AN AEROPLANE has beamed quantum encryption keys to a station
on the ground, paving the way for an ultra-secure global communications
network.
Quantum key distribution (QKD) uses photons polarised in two
different ways to encode the 0s and 1s of an encryption key. The laws of
quantum mechanics ensure the transmission is secure, as any attempt to
intercept the key disturbs the polarisation - a tip-off to the receiver that
the key has been seen and should be discarded.
Quantum keys had previously been exchanged between two
land-based stations. Now Sebastian Nauerth at the Ludwig Maximilian University
of Munich, Germany, and colleagues have extended the feat to an aircraft, a
stepping stone to QKD via satellite, which could allow secure messages to be
transmitted around the world.