2014-11-01 22:48 GMT+01:00 Tom Mitchell :

On Fri, Oct 31, 2014 at 11:51 PM, grarpamp wrote:

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On Fri, Oct 31, 2014 at 2:57 PM, Dave Horsfall wrote:

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On Fri, 31 Oct 2014, Harald Hanche-Olsen wrote:

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Are you perhaps thinking of the so-called EURion constellation?

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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.