Quantum Crypto Gets a Chance

The price has dropped, and the science is more practical, but that doesn't mean it's for everyone

November 13, 2003

4 Min Read
Quantum Crypto Gets a Chance

Quantum cryptography is starting to emerge in commercial form, but it's far from being a major part of the industry. In fact, even if it works as promised, the technology applies only to specialized situations and needs.

Products are finally coming to market, though, the culmination of more than a decade of research. Both ID Quantique in Geneva and MagiQ Technologies Inc. recently launched products in this market for the esoteric stuff.

Quantum cryptography doesn't replace all of cryptography. It handles only one aspect, known as the key exchange. The key is the number that allows anyone to crack the code, so obviously, cryptography doesn't work unless the key is kept secret.

"Quantum cryptography" refers to a way of sending that key. It's done with individual photons and exploits the principles of quantum mechanics. Anyone tapping the line to observe the photons will disrupt the process, and both the sender and receiver will know they've got an intruder. Once the key is received, the rest of the security process is handled normally: Data is encrypted using conventional electronics and sent along the usual copper or fiber route.

The key to quantum key exchange lies in having a detector sensitive enough to work at the individual photon level. That's the product ID Quantique has concentrated on, along with a hardware-based random-number generator (see Quantum Cipher Sent by Fiber).

MagiQ's trick was to take advantage of commercially available parts and bundle them into a box, the first time that's been attempted for the commercial market. MagiQ is developing its own photonics as well, but for now, the photonic detector inside its box comes from another company, as do the electronics that perform the encryption and data handling (see MagiQ Demos Quantum Cryptography and Startup Says Quantum Crypto Is Real).

This wasn't practical before now, due to the price. "One of the optical components we use costs $500. Three or four years ago, it would have cost $15,000," says Bob Gelfond, MagiQ CEO.

Price hasn't been the only barrier, though. Tom Hausken, an optical components analyst for Strategies Unlimited, actually had a look at quantum crypto about 10 years ago as a staff member at Congress. He helped conduct an analysis that ultimately deemed the technology impractical. At the time, it couldn't cover long distances and required polarization-maintaining fiber.

Distance is a problem because the farther the photon travels, the greater the chance of it getting absorbed or scattered. In other words, it might not reach the other side. But researchers have gotten photons to survive longer and longer trips. Mitsubishi Electric Corp. reported transmissions of 87 kilometers a year ago, and NEC Corp. (Nasdaq: NIPNY; Tokyo: 6701) boasted of a 100km, single-photon transmission in July (see Mitsubishi Creates Quantum Crypto and NEC Transmits Quanta).

And most efforts these days don't need specialized fiber. "We're really focused on using standard telecom fiber. The better the fiber, the better the distance, but -- standard fiber," says Grégoire Ribordy, CEO of ID Quantique.

But there's another troublesome factor: The quantum key exchange has to take place on a dedicated fiber; you can't have other traffic piling its way in there and mucking up the single-photon transmission. For that reason, the technology is still aimed at "a very restricted class of networks," Ribordy says, conceding that "it's not going to replace the existing technology" any time soon.

But here, MagiQ claims to have still more tricks up its sleeve, including a way to send the quantum key distribution across ordinary DWDM links. That technology won't emerge any time soon, however, and Gelfond isn't giving any hints about the timeline.

Despite all the progress, there's a chance quantum cryptography might never have its day. For one thing, it's debatable whether companies need the "unbreakable" security of quantum crypto. "The greatest threats to computer security are: fire and water damage, system failures, insiders, worms, and viruses. Taps are way down the list, so far as we know," Hausken writes in an email.

It's certain that quantum cryptography will continue to advance, due especially to government interest. Both ID Quantique and MagiQ also report seeing interest from the financial community. But Hausken and others doubt whether the concept matters much to the greater commercial world.

He's also a bit leery about whether the technology is really ready for commercialization. After hearing about MagiQ's box last week, he noted that security is an area that's important but still tends to be overhyped.

"Sometimes there are companies that exploit the public's ignorance of a subject for personal gain. It's no different than food supplements or skincare products, I guess. So I'm not saying that anyone is a shyster. Let's call it opportunism," Hausken writes.

— Craig Matsumoto, Senior Editor, Light Reading

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