A Quantum Leap in Cryptography

In a dark, quiet room inside the Boston labs of BBN Corp. (VZ ), network engineer Chip Elliott is using the laws of physics to build what he hopes will be an unbreakable encryption machine. The system, which sits atop a pink heat-absorption table, is designed to harness subatomic particles to create a hacker-proof way to communicate over fiber-optic networks.

To build his black box, Elliott has used off-the-shelf fiber-optic gear such as lasers and detectors, which he has tweaked to do unusual things. The goal is to reliably emit and detect single photons or tightly linked pairs of photons -- the key particles in light waves. It's all part of a leading edge information-security field known as quantum cryptography.

Over the next few years, Elliott and others in the field may turn the information-security business on its ear. Quantum cryptography could make the secret codes that protect data transmissions far more difficult to decipher -- an important feature for financial-services companies, telecom carriers, and governments. Quantum cryptography may also quickly alert systems administrators to the presence of cybersnoops, whether they be hackers, fraudsters, or corporate spies.

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