Abstract
The field of quantum information technology is becoming more exciting by the day, with new research continually pushing forward the boundaries of what is possible with quantum techniques. In practical terms the most advanced area of research is quantum cryptography, where quantum "keys" are used to safeguard information more effectively than is possible with existing cryptographic codes. In the latest advance, researchers at the Los Alamos National Laboratory have transmitted a quantum key a kilometre through the atmosphere, and suggest that the technique could be extended to achieve secure communications between the Earth and low-orbiting satellites (W T Buttler et al. 1998 Phs. Rev. Lett. 81 3283).