The Future of Personal Security

PROTECT YOUR SECRETS

Data thieves will soon have to crack the toughest lock imaginable: quantum weirdness

THE THREAT:
Losing private data to online eavesdroppers. When you send your banking information or other sensitive data over the Internet, it´s protected by cryptographic keys made from sequences of prime numbers. Right now it would take hackers days to crack these keys and break in. But the exponential rise in computing speed is shrinking that time, forcing researchers to devise new approaches to hack-proof communication.

THE SOLUTION:
Use the built-in randomness of quantum theory to lock and unlock data, eliminating the possibility of a break-in. In an experimental network designed by Cambridge, Massachusettsâ€based BBN Technologies, a laser creates a key out of individual bits of light, or photons. It sends this key along a fiber-optic cable, and another optical device at the end of the line collects the photons and records the key. If the received photon sequence matches up with the one conveyed by the sender, the recipient is permitted to use this key to gain access to top-secret data over the network.

If an intruder tries to use a photon detector or other tapping device to snoop on the transmission, however, the eavesdropping attempt will irreversibly damage the photon sequence. This is because of the central rule of quantum physics: Observing impossibly small entities, like electrons and photons, necessarily alters them. â€If someone´s trying to listen in, they change the quantum state of the photons as they´re going through the channel,†says Jonathan Habif, a physicist at BBN. â€You can´t measure a quantum state without changing it.†Any such change is obvious, and alerts network administrators to the possibility of a break-in.

The high cost of specialized photon detectors means that quantum-secured networks will initially be reserved for classified government chats and high-value bank transfers. Still, Habif has wide-ranging goals for the future. â€People will be able to use quantum cryptography for all kinds of transactions as the technology becomes cheaper and easier to implement,†he says. â€This could become the standard in communications security.â€

THE ETA:
When BBN first designed its prototype network, quantum cryptography could be used only to protect messages sent a couple miles or less. Last year, BBN researchers developed a more powerful single-photon detector that picks up even the faintest signals, increasing network range to more than 50 miles (new detectors in the works should extend it even further). Expect quantum-level security for consumers in about 10 years, after a test run of a few years in government settings. -Elizabeth Svoboda