In 2013, Edward Snowden, a U.S. National Security Agency contractor, leaked documents showing that intelligence agencies were spying on the data of private citizens. One disturbing fact was that the spies tapped into optical fiber cables to access the huge amount of data moving through these cables.
Snowden’s disclosures pushed researchers to use quantum science to make this type of hacking impossible. Finally, there are reports of progress.
THE QUANTUM KEY DISTRIBUTION APPROACH
A startup called Quantum Xchange will access 500 miles of optical cable along the Eastern U.S. coast. Quantum will use this cable to create the country’s first quantum key distribution (QKD) network.
Quantum Xchange’s “QKD approach” would send an encoded message in bits while transmitting the decoding keys as quantum bits, or qubits. Usually in the form of photons, the qubits travel easily along fiber cables. However, any attempt to spy on a qubit would instantly destroy its fragile quantum state, erase any data and leave the mark of an intrusion.
One possible issue is that “trusted nodes” must be used to send quantum keys over long distances. These nodes act as repeaters to boost signals in a typical data cable. Quantum Xchange plans to have 13 trusted nodes along its entire network. At these node points, keys are first turned into bits. Then, they are changed back to a quantum state to be sent on. In other words, a hacker could theoretically steal these bits as they are momentarily vulnerable.
AN ALTERNATE METHOD: QUANTUM TELEPORTATION
Along with this news, the University of Chicago, the Fermi National Accelerator Laboratory and Argonne National Laboratory will jointly develop a test bed to use quantum teleportation to create secure data transmission.
Quantum teleportation would use entanglement to eliminate the risk of hacking. Entanglement creates a pair of qubits (usually photons) in a single quantum state. A change in one photon instantly affects the linked photon, even if they are far apart. Therefore, in theory, it should be impossible to hack data transmission using entanglement. This is so because tampering with one of the qubits would destroy both quantum states.
However, the entanglement method is still confined to research labs. And there are huge challenges to making this approach work in the real world. According to Dr. David Awschalom of the University of Chicago, creating and maintaining entanglement would be extremely difficult over a long-distance fiber optic network.
Dr. Awschalom is leading the project involving the university and the national labs. The goal is to have the test bed use a “plug-and-play” approach that will let the researchers experiment and evaluate different techniques for entangling and transmitting qubits.
The U.S. Department of Energy will provide several million dollars to fund the test bed. This test bed will use a 30-mile stretch of installed optical cable between the labs. Members of the Chicago Quantum Exchange will operate the test bed and project. This Exchange consists of 70 scientists and engineers from the three organizations.