Fighting Counterfeiters With Quantum Money

the_newsbeagle writes "This article discusses a proposal to create cash that can't be counterfeited by embedding quantum particles in banknotes. A counterfeiter trying to copy a real bill would have to precisely measure all the attributes of the embedded quantum particles — which is impossible under the tricky laws of quantum mechanics (PDF). MIT computer scientist Scott Aaronson, who famously offered a prize for anyone who could prove quantum computers are impossible, said, 'This is science fiction, but it’s science fiction that doesn’t violate any of the known laws of physics.'"

Comments

Sooo

[ae1294]

What happens when someone needs to look at the money to verify it's not counterfeit?

Re:Sooo

[girlintraining]

What happens when someone needs to look at the money to verify it's not counterfeit?

They get a cat that might be alive.

Re:Sooo

[Anonymous Coward]

I thought we settled it yesterday that you could just take the dead cat and turn it into a helicopter to raise money.

Re:Sooo

[hajus]

You can measure the bit in 1 of 3 dimensions. Let's say the bank measured it in dimension x out of x, y, and z. Now if you want to measure it, you can measure it in any of those dimensions. If you measure in x, you don't mess it up, but if you measure in y or z, you mess up the x reading and it gets randomized. Now if you have 64 bits, then you have to guess all 64 dimensions correctly, or you'll mess something up just by measuring it in a different dimension than what the issuing bank measured. Now all the bank has to do is record which dimensions the bill was measured in and what they got 0, or 1. If someone tried to measure it or made a fake one, then the bank will see all wrong numbers, either scrambled because of wrong measuring, or wrong because whoever issued the fake currency put in different random settings.

This sucks at the point-of-sale

[Anonymous Coward]

Where they have to use cats instead of the much simpler counterfeit checking pens.

This will be a profit loser and allergic shoppers will suffer in particular.

Re:This sucks at the point-of-sale

[Anonymous Coward]

Actually, they test for cocaine residue.

Schrodinger's Money

[Daetrin]

You never know if you still have any left until you open your wallet to check.

Re:Schrodinger's Money

[plover]

You never know if you still have any left until you open your wallet to check.

I've got matrimonial money. I don't have to open my wallet to know my wife has it all.

Re:Quick question

[Quantus347]

Sure because bitcoin is so very secure

Why bother with the technobabble?

[Powercntrl]

If you're tracking the serial numbers of a bill in a database, skip the quantum brainhurt and just do the same thing video game authors and cell phone companies do: make sure the serial number isn't being used in more than one place at a time. Duh.

Seriously, it's like trying to invent a phaser so you can light a campfire, when the rest of us would just use a match.

Huge upfront cost

[Quantus347]

This is one of those things that might well work in a limited situation (tracking marked bills to reveal criminal activity, etc) but the cost of Encoding, recording, and (securely) logging every bill as it is printed just isnt something that would be feasible for the majority of bill denominations. Maybe if it was limited to large quantity bills or something...

Make American dollars more sophisticated

[swb]

Besides a slight cut in seigniorage, why don't they make American dollars more difficult to counterfeit? Using materials, colors, etc that would only allow the most skilled counterfeiters (ie, North Korea or other groups with state backing) to copy them?

A lot of foreign currency has different sizes of bills, little plastic windows, metallic inks (or it could be mylar) and so on that would be extremely challenging.

I know they've tried to make American money more difficult to counterfeit (micro-printing, watermarking, etc) but it seems like people just keep bleaching out the ink and turning $1s into $20s or $100s because its so darn easy, which in turn makes it easier for the pros to turn out really good fakes, especially overseas.

It's almost enough to make a guy put on his tin hat and try to think up reasons why the government would WANT the currency counterfeited, especially overseas where it would have less impact on the native dollar economy but keep the currency supply large enough to maintain dollar-as-defacto-currency status...

Re:Make American dollars more sophisticated

[operagost]

This is a list of all the anti-counterfeiting measures in US currency. People still take fake bills because they just don't bother to check.

        Fiber Embedded Paper. The paper used to print our currency has tiny threads of fibers embedded into the paper. If the bill has no tiny fibers of red and blur embedded into the paper, it is probably a fake bill. Embedding fibers into the paper is one of anti-counterfeiting measures used to make it harder to make fake currency.
        Border Scroll. On the edges of a bill are fine lines in a scroll shape. The thin, fine lines are sharp and clear on an authentic bill. If you try to use a scanner and printer on your home computer to print your own money, the border art will appear blurry and the lines will run together.
        Security Thread. A security thread is embedded into the paper money and runs from the top to the bottom of the bill. It is printed with the currency amount. When held over an ultraviolet light the security thread will glow red. The security thread is one of the ten anti-counterfeiting measures that work the best to stop people from making fake money and devaluing our currency.
        Color Shifting Ink. On the $100 bill, a color shifting ink made with metallic flakes is used. On the $100 logo, the ink color will shift from black to green depending on the angle you are holding the bill.
        Microprinting. Microprinting involves printing in such a tiny font that it simply appears as solid lines but when viewed under magnification you can read the printing. Microprinting is an ant-counterfeiting measure that makes it extremely hard, if not impossible, for the average person to print fake money at home.
        Serial Numbers. Printing serial numbers on currency makes it harder for counterfeiters to forge fake money. In a large batch of fake currency, the counterfeiters may be forced to use the same serial number on all the bills making it easier to spot the fake bills. On fake bills, the serial numbers may not be evenly spaced or sized which is a dead give away that the bill is fake.
        Watermark. A watermark is embedded into the paper during the actual process of printing the paper. A watermark is very hard if not impossible for most counterfeiters to accurately replicate. A watermark is one of the ten anti-counterfeiting measures used to easily distinguish real currency from fake currency.
        Paper Color. The Yellow and Greenish colored hues used paper money makes bills hard to duplicate at home. A counterfeiter will have a hard time trying to duplicate the color scheme of an actual bill.

let's be honest here...

[Thud457]

Maybe I'll pay you Tuesday for a hamburger today.

Re:Gold

[betterunixthanunix]

I agree, it would be utterly horrible if money actually increased in value over time.

Spoken like someone who has never had to repay a loan...

Re:Quick question

[X0563511]

Lets be fair: it could be possible this is because it's so much easier to break in and steal them, then work out how to fake them. This doesn't mean it's impossible to do.

The six billion dollar $20 bill

[Narrowband]

When it costs eight or nine orders of magnitude more to produce the money than the face value of the money itself, that's generally regarded as a design flaw. It's a sure bet that you could absorb a whole heck of a lot of losses from counterfeiting for the cost of inventing new quantum particle manipulation and testing technologies and distributing them throughout a banking/finance system. By the time it pays for itself, you'd need to have currency that can survive commerce via warp drive.

Separate point -- even if the physics don't preclude the whole concept, what do you want to bet you couldn't do the testing in a non-destructive manner (i.e., without affecting the properties of the quantum particles). "Well, it WAS a real $20 bill. Oops."

Re:Quick question

[Khyber]

"You'll still get upvotes"

Back to Reddit with ye. This is Slashdot.