2014-11-01 22:48 GMT+01:00 Tom Mitchell <[1]mitch@niftyegg.com>:

   On Fri, Oct 31, 2014 at 11:51 PM, grarpamp <[2]grarpamp@gmail.com>
   wrote:

     On Fri, Oct 31, 2014 at 2:57 PM, Dave Horsfall
     <[3]dave@horsfall.org> wrote:
     > On Fri, 31 Oct 2014, Harald Hanche-Olsen wrote:
     >
     >> Are you perhaps thinking of the so-called EURion constellation?

   ...

     [4]http://www.secretservice.gov/know_your_money.shtml
     Quality counterfeiters of US notes don't care what

   One of the driving forces to the changes in currency around
   the globe was angst and some evidence of nation level
   counterfeiting.   Some small number of folk still have first
   hand knowledge of currency attacks in WW2 and how effective
   (or not) these attacks were.  Good accounts are sparse and
   like other secrets seem to still be closely held.
   I know that the local farmers market and flea market vendors in
   this area are very cautious about $20 bills that are apparently
   color printer and color copier produced.
   I did see some mumble about N. Korea and very high
   end intaglio printing about the same time the US and other
   nations started changing methods and designs.  A secretive
   well funded organization or government can do a lot to
   produce counterfeit money.   A decade or two earlier a lot of
   effort was spent on durability.

   I was about to mumble a tune about SuperDollars and ww2 currency
   devaluation attacks! They never really worked, or turned feasible,
   because delivery is quite hard and printing currency is quite
   expensive.

   It goes without saying that the secret service can use OCR
   readers in multiple locations and track each and every printed
   bill.   If their audits detect an interesting level I can see the next
   revision of design getting released into the cycle and aggressive
   audited shredder action for the previous.

   They hopefully do.
   But this is a crypto forum, right? So we can do better than just making
   hard-to-produce bills. We can produce an actual signature scheme!
   Using any crypto-currency but accepting double spends until an online
   check with central authority (blockchain is just a slow and
   decentralized central authority) can be done is probably really quite
   good. Optionally TPM's can put the central authority in your pocket, or
   in your bill!
   Too bad government sucks at technology.

References

   1. mailto:mitch@niftyegg.com
   2. mailto:grarpamp@gmail.com
   3. mailto:dave@horsfall.org
   4. http://www.secretservice.gov/know_your_money.shtml