Unbreakable messages: quantum key distribution

First proposed in 1984 -- the year not the novel -- quantum key distribution (QKD) has gotten a second look from researchers at the Institute of Physics and German Physical Society. QKD systems have been used commercially since 2007, when Switzerland used one to encode the national election ballot results. Most modern-commercial QKD systems utilize lasers that emit photons at random intervals, and as a result are not secure. “The random nature of emission events sometimes results in...