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Safer Than A Gamble: Finding Truly Random Numbers

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Safer Than A Gamble: Finding Truly Random Numbers

Science

Safer Than A Gamble: Finding Truly Random Numbers

Safer Than A Gamble: Finding Truly Random Numbers

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  • <iframe src="https://www.npr.org/player/embed/125993584/125997478" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
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Even the spin of a seemingly random roulette wheel can be predicted if you have the right information, says Antonio Acin of the Institute of Photonic Sciences in Barcelona. iStockphoto.com hide caption

toggle caption iStockphoto.com

Even the spin of a seemingly random roulette wheel can be predicted if you have the right information, says Antonio Acin of the Institute of Photonic Sciences in Barcelona.

iStockphoto.com

Using Random Numbers

Random numbers are commonly used for data encryption, selecting random samples for research, and of course, for lotteries and gambling. Mads Haahr, moderator and operator of random.org, a random number generator, wrote in an e-mail that Internet data encryption is one of the most common applications of random numbers.

"Effectively, online security is completely dependent on random numbers," Haahr wrote. "But you never see them."

Truly random numbers, Haahr wrote — not those generated by an algorithm — are crucial not only for encryption and data security, but also for lotteries and gambling.

Haahr also maintains a list of the unique uses of random numbers site users have sent him. They range from office mates choosing a restaurant to testing audio equipment.

Source: Mads Haahr, random.org

— Rose Raymond/NPR

Randomness is hard to come by. At least things that are absolutely, positively, 100 percent random.

Take the example of a roulette wheel: It may seem that the number the ball falls on is a random event, but Antonio Acin of the Institute of Photonic Sciences in Barcelona says it's not.

"If you are able to compute the initial position and the speed of the ball, and you have a perfect model for the roulette, then you can predict where the ball is going to finish — with certainty," Acin says.

In fact, he says everything that appears random in our world may just appear random because of lack of knowledge.

Is Anything Truly Random?

So to find true randomness, Acin and his colleagues turned to the world of atoms and electrons, and to the laws of quantum mechanics.

"To be more precise, we are taking advantage of the nonlocal correlations of entangled quantum particles," he says.

So that means that the laws of quantum mechanics say some things truly are random, like for example, the clicks a Geiger counter makes when it measures something radioactive.

"Those are random, due to quantum mechanics," says Christopher Monroe, Acin's colleague at the University of Maryland.

But Monroe says there's a problem with the random clicks of a Geiger counter. You can't be certain that the box the counter is in doesn't have a mechanical flaw, or even worse, a device that records the clicks and sends them to your enemy.

"A stronger form of random-number generators are so-called device independent. It doesn't matter what's inside the box," Monroe says.

Tied Up In Quantum Entanglement

This is where the weird properties of quantum mechanics come in. In this world, you can have a magnet that is pointing north and south at the same time, so long as you don't look at it.

"And when you do look, it randomly pops into one or the other," Monroe says.

So to capture that random popping, Monroe took an atom of ytterbium (a soft silvery metallic element), which has "an outer electron that is very much like a bar magnet," he says. "It can be north up or south up."

Then he took a second ytterbium atom and entangled them. He yoked them together in a quantum sense. The work of Albert Einstein and another physicist, John Bell, says if you can entangle two atoms, then you can prove when they pop out of their simultaneous up-and-down state, they will do so randomly.

"It turns out that quantum entanglement is very hard to come by," Monroe says.

Randomness, Cryptography And Casinos

It took three weeks of running their equipment to get just 42 random events — 42 ups or downs — that could be turned into zeroes or ones that were truly, totally, 100 percent random.

That's a crucial property for cryptographers who want uncrackable codes. It could also be important for casino operators. Antonio Acin says he could help an operator who wants to prove his games are completely based on chance — completely random, that is.

"I prepare for him two entangled particles. Now he takes these entangled particles to his lab. He knows he can generate randomness out of them," says Acin.

Of course, random or not, the house still gets a cut.

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