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Physicists go totally random

Calculations suggest way to boost the independence of information flow

Casino bosses, take note: Physicists have described a way to guarantee complete randomness in a flow of information, such as the numbers generated by a roulette wheel.

The work could allow a person to transform a stream of not-quite-random information into a totally random one. “Even if you don’t have perfect randomness, you can make perfect randomness,” says Roger Colbeck, a theoretical physicist at ETH Zurich in Switzerland. “This is sort of a guarantee given to you by the laws of physics.”

Colbeck and ETH Zurich colleague Renato Renner describe the finding online May 6 in Nature Physics.

True randomness — in which a coin flip has a 50 percent chance of coming up heads — is hugely important in fields such as cryptography. Patterns could be detected in a code based on less than random numbers, allowing it to be broken. And if a casino’s random number generators aren’t absolutely random, a gambler might be able to exploit that weakness.  

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