Researchers in Europe in the field of quantum cryptography have demonstrated for the first time that it should be possible? with the help of satellites? to communicate across thousands of kilometers using unbreakable codes whose security is guaranteed by the laws of quantum physics. For many business or government uses, the codes must be usable between cities and continents, but quantum cryptography machines today are limited to about 150 kilometers by the length of individual optical fibers and the loss of photons within them.