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Total Satellite Secrecy Approaches August 31, 2001 7:05 CDT Researchers at Los Alamos National Laboratory in California have now built a portable system that will allow electronic messages to be transmitted to and from satellites. All of the transmissions will be done in absolute secrecy. According to New Scientist, the researchers will test the system to send quantum information 10 kilometers through horizontal free space at the start of September. Air density at this at this level approaches that experienced when transmitting information to a satellite 300 kilometers above the Earth. "This is a significant step towards that threshold," Tim Spiller, of the Quantum Information Processing Group at Hewlett-Packard Laboratories in the UK told New Scientist. "This group is leading the world in this area." The furthest that anyone has yet managed to send this type of signal through free space is just two kilometers. Glen Peterson, who constructed the device at Los Alamos National Laboratory, is confident that the technology will work over 10 kilometers. He told New Scientist that new photon projection and detection hardware promise to improve the system's accuracy dramatically. "The next step is to track a satellite and make sure we get the signals right," he added. "We have people developing the hardware to go into satellites." The new system is made up of two devices that transmit and receive data encoded as individual photons with a quantum state. According to the laws of quantum physics any interference with the data stream would disrupt the stream, leading to detection. While other research institutes have demonstrated quantum cryptography in the laboratory, the technique has not yet been used to secure sensitive messages. Normally, quantum cryptography may only be used to update the "keys" used to lock and unlock encrypted messages sent through normal satellite links. While this would greatly improve the security of satellite communications, it would not guarantee total secrecy. In addition, the system could be used to generate "one time" keys. These keys would provide absolute secrecy for individual satellite communications. These keys would require significantly more bandwidth. According to New Scientist, experts claim that the technique will probably not be used to perform the majority of communications, such as relaying internet messages, simply because significant extra cost and effort is required. "It's going to be used mainly in niche markets such as point-to-point government communications, where you need very high security," says Nigel Smart, a cryptography expert at the University of Bristol in the UK. Source: New Scientist |
