Quantum encryption is so powerful because it's impossible to listen in on the data without corrupting it. Quantum bits can't be copied, so any attempt to listen in changes them and alerts the people communicating that something is up.
ID Quantique's technology is focused on quantum keys distribution. To ensure security, their technology, which is a kind of card that fits into a server, generates a string of random bits. To make them truly random, a laser diode fires a beam at a mirror that is 50 percent reflective. Any given photon has a 50 percent chance of being transmitted or reflected, to generate a 0 or a 1.
The random bit string is sent on the fiber-optic communications link. If the random bits don't look the same at the other end of the line, they've been hacked and the system sounds the alarm. If all is well, the machine sends the encryption key. Since the keys are also quantum-generated bits, any tampering - any attempt to steal the key - will be detected immediately.
The technology is designed for use in local area networks or between data centers and offices that are relatively close together, said Gregoire Ribordy, CEO of ID Quantique. That's because one of the limits of the technology is that you can't boost the signal the way you would over a conventional fiber optic line, because it would require copying the data which quantum mechanics says you can't do. That limits the distance to 60 miles or so.