Unbreakable Encryption Scheme?

Craig Tyler
lanl.gov

Quantum cryptography for the consumer

Valuable information, personal information, secret information—each is transmitted all around you, all the time. To prevent that information from reaching thieves, spies, and terrorists, it is encrypted, with the intent of rendering it indecipherable to everyone except its intended recipient. And encryption, or more generally, cryptography—the science of encoding information—stands on the verge of a technological revolution.

Encryption usually involves one or more secret keys—numbers used in some mathematical operation to protect the sensitive information. For example, suppose the message to be sent is the number 4, the key is the number 3, and the encryption scheme is simple multiplication. Then the encrypted message is 12 (because 4 x 3 = 12). The receiver would divide the transmitted number, 12, by the key, 3, to recover the original number, 4. In a more realistic application, the key could be hundreds of digits long and use an algorithm much more sophisticated than simple multiplication. Either way, without the key, you can’t unlock the information.

But what if you could calculate the key? Perhaps you could use an algorithm to test lots of different numbers until you hone in on the right one. This is indeed possible. The security of conventional encryption relies on the mathematical difficulty, not the impossibility, of calculating the key. An encryption scheme might be considered secure if the fastest computers in existence today would take decades, say, to break it. The point is, it can be broken. It’s just a matter of time until the available computing power becomes sufficient. “You’re betting against technology,” says Los Alamos physicist and quantum communications team member Raymond Newell. “That’s not a safe bet.”

Fortunately, practical quantum cryptography, which includes encryption schemes that neither today’s computers nor future computers can defeat, has arrived. Building on 17 years of basic and applied research and a long string of experimental breakthroughs, Los Alamos scientists Jane Nordholt, Richard Hughes, Raymond Newell, and Glen Peterson have designed and built a handheld quantum cryptography system for the consumer. The system creates and shares, on demand, an encryption key between a sender and receiver. It then uses a transmission protocol based on quantum physics to ensure that the key can never be harmfully intercepted. And unlike a classical key, a quantum key cannot be revealed through calculation. This technology is currently being offered for license to the private sector to be used for everyone’s benefit, making encrypted transmissions secure into the future.

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