Well, in the specific case of US currency, there's a bit of a general problem because all dollar bills printed at all times are deemed valid currency - at least in theory - including those with previous makes and security technologies. Old issues might be refused because they look strange, good counterfeits might be accepted because they don't.

On 12 July 2016 at 22:52, David Shaw <xxxxxx@gmail.com> wrote:

OK, but how many of them are good enough to fool a US citizen? They might fool me because, as a UK citizen who has never visited the USA, I have never seen a real $100 bill except in quick flashes on the TV but would they be accepted in a US store?

David Shaw

This email was sent from yahoo.com which does not allow forwarding of emails via email lists. Therefore the sender's email address (xxxxxx@yahoo.com) has been replaced with a dummy one. The original message follows:

----------------------------------------------------------------------------------------------------------------------------------------------

NorthKorea & Iran & (?) have been counterfeiting $100US for, literally, decades. In fact, years ago, my father showed me a newspaper article that stated that it was well known that anywhere from 1/3 - 1/2 of the US 100 dollar bills in circulation in parts of asia were counterfeit.

Life goes on....

--------------------------------------------------------------------------------------------------------------------------------------------------
On Tue, 7/12/16, Abu Dhabi <xxxxxx@gmail.com> wrote:

 Subject: Re: [TML] Currency
 To: xxxxxx@simplelists.com
 Date: Tuesday, July 12, 2016, 11:26 AM

 >Well, largely the way we’re not
 faced with instant, massive counterfeiting, fraud and
 hyperinflation today. The bills are made with
 anti-counterfeiting measures in place. microscopic encrypted
 keys readable by a bill checker, akin to modern counterfeit
 detectors, etc.
 OK. I
 can buy a anti-counterfeiting technology handwave, even if
 it's a little hard to believe in a setting incredibly
 more diverse than the European Union is (where a monetary
 union combined with federalism and diversity of economies
 have led to substantial financial difficulties, albeit
 different than I presented). 
 It is a little hard to believe
 partly because of the inevitable, hard-to-track-down
 criminals who would presumably have the capacity to kidnap
 an engineer or three and start taking verifiers apart, in
 order to reverse-engineer what an undetectable forgery is
 supposed to look like. Replacing compromised countermeasures
 sounds like a nightmare, because presumably all  legit
 Crimps everywhere need to verify as legit - unless you have
 multiple valid standards... in which case security is
 poorer, but you could limit damage; but it would still be
 horrifically painful to reimplement verification measures.
 I'm not sure issuing a new currency would go a smoothly
 as our RL currency changes do, simply because of the vast
 amounts of time needed to get information
 across.
 >Heck, during WWII the Germans
 printed, essentially, real 5, 10, 20 and 50  pound notes,
 and it didn’t work <https://en.wikipedia.org/wiki/Operation_Bernhard>.
 Reading that page makes me think
 it didn't work because it didn't have sufficient
 time to work - and not enough cooperation between right hand
 and left hand - before it was shut
 down.


 On 12 July 2016 at 18:30,
 Bruce  Johnson <xxxxxx@pharmacy.arizona.edu>
 wrote:

















 On Jul 12, 2016, at 7:27 AM, Abu Dhabi <xxxxxx@gmail.com>
 wrote:




 How

  does the Imperial Credit function? AFAIK, it is a paper
 (well - plastic) currency backed my the Imperial economy.
 How does this not lead to instant, massive counterfeiting,
 fraud and hyperinflation? The notes are supposedly proof
 against forgery, but I struggle

  to imagine how they could be.











 Well, largely the way we’re not faced with instant,
 massive counterfeiting, fraud and hyperinflation today. The
 bills are made with anti-counterfeiting measures in place.
 microscopic encrypted keys readable by a bill checker, akin
 to modern counterfeit

  detectors, etc.






 I’m sure it occurs, as it does here in the Real
 World, but it’s not a sufficiently large issue to cause
 problems. Heck, during WWII the Germans printed,
 essentially, real 5, 10, 20 and 50  pound notes, and it
 didn’t work <https://en.wikipedia.org/wiki/Operation_Bernhard>.






 Mechanisms exist today to manage anonymous but
 verifiable and uncounterfeitable currency: Bitcoin. It has
 it’s problems (primarily rooted in it’s inherent
 goldbuggery, but that leads to deflation, not inflation.)
 but the avenues for anonymous secure, and

  verifiable electronic transactions are there, and have been
 for quite some time: http://firstmonday.org/ojs/index.php/fm/article/view/474/830. http://groups.csail.mit.edu/mac/classes/6.805/articles/money/nsamint/nsamint.htm






 We had a long long
 <strike>flamewar</strike> cordial, but spirited
 discussion of electronic cash transfers on the list sometime
 in the last couple of years. 






 -- 


 Bruce Johnson


 University of Arizona


 College of Pharmacy


 Information Technology Group





 Institutions do not have opinions, merely customs









 -----
 The Traveller Mailing List
 Archives at http://archives.simplelists.com/tml
 Report problems to xxxxxx@simplelists.com
 To unsubscribe from this list please goto
 http://archives.simplelists.com


 -----
 The Traveller Mailing List
 Archives at http://archives.simplelists.com/tml
 Report problems to xxxxxx@simplelists.com
 To unsubscribe from this list please goto
 http://archives.simplelists.com
-----
The Traveller Mailing List
Archives at http://archives.simplelists.com/tml
Report problems to xxxxxx@simplelists.com
To unsubscribe from this list please goto
http://archives.simplelists.com
-----
The Traveller Mailing List
Archives at http://archives.simplelists.com/tml
Report problems to xxxxxx@simplelists.com
To unsubscribe from this list please goto 
http://www.simplelists.com/confirm.php?u=gKqKfFfLGCu4ffCaQQsgV6nFZ3rmoPaH