With security on the Internet, there's always some nagging doubt. Can you ever be absolutely certain, for example, that the e-mail you're sending with some confidential business information attached isn't going to be intercepted and read as it travels the digital highways and byways? Using the Internet for anything sensitive requires some faith that everything in place to ensure the security of the information you're working with
But uncertainty can be useful. For years, security researchers have been experimenting with harnessing one of the underlying rules of quantum physics, known as the Uncertainty Principle, which states that at the quantum level, where objects are infinitely small, it's impossible to measure electrons and photons and other similarly tiny particles without affecting them. How does quantum physics apply to the world of security? The idea is to harness this inherent uncertainty to create a data-encryption scheme that's essentially unbreakable. It's called quantum cryptography, and already some governments and private companies are using it to build absolutely secure lines for data and voice communications.

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