The polymer notes[1] we use in Australia (and also print for several other countries) have been around for about 18 years now and have very low rates of counterfeiting due to the number of security features built in[2].

The notes do cost more to produce, but the extra durability means that they last about 4 times as long (from memory) in circulation, so overall the cost difference is marginal for the government, but is an additional deterrent for counterfeiters.

[1] http://en.wikipedia.org/wiki/Polymer_banknote [2] http://www.rba.gov.au/banknotes/counterfeit/index.html

I just read an interesting article about Canada borrowing the polymer from the Australia. I didn't realize that until very recently, Canada had a really serious counterfeiting problem.

http://www.theglobeandmail.com/report-on-business/economy/cu...

I just received a polymer $100CAD bill the other day, I thought it was pretty bad ass. I had no clue that it was produced in Australia, and that this technology has been in circulation for a couple decades.

I do notice that when I had the when the bill was in my wallet that has a money clip (I hate big wallets), and when sat on, it produced a visible crease that's not as prevalent in the fiber notes along side it. Overall, I do see it as being more durable.

I fell for a fake Polymer banknote while on holidays in Brazil (the same Ten Reais banknote seen on Wikipedia).

As the top post said, it only needs to fool a human, not be perfect.

> have very low rates of counterfeiting due to the number of security features built in

Is it the security measures, or does the (relatively) small number of places where one can pass Australian currency result in fewer attempts?

US currency is somewhat familiar in a large number of countries, so there are lots of opportunities to get someone to take counterfeits.

Let's also remember that it's not incredibly hard to trick a human. (One of my favorite videos related to counterfeit currency is Derren Brown paying for things with blank paper http://www.youtube.com/watch?v=3Vz_YTNLn6w (And if you think he faked it, he's still managed to trick a lot of other people otherwise.))

I wonder how much in total method after method of trying to stay ahead of the Big Money counterfeiters has cost? Mathematical solutions to the problem of forgery have existed for quite a while, I wish there was more a push for those. (And I'm not necessarily talking about bitcoin either, it's just one of many possibilities.) Of course even just going digital for everything would probably solve a lot of problems, and there are math solutions to keeping different types of anonymity as well.

I read the article and they said they could even put watermarks that human can't see, only machines. Shops are already employing UV lights to check currency so I would imagine they would get something that could check for the invisible watermark.