique.  First, the dollar you use may be a forgery (why
>forge a dollar?  I don't know, maybe they're practicing on low-denomination

Sure, these are all possible protocol failures. (Likewise, one could use
the number but not destroy the bill and instead pass it on, thus producing
collisions.)

Assuming the bill is not a forgery...not terribly hard to confirm,
especially if given the time likely to plan for execution of the
protocol--and assuming one follows the protocol....

(Note: costs of forgery are real. Fibers in the paper, the paper itself,
etc. I doubt it would be economical for a forger to enter the dollar bill
market. Maybe specifically to spoof the protocol, but that is guarded
against in the expected ways, e.g., by picking from a large pool of bills
at, say, a flea market or other business, by choosing a well-worn bill,
etc. Neither information-theoretically nor cryptographically secure, to be
sure, but "agorically secure," to coin a phrase.)

>somewhere).  Does the US Treasury issue replacement notes if the originals
>are
>damaged in printing, or does it just destroy the notes and leave it at that?

Don't know.

But certainly a dollar bill burned up as part of this protocol is unknown
to them, and would of course never be reprinted (print runs are obviously
done in large batches, with auto-indexing of numbers across sheets, so
"one-offs" would never be done anyway).

--Tim May



>
>Peter.


There's something wrong when I'm a felon under an increasing number of laws.
Only one response to the key grabbers is warranted: "Death to Tyrants!"
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Timothy C. May              | Crypto Anarchy: encryption, digital money,
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