[Cryptography] Checkoin: physical crypto-cash

[Ray Dillinger]

If the anti-duplicating measures work, why are we assuming that they are
better than those already applied to cash?

Cash already has the anti-counterfeiting measures built into banknotes,
already including holograms and fine-detail-random images in some
countries, probably to include RFIDs and cryptographic
challenge/response if and when it becomes cost-effective.

Cash already has the way banks detect duplication by tracking serial
numbers on higher-denomination currency.

Cash has the "tattletail" code in printers that puts identifying marks
on pages so documents including counterfeits can be linked to the
printer that made them.

Cash has the code in scanners and printers that detects attempts to
print currency and smudges the copy (and may send encrypted packets to
interesting places if connected).

Cash has existing police forces all over the world who recognize it, who
understand what counterfeiting is and why it is bad.

Cash has entire populations of people who already know exactly how it
looks and feels and what weight and texture it has.  The kid at the
fast-food place can routinely make a test with her eyes and fingertips
in a fraction of a second that a counterfeiter needs many weeks of work
to reliably overcome.  You will never get a more reliable test that fast
and easy.

You're looking for physical tokens of value to circulate with
anti-duplication measures? The ratio of general effectiveness to very
low cost is set by cash.  It's really very effective and very cheap to
produce and use, and will likely continue to take up new technology as
it becomes cost-effective.  It will be hard to convince anyone you have
a better solution.  It will be hard to build a better solution.

					Bear


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