If you want to send a perfectly secure message you may want to generate a completely random cipher to encrypt your data. But generating truly random numbers using computer algorithms is difficult and hidden patterns in sequences of supposedly random numbers can be used to by a determined eavesdropper to decipher the message.
So in recent years, physicists have turned to the quantum world. For example, send a single photon through a beam splitter with two paths and there is no way to know which path the photon will end up taking. At least one company makes a commercial random number generator based on this idea.
But the problem, says Paul Kwiat
, a quantum physicist at the University of Illinois in Urbana, US, is that each photon produces only one random bit. So the rate at which you can generate random numbers is severely limited.
He and his colleagues say a better, and simpler, way is to generate photons randomly and record the time each takes to arrive at a detector. This amount of time can be converted into digits to create a random number. In this way, a single photon can generate as many random digits as there are significant figures in the time measurement.
Read the full quantum random number patent application
.Justin Mullins, New Scientist contributor
Labels: mathematics, physics, quantum