(Bloomberg) A fiber-optic cable that harnesses the power of quantum mechanics to protect critical banking data from potential spies is running through the Holland Tunnel between Lower Manhattan & New Jersey. Quantum Xchange has been operating the cable in the Holland Tunnel since the fall. Quantum Xchange’s CEO Prisco says several large banks and asset management firms are testing his gear.
The cable’s carrying a technology called quantum key distribution, or QKD. It’s not difficult to physically tap normal fiber optics and intercept whatever messages the networks are carrying and the people communicating have no way of knowing someone is eavesdropping, because they’re still getting their messages without any perceptible delay. QKD solves this problem using quantum physics characteristics of light—normally thought of as a wave—can also behave like a particle. At each end of the fiber-optic line, QKD systems fire data in weak pulses of light, each just a little bigger than a single photon. If any of the pulses’ paths are interrupted and don’t arrive at the endpoint at the expected nanosecond, the sender and receiver know their communication has been compromised.