Some people say that the most valuable thing in the modern world is information, and if that is true than the ability to secure that information is also going to be very valuable. Numerous systems have been developed to protect digital information from being stolen and quantum encryption is one of the strongest systems available now, but does have some weaknesses, such as limited range. Researchers at MIT have developed a new quantum encryption method though that can address the range issue as well as limits on transmission size.
Quantum encryption takes advantage of certain properties and phenomena of quantum mechanics to make eavesdropping on a transmission impossible, without being exposed, because measuring a quantum signal changes it. The quantum mechanical properties and phenomena used though are quite fragile, which limits transmission range, but the researchers have found a way around that. Even though during transmission noise will disrupt a signal, the researchers determined that if a megabit of data were sent between two people communicating legitimately, only one bit would get flipped due to the noise. If there were an illegitimate listener though, an eavesdropper, half of the bits they receive would be flipped, making the signal useless to them.
This is certainly an important discovery for enabling fully quantum-encrypted communication, but does have one weakness, at the moment. In its current form, this method is only strong against passive eavesdroppers, who just listen in, but an active eavesdropper who affects the transmissions would be able to defeat it, at least until more research is done to strengthen this system against them.